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Chapter 3. Secondary networks

3.1. Creating secondary networks on OVN-Kubernetes

As a cluster administrator, you can configure a secondary network for your cluster using the NetworkAttachmentDefinition (NAD) resource.

Note

Support for user-defined networks as a secondary network will be added in a future version of OpenShift Container Platform.

3.1.1. Configuration for an OVN-Kubernetes secondary network

The Red Hat OpenShift Networking OVN-Kubernetes network plugin allows the configuration of secondary network interfaces for pods. To configure secondary network interfaces, you must define the configurations in the NetworkAttachmentDefinition custom resource definition (CRD).

Note

Pod and multi-network policy creation might remain in a pending state until the OVN-Kubernetes control plane agent in the nodes processes the associated network-attachment-definition CRD.

You can configure an OVN-Kubernetes secondary network in layer 2, layer 3, or localnet topologies. For more information about features supported on these topologies, see "UserDefinedNetwork and NetworkAttachmentDefinition support matrix".

The following sections provide example configurations for each of the topologies that OVN-Kubernetes currently allows for secondary networks.

Note

Networks names must be unique. For example, creating multiple NetworkAttachmentDefinition CRDs with different configurations that reference the same network is unsupported.

3.1.1.1. Supported platforms for OVN-Kubernetes secondary network

You can use an OVN-Kubernetes secondary network with the following supported platforms:

  • Bare metal
  • IBM Power®
  • IBM Z®
  • IBM® LinuxONE
  • VMware vSphere
  • Red Hat OpenStack Platform (RHOSP)

3.1.1.2. OVN-Kubernetes network plugin JSON configuration table

The following table describes the configuration parameters for the OVN-Kubernetes CNI network plugin:

Table 3.1. OVN-Kubernetes network plugin JSON configuration table
FieldTypeDescription

cniVersion

string

The CNI specification version. The required value is 0.3.1.

name

string

The name of the network. These networks are not namespaced. For example, a network named l2-network can be referenced by NetworkAttachmentDefinition custom resources (CRs) that exist in different namespaces. This configuration allows pods that use the NetworkAttachmentDefinition CR in different namespaces to communicate over the same secondary network. However, the NetworkAttachmentDefinition CRs must share the same network-specific parameters, such as topology, subnets, mtu, excludeSubnets, and vlanID. The vlanID parameter applies only when the topology field is set to localnet.

type

string

The name of the CNI plugin to configure. This value must be set to ovn-k8s-cni-overlay.

topology

string

The topological configuration for the network. Must be one of layer2 or localnet.

subnets

string

The subnet to use for the network across the cluster.

For "topology":"layer2" deployments, IPv6 (2001:DBB::/64) and dual-stack (192.168.100.0/24,2001:DBB::/64) subnets are supported.

When omitted, the logical switch implementing the network only provides layer 2 communication, and users must configure IP addresses for the pods. Port security only prevents MAC spoofing.

mtu

string

The maximum transmission unit (MTU). If you do not set a value, the Cluster Network Operator (CNO) sets a default MTU value by calculating the difference among the underlay MTU of the primary network interface, the overlay MTU of the pod network, such as the Geneve (Generic Network Virtualization Encapsulation), and byte capacity of any enabled features, such as IPsec.

netAttachDefName

string

The metadata namespace and name of the network attachment definition CRD where this configuration is included. For example, if this configuration is defined in a NetworkAttachmentDefinition CRD in namespace ns1 named l2-network, this should be set to ns1/l2-network.

excludeSubnets

string

A comma-separated list of CIDRs and IP addresses. IP addresses are removed from the assignable IP address pool and are never passed to the pods.

vlanID

integer

If topology is set to localnet, the specified VLAN tag is assigned to traffic from this secondary network. The default is to not assign a VLAN tag.

3.1.1.3. Compatibility with multi-network policy

The multi-network policy API, which is provided by the MultiNetworkPolicy custom resource definition (CRD) in the k8s.cni.cncf.io API group, is compatible with an OVN-Kubernetes secondary network. When defining a network policy, the network policy rules that can be used depend on whether the OVN-Kubernetes secondary network defines the subnets field. Refer to the following table for details:

Table 3.2. Supported multi-network policy selectors based on subnets CNI configuration
subnets field specifiedAllowed multi-network policy selectors

Yes

  • podSelector and namespaceSelector
  • ipBlock

No

  • ipBlock

You can use the k8s.v1.cni.cncf.io/policy-for annotation on a MultiNetworkPolicy object to point to a NetworkAttachmentDefinition (NAD) custom resource (CR). The NAD CR defines the network to which the policy applies. The following example multi-network policy is valid only if the subnets field is defined in the secondary network CNI configuration for the secondary network named blue2:

Example multi-network policy that uses a pod selector

apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: allow-same-namespace
  annotations:
    k8s.v1.cni.cncf.io/policy-for: blue2
1 

spec:
  podSelector:
  ingress:
  - from:
    - podSelector: {}
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The following example uses the ipBlock network policy selector, which is always valid for an OVN-Kubernetes secondary network:

Example multi-network policy that uses an IP block selector

apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name:  ingress-ipblock
  annotations:
    k8s.v1.cni.cncf.io/policy-for: default/flatl2net
spec:
  podSelector:
    matchLabels:
      name: access-control
  policyTypes:
  - Ingress
  ingress:
  - from:
    - ipBlock:
        cidr: 10.200.0.0/30
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3.1.1.4. Configuration for a localnet switched topology

The switched localnet topology interconnects the workloads created as Network Attachment Definitions (NADs) through a cluster-wide logical switch to a physical network.

You must map a secondary network to the OVN bridge to use it as an OVN-Kubernetes secondary network. Bridge mappings allow network traffic to reach the physical network. A bridge mapping associates a physical network name, also known as an interface label, to a bridge created with Open vSwitch (OVS).

You can create an NodeNetworkConfigurationPolicy (NNCP) object, part of the nmstate.io/v1 API group, to declaratively create the mapping. This API is provided by the NMState Operator. By using this API you can apply the bridge mapping to nodes that match your specified nodeSelector expression, such as node-role.kubernetes.io/worker: ''. With this declarative approach, the NMState Operator applies secondary network configuration to all nodes specified by the node selector automatically and transparently.

When attaching a secondary network, you can either use the existing br-ex bridge or create a new bridge. Which approach to use depends on your specific network infrastructure. Consider the following approaches:

  • If your nodes include only a single network interface, you must use the existing bridge. This network interface is owned and managed by OVN-Kubernetes and you must not remove it from the br-ex bridge or alter the interface configuration. If you remove or alter the network interface, your cluster network will stop working correctly.
  • If your nodes include several network interfaces, you can attach a different network interface to a new bridge, and use that for your secondary network. This approach provides for traffic isolation from your primary cluster network.

The localnet1 network is mapped to the br-ex bridge in the following example:

Example mapping for sharing a bridge

apiVersion: nmstate.io/v1
kind: NodeNetworkConfigurationPolicy
metadata:
  name: mapping
1 

spec:
  nodeSelector:
    node-role.kubernetes.io/worker: ''
2 

  desiredState:
    ovn:
      bridge-mappings:
      - localnet: localnet1
3 

        bridge: br-ex
4 

        state: present
5
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1 1
The name for the configuration object.
2
A node selector that specifies the nodes to apply the node network configuration policy to.
3
The name for the secondary network from which traffic is forwarded to the OVS bridge. This secondary network must match the name of the spec.config.name field of the NetworkAttachmentDefinition CRD that defines the OVN-Kubernetes secondary network.
4
The name of the OVS bridge on the node. This value is required only if you specify state: present.
5
The state for the mapping. Must be either present to add the bridge or absent to remove the bridge. The default value is present.

The following JSON example configures a localnet secondary network that is named localnet1. Note that the value for the mtu parameter must match the MTU value that was set for the secondary network interface that is mapped to the br-ex bridge interface. 

{
  "cniVersion": "0.3.1",
  "name": "ns1-localnet-network",
  "type": "ovn-k8s-cni-overlay",
  "topology":"localnet",
  "physicalNetworkName": "localnet1",
  "subnets": "202.10.130.112/28",
  "vlanID": 33,
  "mtu": 1500,
  "netAttachDefName": "ns1/localnet-network",
  "excludeSubnets": "10.100.200.0/29"
}
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In the following example, the localnet2 network interface is attached to the ovs-br1 bridge. Through this attachment, the network interface is available to the OVN-Kubernetes network plugin as a secondary network.

Example mapping for nodes with multiple interfaces

apiVersion: nmstate.io/v1
kind: NodeNetworkConfigurationPolicy
metadata:
  name: ovs-br1-multiple-networks
1 

spec:
  nodeSelector:
    node-role.kubernetes.io/worker: ''
2 

  desiredState:
    interfaces:
    - name: ovs-br1
3 

      description: |-
        A dedicated OVS bridge with eth1 as a port
        allowing all VLANs and untagged traffic
      type: ovs-bridge
      state: up
      bridge:
        allow-extra-patch-ports: true
        options:
          stp: false
          mcast-snooping-enable: true
4 

        port:
        - name: eth1
5 

    ovn:
      bridge-mappings:
      - localnet: localnet2
6 

        bridge: ovs-br1
7 

        state: present
8
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1
Specifies the name of the configuration object.
2
Specifies a node selector that identifies the nodes to which the node network configuration policy applies.
3
Specifies a new OVS bridge that operates separately from the default bridge used by OVN-Kubernetes for cluster traffic.
4
Specifies whether to enable multicast snooping. When enabled, multicast snooping prevents network devices from flooding multicast traffic to all network members. By default, an OVS bridge does not enable multicast snooping. The default value is false.
5
Specifies the network device on the host system to associate with the new OVS bridge.
6
Specifies the name of the secondary network that forwards traffic to the OVS bridge. This name must match the value of the spec.config.name field in the NetworkAttachmentDefinition CRD that defines the OVN-Kubernetes secondary network.
7
Specifies the name of the OVS bridge on the node. The value is required only when state: present is set.
8
Specifies the state of the mapping. Valid values are present to add the bridge or absent to remove the bridge. The default value is present.

The following JSON example configures a localnet secondary network that is named localnet2. Note that the value for the mtu parameter must match the MTU value that was set for the eth1 secondary network interface. 

{
  "cniVersion": "0.3.1",
  "name": "ns1-localnet-network",
  "type": "ovn-k8s-cni-overlay",
  "topology":"localnet",
  "physicalNetworkName": "localnet2",
  "subnets": "202.10.130.112/28",
  "vlanID": 33,
  "mtu": 1500,
  "netAttachDefName": "ns1/localnet-network",
  "excludeSubnets": "10.100.200.0/29"
}
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3.1.1.4.1. Configuration for a layer 2 switched topology

The switched (layer 2) topology networks interconnect the workloads through a cluster-wide logical switch. This configuration can be used for IPv6 and dual-stack deployments.

Note

Layer 2 switched topology networks only allow for the transfer of data packets between pods within a cluster.

The following JSON example configures a switched secondary network: 

{
  "cniVersion": "0.3.1",
  "name": "l2-network",
  "type": "ovn-k8s-cni-overlay",
  "topology":"layer2",
  "subnets": "10.100.200.0/24",
  "mtu": 1300,
  "netAttachDefName": "ns1/l2-network",
  "excludeSubnets": "10.100.200.0/29"
}
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3.1.1.5. Configuring pods for secondary networks

You must specify the secondary network attachments through the k8s.v1.cni.cncf.io/networks annotation.

The following example provisions a pod with two secondary attachments, one for each of the attachment configurations presented in this guide. 

apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: l2-network
  name: tinypod
  namespace: ns1
spec:
  containers:
  - args:
    - pause
    image: k8s.gcr.io/e2e-test-images/agnhost:2.36
    imagePullPolicy: IfNotPresent
    name: agnhost-container
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3.1.1.6. Configuring pods with a static IP address

The following example provisions a pod with a static IP address.

Note
  • You can specify the IP address for the secondary network attachment of a pod only when the secondary network attachment, a namespaced-scoped object, uses a layer 2 or localnet topology.
  • Specifying a static IP address for the pod is only possible when the attachment configuration does not feature subnets. 
apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
      {
        "name": "l2-network",
1 

        "mac": "02:03:04:05:06:07",
2 

        "interface": "myiface1",
3 

        "ips": [
          "192.0.2.20/24"
          ]
4 

      }
    ]'
  name: tinypod
  namespace: ns1
spec:
  containers:
  - args:
    - pause
    image: k8s.gcr.io/e2e-test-images/agnhost:2.36
    imagePullPolicy: IfNotPresent
    name: agnhost-container
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1
The name of the network. This value must be unique across all NetworkAttachmentDefinition CRDs.
2
The MAC address to be assigned for the interface.
3
The name of the network interface to be created for the pod.
4
The IP addresses to be assigned to the network interface.

3.2. Creating secondary networks with other CNI plugins

The specific configuration fields for secondary networks are described in the following sections.

3.2.1. Configuration for a bridge secondary network

The following object describes the configuration parameters for the Bridge CNI plugin:

Table 3.3. Bridge CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: bridge.

ipam

object

The configuration object for the IPAM CNI plugin. The plugin manages IP address assignment for the attachment definition.

bridge

string

Optional: Specify the name of the virtual bridge to use. If the bridge interface does not exist on the host, it is created. The default value is cni0.

ipMasq

boolean

Optional: Set to true to enable IP masquerading for traffic that leaves the virtual network. The source IP address for all traffic is rewritten to the bridge’s IP address. If the bridge does not have an IP address, this setting has no effect. The default value is false.

isGateway

boolean

Optional: Set to true to assign an IP address to the bridge. The default value is false.

isDefaultGateway

boolean

Optional: Set to true to configure the bridge as the default gateway for the virtual network. The default value is false. If isDefaultGateway is set to true, then isGateway is also set to true automatically.

forceAddress

boolean

Optional: Set to true to allow assignment of a previously assigned IP address to the virtual bridge. When set to false, if an IPv4 address or an IPv6 address from overlapping subsets is assigned to the virtual bridge, an error occurs. The default value is false.

hairpinMode

boolean

Optional: Set to true to allow the virtual bridge to send an Ethernet frame back through the virtual port it was received on. This mode is also known as reflective relay. The default value is false.

promiscMode

boolean

Optional: Set to true to enable promiscuous mode on the bridge. The default value is false.

vlan

string

Optional: Specify a virtual LAN (VLAN) tag as an integer value. By default, no VLAN tag is assigned.

preserveDefaultVlan

string

Optional: Indicates whether the default vlan must be preserved on the veth end connected to the bridge. Defaults to true.

vlanTrunk

list

Optional: Assign a VLAN trunk tag. The default value is none.

mtu

integer

Optional: Set the maximum transmission unit (MTU) to the specified value. The default value is automatically set by the kernel.

enabledad

boolean

Optional: Enables duplicate address detection for the container side veth. The default value is false.

macspoofchk

boolean

Optional: Enables mac spoof check, limiting the traffic originating from the container to the mac address of the interface. The default value is false.

Note

The VLAN parameter configures the VLAN tag on the host end of the veth and also enables the vlan_filtering feature on the bridge interface.

Note

To configure an uplink for an L2 network, you must allow the VLAN on the uplink interface by using the following command: 

$  bridge vlan add vid VLAN_ID dev DEV
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3.2.1.1. Bridge CNI plugin configuration example

The following example configures a secondary network named bridge-net: 

{
  "cniVersion": "0.3.1",
  "name": "bridge-net",
  "type": "bridge",
  "isGateway": true,
  "vlan": 2,
  "ipam": {
    "type": "dhcp"
    }
}
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3.2.2. Configuration for a host device secondary network

Note

Specify your network device by setting only one of the following parameters: device,hwaddr, kernelpath, or pciBusID.

The following object describes the configuration parameters for the host-device CNI plugin:

Table 3.4. Host device CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: host-device.

device

string

Optional: The name of the device, such as eth0.

hwaddr

string

Optional: The device hardware MAC address.

kernelpath

string

Optional: The Linux kernel device path, such as /sys/devices/pci0000:00/0000:00:1f.6.

pciBusID

string

Optional: The PCI address of the network device, such as 0000:00:1f.6.

3.2.2.1. host-device configuration example

The following example configures a secondary network named hostdev-net: 

{
  "cniVersion": "0.3.1",
  "name": "hostdev-net",
  "type": "host-device",
  "device": "eth1"
}
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3.2.3. Configuration for a VLAN secondary network

The following object describes the configuration parameters for the VLAN, vlan, CNI plugin:

Table 3.5. VLAN CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: vlan.

master

string

The Ethernet interface to associate with the network attachment. If a master is not specified, the interface for the default network route is used.

vlanId

integer

Set the ID of the vlan.

ipam

object

The configuration object for the IPAM CNI plugin. The plugin manages IP address assignment for the attachment definition.

mtu

integer

Optional: Set the maximum transmission unit (MTU) to the specified value. The default value is automatically set by the kernel.

dns

integer

Optional: DNS information to return. For example, a priority-ordered list of DNS nameservers.

linkInContainer

boolean

Optional: Specifies whether the master interface is in the container network namespace or the main network namespace. Set the value to true to request the use of a container namespace master interface.

Important

A NetworkAttachmentDefinition custom resource definition (CRD) with a vlan configuration can be used only on a single pod in a node because the CNI plugin cannot create multiple vlan subinterfaces with the same vlanId on the same master interface.

3.2.3.1. VLAN configuration example

The following example demonstrates a vlan configuration with a secondary network that is named vlan-net: 

{
  "name": "vlan-net",
  "cniVersion": "0.3.1",
  "type": "vlan",
  "master": "eth0",
  "mtu": 1500,
  "vlanId": 5,
  "linkInContainer": false,
  "ipam": {
      "type": "host-local",
      "subnet": "10.1.1.0/24"
  },
  "dns": {
      "nameservers": [ "10.1.1.1", "8.8.8.8" ]
  }
}
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3.2.4. Configuration for an IPVLAN secondary network

The following object describes the configuration parameters for the IPVLAN, ipvlan, CNI plugin:

Table 3.6. IPVLAN CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: ipvlan.

ipam

object

The configuration object for the IPAM CNI plugin. The plugin manages IP address assignment for the attachment definition. This is required unless the plugin is chained.

mode

string

Optional: The operating mode for the virtual network. The value must be l2, l3, or l3s. The default value is l2.

master

string

Optional: The Ethernet interface to associate with the network attachment. If a master is not specified, the interface for the default network route is used.

mtu

integer

Optional: Set the maximum transmission unit (MTU) to the specified value. The default value is automatically set by the kernel.

linkInContainer

boolean

Optional: Specifies whether the master interface is in the container network namespace or the main network namespace. Set the value to true to request the use of a container namespace master interface.

Important
  • The ipvlan object does not allow virtual interfaces to communicate with the master interface. Therefore the container is not able to reach the host by using the ipvlan interface. Be sure that the container joins a network that provides connectivity to the host, such as a network supporting the Precision Time Protocol (PTP).
  • A single master interface cannot simultaneously be configured to use both macvlan and ipvlan.
  • For IP allocation schemes that cannot be interface agnostic, the ipvlan plugin can be chained with an earlier plugin that handles this logic. If the master is omitted, then the previous result must contain a single interface name for the ipvlan plugin to enslave. If ipam is omitted, then the previous result is used to configure the ipvlan interface.

3.2.4.1. IPVLAN CNI plugin configuration example

The following example configures a secondary network named ipvlan-net: 

{
  "cniVersion": "0.3.1",
  "name": "ipvlan-net",
  "type": "ipvlan",
  "master": "eth1",
  "linkInContainer": false,
  "mode": "l3",
  "ipam": {
    "type": "static",
    "addresses": [
       {
         "address": "192.168.10.10/24"
       }
    ]
  }
}
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3.2.5. Configuration for a MACVLAN secondary network

The following object describes the configuration parameters for the MAC Virtual LAN (MACVLAN) Container Network Interface (CNI) plugin:

Table 3.7. MACVLAN CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: macvlan.

ipam

object

The configuration object for the IPAM CNI plugin. The plugin manages IP address assignment for the attachment definition.

mode

string

Optional: Configures traffic visibility on the virtual network. Must be either bridge, passthru, private, or vepa. If a value is not provided, the default value is bridge.

master

string

Optional: The host network interface to associate with the newly created macvlan interface. If a value is not specified, then the default route interface is used.

mtu

integer

Optional: The maximum transmission unit (MTU) to the specified value. The default value is automatically set by the kernel.

linkInContainer

boolean

Optional: Specifies whether the master interface is in the container network namespace or the main network namespace. Set the value to true to request the use of a container namespace master interface.

Note

If you specify the master key for the plugin configuration, use a different physical network interface than the one that is associated with your primary network plugin to avoid possible conflicts.

3.2.5.1. MACVLAN CNI plugin configuration example

The following example configures a secondary network named macvlan-net: 

{
  "cniVersion": "0.3.1",
  "name": "macvlan-net",
  "type": "macvlan",
  "master": "eth1",
  "linkInContainer": false,
  "mode": "bridge",
  "ipam": {
    "type": "dhcp"
    }
}
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3.2.6. Configuration for a TAP secondary network

The following object describes the configuration parameters for the TAP CNI plugin:

Table 3.8. TAP CNI plugin JSON configuration object
FieldTypeDescription

cniVersion

string

The CNI specification version. The 0.3.1 value is required.

name

string

The value for the name parameter you provided previously for the CNO configuration.

type

string

The name of the CNI plugin to configure: tap.

mac

string

Optional: Request the specified MAC address for the interface.

mtu

integer

Optional: Set the maximum transmission unit (MTU) to the specified value. The default value is automatically set by the kernel.

selinuxcontext

string

Optional: The SELinux context to associate with the tap device.

Note

The value system_u:system_r:container_t:s0 is required for OpenShift Container Platform.

multiQueue

boolean

Optional: Set to true to enable multi-queue.

owner

integer

Optional: The user owning the tap device.

group

integer

Optional: The group owning the tap device.

bridge

string

Optional: Set the tap device as a port of an already existing bridge.

3.2.6.1. Tap configuration example

The following example configures a secondary network named mynet: 

{
 "name": "mynet",
 "cniVersion": "0.3.1",
 "type": "tap",
 "mac": "00:11:22:33:44:55",
 "mtu": 1500,
 "selinuxcontext": "system_u:system_r:container_t:s0",
 "multiQueue": true,
 "owner": 0,
 "group": 0
 "bridge": "br1"
}
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3.2.6.2. Setting SELinux boolean for the TAP CNI plugin

To create the tap device with the container_t SELinux context, enable the container_use_devices boolean on the host by using the Machine Config Operator (MCO).

Prerequisites

  • You have installed the OpenShift CLI (oc).

Procedure

  1. Create a new YAML file named, such as setsebool-container-use-devices.yaml, with the following details: 

    apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 99-worker-setsebool
spec:
  config:
    ignition:
      version: 3.2.0
    systemd:
      units:
      - enabled: true
        name: setsebool.service
        contents: |
          [Unit]
          Description=Set SELinux boolean for the TAP CNI plugin
          Before=kubelet.service

          [Service]
          Type=oneshot
          ExecStart=/usr/sbin/setsebool container_use_devices=on
          RemainAfterExit=true

          [Install]
          WantedBy=multi-user.target graphical.target
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  2. Create the new MachineConfig object by running the following command: 

    $ oc apply -f setsebool-container-use-devices.yaml
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    Note

    Applying any changes to the MachineConfig object causes all affected nodes to gracefully reboot after the change is applied. This update can take some time to be applied.

  3. Verify the change is applied by running the following command: 

    $ oc get machineconfigpools
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    Expected output

    NAME        CONFIG                                                UPDATED   UPDATING   DEGRADED   MACHINECOUNT   READYMACHINECOUNT   UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
master      rendered-master-e5e0c8e8be9194e7c5a882e047379cfa      True      False      False      3              3                   3                     0                      7d2h
worker      rendered-worker-d6c9ca107fba6cd76cdcbfcedcafa0f2      True      False      False      3              3                   3                     0                      7d
    Copy to Clipboard

    Note

    All nodes should be in the updated and ready state.

3.2.7. Configuring routes using the route-override plugin on a secondary network

The following object describes the configuration parameters for the route-override CNI plugin:

Table 3.9. Route override CNI plugin JSON configuration object
FieldTypeDescription

type

string

The name of the CNI plugin to configure: route-override.

flushroutes

boolean

Optional: Set to true to flush any existing routes.

flushgateway

boolean

Optional: Set to true to flush the default route namely the gateway route.

delroutes

object

Optional: Specify the list of routes to delete from the container namespace.

addroutes

object

Optional: Specify the list of routes to add to the container namespace. Each route is a dictionary with dst and optional gw fields. If gw is omitted, the plugin uses the default gateway value.

skipcheck

boolean

Optional: Set this to true to skip the check command. By default, CNI plugins verify the network setup during the container lifecycle. When modifying routes dynamically with route-override, skipping this check ensures the final configuration reflects the updated routes.

3.2.7.1. Route-override plugin configuration example

The route-override CNI is a type of CNI that it is designed to be used when chained with a parent CNI. It does not operate independently, but relies on the parent CNI to first create the network interface and assign IP addresses before it can modify the routing rules.

The following example configures a secondary network named mymacvlan. The parent CNI creates a network interface attached to eth1 and assigns an IP address in the 192.168.1.0/24 range using host-local IPAM. The route-override CNI is then chained to the parent CNI and modifies the routing rules by flushing existing routes, deleting the route to 192.168.0.0/24, and adding a new route for 192.168.0.0/24 with a custom gateway. 

{
    "cniVersion": "0.3.0",
    "name": "mymacvlan",
    "plugins": [
        {
            "type": "macvlan",
1 

            "master": "eth1",
            "mode": "bridge",
            "ipam": {
                "type": "host-local",
                "subnet": "192.168.1.0/24"
            }
        },
        {
            "type": "route-override",
2 

            "flushroutes": true,
            "delroutes": [
                {
                    "dst": "192.168.0.0/24"
                }
            ],
            "addroutes": [
                {
                    "dst": "192.168.0.0/24",
                    "gw": "10.1.254.254"
                }
            ]
        }
    ]
}
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1
The parent CNI creates a network interface attached to eth1.
2
The chained route-override CNI modifies the routing rules.

3.3. Attaching a pod to a secondary network

As a cluster user you can attach a pod to a secondary network.

3.3.1. Adding a pod to a secondary network

You can add a pod to a secondary network. The pod continues to send normal cluster-related network traffic over the default network.

When a pod is created, a secondary networks is attached to the pod. However, if a pod already exists, you cannot attach a secondary network to it.

The pod must be in the same namespace as the secondary network.

Prerequisites

  • Install the OpenShift CLI (oc).
  • Log in to the cluster.

Procedure

  1. Add an annotation to the Pod object. Only one of the following annotation formats can be used:

    1. To attach a secondary network without any customization, add an annotation with the following format. Replace <network> with the name of the secondary network to associate with the pod: 

      metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: <network>[,<network>,...]
      1
      Copy to Clipboard
      1
      To specify more than one secondary network, separate each network with a comma. Do not include whitespace between the comma. If you specify the same secondary network multiple times, that pod will have multiple network interfaces attached to that network.

    2. To attach a secondary network with customizations, add an annotation with the following format: 

      metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: |-
      [
        {
          "name": "<network>",
      1 
      
          "namespace": "<namespace>",
      2 
      
          "default-route": ["<default-route>"]
      3 
      
        }
      ]
      Copy to Clipboard
      1
      Specify the name of the secondary network defined by a NetworkAttachmentDefinition object.
      2
      Specify the namespace where the NetworkAttachmentDefinition object is defined.
      3
      Optional: Specify an override for the default route, such as 192.168.17.1.

  2. To create the pod, enter the following command. Replace <name> with the name of the pod. 

    $ oc create -f <name>.yaml
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  3. Optional: To Confirm that the annotation exists in the Pod CR, enter the following command, replacing <name> with the name of the pod. 

    $ oc get pod <name> -o yaml
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    In the following example, the example-pod pod is attached to the net1 secondary network: 

    $ oc get pod example-pod -o yaml
apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: macvlan-bridge
    k8s.v1.cni.cncf.io/network-status: |-
    1 
    
      [{
          "name": "ovn-kubernetes",
          "interface": "eth0",
          "ips": [
              "10.128.2.14"
          ],
          "default": true,
          "dns": {}
      },{
          "name": "macvlan-bridge",
          "interface": "net1",
          "ips": [
              "20.2.2.100"
          ],
          "mac": "22:2f:60:a5:f8:00",
          "dns": {}
      }]
  name: example-pod
  namespace: default
spec:
  ...
status:
  ...
    Copy to Clipboard
    1
    The k8s.v1.cni.cncf.io/network-status parameter is a JSON array of objects. Each object describes the status of a secondary network attached to the pod. The annotation value is stored as a plain text value.

3.3.1.1. Specifying pod-specific addressing and routing options

When attaching a pod to a secondary network, you may want to specify further properties about that network in a particular pod. This allows you to change some aspects of routing, as well as specify static IP addresses and MAC addresses. To accomplish this, you can use the JSON formatted annotations.

Prerequisites

  • The pod must be in the same namespace as the secondary network.
  • Install the OpenShift CLI (oc).
  • You must log in to the cluster.

Procedure

To add a pod to a secondary network while specifying addressing and/or routing options, complete the following steps:

  1. Edit the Pod resource definition. If you are editing an existing Pod resource, run the following command to edit its definition in the default editor. Replace <name> with the name of the Pod resource to edit. 

    $ oc edit pod <name>
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  2. In the Pod resource definition, add the k8s.v1.cni.cncf.io/networks parameter to the pod metadata mapping. The k8s.v1.cni.cncf.io/networks accepts a JSON string of a list of objects that reference the name of NetworkAttachmentDefinition custom resource (CR) names in addition to specifying additional properties. 

    metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: '[<network>[,<network>,...]]'
    1
    Copy to Clipboard
    1
    Replace <network> with a JSON object as shown in the following examples. The single quotes are required.

  3. In the following example the annotation specifies which network attachment will have the default route, using the default-route parameter. 

    apiVersion: v1
kind: Pod
metadata:
  name: example-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
    {
      "name": "net1"
    },
    {
      "name": "net2",
    1 
    
      "default-route": ["192.0.2.1"]
    2 
    
    }]'
spec:
  containers:
  - name: example-pod
    command: ["/bin/bash", "-c", "sleep 2000000000000"]
    image: centos/tools
    Copy to Clipboard
    1
    The name key is the name of the secondary network to associate with the pod.
    2
    The default-route key specifies a value of a gateway for traffic to be routed over if no other routing entry is present in the routing table. If more than one default-route key is specified, this will cause the pod to fail to become active.

The default route will cause any traffic that is not specified in other routes to be routed to the gateway.

Important

Setting the default route to an interface other than the default network interface for OpenShift Container Platform may cause traffic that is anticipated for pod-to-pod traffic to be routed over another interface.

To verify the routing properties of a pod, the oc command may be used to execute the ip command within a pod. 

$ oc exec -it <pod_name> -- ip route
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Note

You may also reference the pod’s k8s.v1.cni.cncf.io/network-status to see which secondary network has been assigned the default route, by the presence of the default-route key in the JSON-formatted list of objects.

To set a static IP address or MAC address for a pod you can use the JSON formatted annotations. This requires you create networks that specifically allow for this functionality. This can be specified in a rawCNIConfig for the CNO.

  1. Edit the CNO CR by running the following command: 

    $ oc edit networks.operator.openshift.io cluster
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The following YAML describes the configuration parameters for the CNO:

Cluster Network Operator YAML configuration

name: <name>
1 

namespace: <namespace>
2 

rawCNIConfig: '{
3 

  ...
}'
type: Raw
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1
Specify a name for the secondary network attachment that you are creating. The name must be unique within the specified namespace.
2
Specify the namespace to create the network attachment in. If you do not specify a value, then the default namespace is used.
3
Specify the CNI plugin configuration in JSON format, which is based on the following template.

The following object describes the configuration parameters for utilizing static MAC address and IP address using the macvlan CNI plugin:

macvlan CNI plugin JSON configuration object using static IP and MAC address

{
  "cniVersion": "0.3.1",
  "name": "<name>",
1 

  "plugins": [{
2 

      "type": "macvlan",
      "capabilities": { "ips": true },
3 

      "master": "eth0",
4 

      "mode": "bridge",
      "ipam": {
        "type": "static"
      }
    }, {
      "capabilities": { "mac": true },
5 

      "type": "tuning"
    }]
}
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1
Specifies the name for the secondary network attachment to create. The name must be unique within the specified namespace.
2
Specifies an array of CNI plugin configurations. The first object specifies a macvlan plugin configuration and the second object specifies a tuning plugin configuration.
3
Specifies that a request is made to enable the static IP address functionality of the CNI plugin runtime configuration capabilities.
4
Specifies the interface that the macvlan plugin uses.
5
Specifies that a request is made to enable the static MAC address functionality of a CNI plugin.

The above network attachment can be referenced in a JSON formatted annotation, along with keys to specify which static IP and MAC address will be assigned to a given pod.

Edit the pod with: 

$ oc edit pod <name>
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macvlan CNI plugin JSON configuration object using static IP and MAC address

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
      {
        "name": "<name>",
1 

        "ips": [ "192.0.2.205/24" ],
2 

        "mac": "CA:FE:C0:FF:EE:00"
3 

      }
    ]'
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1
Use the <name> as provided when creating the rawCNIConfig above.
2
Provide an IP address including the subnet mask.
3
Provide the MAC address.
Note

Static IP addresses and MAC addresses do not have to be used at the same time, you may use them individually, or together.

To verify the IP address and MAC properties of a pod with secondary networks, use the oc command to execute the ip command within a pod. 

$ oc exec -it <pod_name> -- ip a
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3.4. Configuring multi-network policy

Administrators can use the MultiNetworkPolicy API to create multiple network policies that manage traffic for pods attached to secondary networks. For example, you can create policies that allow or deny traffic based on specific ports, IPs/ranges, or labels.

Multi-network policies can be used to manage traffic on secondary networks in the cluster. These policies cannot manage the default cluster network or primary network of user-defined networks.

As a cluster administrator, you can configure a multi-network policy for any of the following network types:

  • Single-Root I/O Virtualization (SR-IOV)
  • MAC Virtual Local Area Network (MacVLAN)
  • IP Virtual Local Area Network (IPVLAN)
  • Bond Container Network Interface (CNI) over SR-IOV
  • OVN-Kubernetes secondary networks
Note

Support for configuring multi-network policies for SR-IOV secondary networks is only supported with kernel network interface controllers (NICs). SR-IOV is not supported for Data Plane Development Kit (DPDK) applications.

3.4.1. Differences between multi-network policy and network policy

Although the MultiNetworkPolicy API implements the NetworkPolicy API, there are several important differences:

  • You must use the MultiNetworkPolicy API: 

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
    Copy to Clipboard
  • You must use the multi-networkpolicy resource name when using the CLI to interact with multi-network policies. For example, you can view a multi-network policy object with the oc get multi-networkpolicy <name> command where <name> is the name of a multi-network policy.

  • You can use the k8s.v1.cni.cncf.io/policy-for annotation on a MultiNetworkPolicy object to point to a NetworkAttachmentDefinition (NAD) custom resource (CR). The NAD CR defines the network to which the policy applies.

    Example multi-network policy that includes the k8s.v1.cni.cncf.io/policy-for annotation

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
    Copy to Clipboard

    where:

    <namespace_name>
    Specifies the namespace name.
    <network_name>
    Specifies the name of a network attachment definition.

3.4.2. Enabling multi-network policy for the cluster

As a cluster administrator, you can enable multi-network policy support on your cluster.

Prerequisites

  • Install the OpenShift CLI (oc).
  • Log in to the cluster with a user with cluster-admin privileges.

Procedure

  1. Create the multinetwork-enable-patch.yaml file with the following YAML: 

    apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  useMultiNetworkPolicy: true
    Copy to Clipboard

  2. Configure the cluster to enable multi-network policy: 

    $ oc patch network.operator.openshift.io cluster --type=merge --patch-file=multinetwork-enable-patch.yaml
    Copy to Clipboard

    Example output

    network.operator.openshift.io/cluster patched
    Copy to Clipboard

3.4.3. Supporting multi-network policies in IPv6 networks

The ICMPv6 Neighbor Discovery Protocol (NDP) is a set of messages and processes that enable devices to discover and maintain information about neighboring nodes. NDP plays a crucial role in IPv6 networks, facilitating the interaction between devices on the same link.

The Cluster Network Operator (CNO) deploys the iptables implementation of multi-network policy when the useMultiNetworkPolicy parameter is set to true.

To support multi-network policies in IPv6 networks the Cluster Network Operator deploys the following set of rules in every pod affected by a multi-network policy:

Multi-network policy custom rules

kind: ConfigMap
apiVersion: v1
metadata:
  name: multi-networkpolicy-custom-rules
  namespace: openshift-multus
data:

  custom-v6-rules.txt: |
    # accept NDP
    -p icmpv6 --icmpv6-type neighbor-solicitation -j ACCEPT
1 

    -p icmpv6 --icmpv6-type neighbor-advertisement -j ACCEPT
2 

    # accept RA/RS
    -p icmpv6 --icmpv6-type router-solicitation -j ACCEPT
3 

    -p icmpv6 --icmpv6-type router-advertisement -j ACCEPT
4
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1
This rule allows incoming ICMPv6 neighbor solicitation messages, which are part of the neighbor discovery protocol (NDP). These messages help determine the link-layer addresses of neighboring nodes.
2
This rule allows incoming ICMPv6 neighbor advertisement messages, which are part of NDP and provide information about the link-layer address of the sender.
3
This rule permits incoming ICMPv6 router solicitation messages. Hosts use these messages to request router configuration information.
4
This rule allows incoming ICMPv6 router advertisement messages, which give configuration information to hosts.
Note

You cannot edit these predefined rules.

These rules collectively enable essential ICMPv6 traffic for correct network functioning, including address resolution and router communication in an IPv6 environment. With these rules in place and a multi-network policy denying traffic, applications are not expected to experience connectivity issues.

3.4.4. Working with multi-network policy

As a cluster administrator, you can create, edit, view, and delete multi-network policies.

3.4.4.1. Prerequisites

  • You have enabled multi-network policy support for your cluster.

3.4.4.2. Creating a multi-network policy using the CLI

To define granular rules describing ingress or egress network traffic allowed for namespaces in your cluster, you can create a multi-network policy.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace that the multi-network policy applies to.

Procedure

  1. Create a policy rule:

    1. Create a <policy_name>.yaml file: 

      $ touch <policy_name>.yaml
      Copy to Clipboard

      where:

      <policy_name>
      Specifies the multi-network policy file name.

    2. Define a multi-network policy in the file that you just created, such as in the following examples:

      Deny ingress from all pods in all namespaces

      This is a fundamental policy, blocking all cross-pod networking other than cross-pod traffic allowed by the configuration of other Network Policies. 

      apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: deny-by-default
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  ingress: []
      Copy to Clipboard

      where:

      <network_name>
      Specifies the name of a network attachment definition.

      Allow ingress from all pods in the same namespace

      apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: allow-same-namespace
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector:
  ingress:
  - from:
    - podSelector: {}
      Copy to Clipboard

      where:

      <network_name>
      Specifies the name of a network attachment definition.

      Allow ingress traffic to one pod from a particular namespace

      This policy allows traffic to pods labelled pod-a from pods running in namespace-y. 

      apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: allow-traffic-pod
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector:
   matchLabels:
      pod: pod-a
  policyTypes:
  - Ingress
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
           kubernetes.io/metadata.name: namespace-y
      Copy to Clipboard

      where:

      <network_name>
      Specifies the name of a network attachment definition.

      Restrict traffic to a service

      This policy when applied ensures every pod with both labels app=bookstore and role=api can only be accessed by pods with label app=bookstore. In this example the application could be a REST API server, marked with labels app=bookstore and role=api.

      This example addresses the following use cases:

      • Restricting the traffic to a service to only the other microservices that need to use it.

      • Restricting the connections to a database to only permit the application using it. 

        apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: api-allow
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector:
    matchLabels:
      app: bookstore
      role: api
  ingress:
  - from:
      - podSelector:
          matchLabels:
            app: bookstore
        Copy to Clipboard

        where:

        <network_name>
        Specifies the name of a network attachment definition.

  2. To create the multi-network policy object, enter the following command: 

    $ oc apply -f <policy_name>.yaml -n <namespace>
    Copy to Clipboard

    where:

    <policy_name>
    Specifies the multi-network policy file name.
    <namespace>
    Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/deny-by-default created
    Copy to Clipboard

Note

If you log in to the web console with cluster-admin privileges, you have a choice of creating a network policy in any namespace in the cluster directly in YAML or from a form in the web console.

3.4.4.3. Editing a multi-network policy

You can edit a multi-network policy in a namespace.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace where the multi-network policy exists.

Procedure

  1. Optional: To list the multi-network policy objects in a namespace, enter the following command: 

    $ oc get multi-networkpolicy
    Copy to Clipboard

    where:

    <namespace>
    Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.

  2. Edit the multi-network policy object.

    • If you saved the multi-network policy definition in a file, edit the file and make any necessary changes, and then enter the following command. 

      $ oc apply -n <namespace> -f <policy_file>.yaml
      Copy to Clipboard

      where:

      <namespace>
      Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.
      <policy_file>
      Specifies the name of the file containing the network policy.

    • If you need to update the multi-network policy object directly, enter the following command: 

      $ oc edit multi-networkpolicy <policy_name> -n <namespace>
      Copy to Clipboard

      where:

      <policy_name>
      Specifies the name of the network policy.
      <namespace>
      Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.

  3. Confirm that the multi-network policy object is updated. 

    $ oc describe multi-networkpolicy <policy_name> -n <namespace>
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    where:

    <policy_name>
    Specifies the name of the multi-network policy.
    <namespace>
    Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.
Note

If you log in to the web console with cluster-admin privileges, you have a choice of editing a network policy in any namespace in the cluster directly in YAML or from the policy in the web console through the Actions menu.

3.4.4.4. Viewing multi-network policies using the CLI

You can examine the multi-network policies in a namespace.

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace where the multi-network policy exists.

Procedure

  • List multi-network policies in a namespace:

    • To view multi-network policy objects defined in a namespace, enter the following command: 

      $ oc get multi-networkpolicy
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    • Optional: To examine a specific multi-network policy, enter the following command: 

      $ oc describe multi-networkpolicy <policy_name> -n <namespace>
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      where:

      <policy_name>
      Specifies the name of the multi-network policy to inspect.
      <namespace>
      Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.
Note

If you log in to the web console with cluster-admin privileges, you have a choice of viewing a network policy in any namespace in the cluster directly in YAML or from a form in the web console.

3.4.4.5. Deleting a multi-network policy using the CLI

You can delete a multi-network policy in a namespace.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace where the multi-network policy exists.

Procedure

  • To delete a multi-network policy object, enter the following command: 

    $ oc delete multi-networkpolicy <policy_name> -n <namespace>
    Copy to Clipboard

    where:

    <policy_name>
    Specifies the name of the multi-network policy.
    <namespace>
    Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/default-deny deleted
    Copy to Clipboard

Note

If you log in to the web console with cluster-admin privileges, you have a choice of deleting a network policy in any namespace in the cluster directly in YAML or from the policy in the web console through the Actions menu.

3.4.4.6. Creating a default deny all multi-network policy

This policy blocks all cross-pod networking other than network traffic allowed by the configuration of other deployed network policies and traffic between host-networked pods. This procedure enforces a strong deny policy by applying a deny-by-default policy in the my-project namespace.

Warning

Without configuring a NetworkPolicy custom resource (CR) that allows traffic communication, the following policy might cause communication problems across your cluster.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace that the multi-network policy applies to.

Procedure

  1. Create the following YAML that defines a deny-by-default policy to deny ingress from all pods in all namespaces. Save the YAML in the deny-by-default.yaml file: 

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: deny-by-default
  namespace: my-project
    1 
    
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
    2 
    
spec:
  podSelector: {}
    3 
    
  policyTypes:
    4 
    
  - Ingress
    5 
    
  ingress: []
    6
    Copy to Clipboard
    1
    Specifies the namespace in which to deploy the policy. For example, the my-project namespace.
    2
    Specifies the name of namespace project followed by the network attachment definition name.
    3
    If this field is empty, the configuration matches all the pods. Therefore, the policy applies to all pods in the my-project namespace.
    4
    Specifies a list of rule types that the NetworkPolicy relates to.
    5
    Specifies Ingress only policyTypes.
    6
    Specifies ingress rules. If not specified, all incoming traffic is dropped to all pods.

  2. Apply the policy by entering the following command: 

    $ oc apply -f deny-by-default.yaml
    Copy to Clipboard

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/deny-by-default created
    Copy to Clipboard

3.4.4.7. Creating a multi-network policy to allow traffic from external clients

With the deny-by-default policy in place you can proceed to configure a policy that allows traffic from external clients to a pod with the label app=web.

Note

If you log in with a user with the cluster-admin role, then you can create a network policy in any namespace in the cluster.

Follow this procedure to configure a policy that allows external service from the public Internet directly or by using a Load Balancer to access the pod. Traffic is only allowed to a pod with the label app=web.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace that the multi-network policy applies to.

Procedure

  1. Create a policy that allows traffic from the public Internet directly or by using a load balancer to access the pod. Save the YAML in the web-allow-external.yaml file: 

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: web-allow-external
  namespace: default
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  policyTypes:
  - Ingress
  podSelector:
    matchLabels:
      app: web
  ingress:
    - {}
    Copy to Clipboard

  2. Apply the policy by entering the following command: 

    $ oc apply -f web-allow-external.yaml
    Copy to Clipboard

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/web-allow-external created
    Copy to Clipboard

    This policy allows traffic from all resources, including external traffic as illustrated in the following diagram:

Allow traffic from external clients
View larger image
Allow traffic from external clients

3.4.4.8. Creating a multi-network policy allowing traffic to an application from all namespaces

Note

If you log in with a user with the cluster-admin role, then you can create a network policy in any namespace in the cluster.

Follow this procedure to configure a policy that allows traffic from all pods in all namespaces to a particular application.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace that the multi-network policy applies to.

Procedure

  1. Create a policy that allows traffic from all pods in all namespaces to a particular application. Save the YAML in the web-allow-all-namespaces.yaml file: 

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: web-allow-all-namespaces
  namespace: default
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector:
    matchLabels:
      app: web
    1 
    
  policyTypes:
  - Ingress
  ingress:
  - from:
    - namespaceSelector: {}
    2
    Copy to Clipboard
    1
    Applies the policy only to app:web pods in default namespace.
    2
    Selects all pods in all namespaces.
    Note

    By default, if you omit specifying a namespaceSelector it does not select any namespaces, which means the policy allows traffic only from the namespace the network policy is deployed to.

  2. Apply the policy by entering the following command: 

    $ oc apply -f web-allow-all-namespaces.yaml
    Copy to Clipboard

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/web-allow-all-namespaces created
    Copy to Clipboard

Verification

  1. Start a web service in the default namespace by entering the following command: 

    $ oc run web --namespace=default --image=nginx --labels="app=web" --expose --port=80
    Copy to Clipboard

  2. Run the following command to deploy an alpine image in the secondary namespace and to start a shell: 

    $ oc run test-$RANDOM --namespace=secondary --rm -i -t --image=alpine -- sh
    Copy to Clipboard

  3. Run the following command in the shell and observe that the request is allowed: 

    # wget -qO- --timeout=2 http://web.default
    Copy to Clipboard

    Expected output

    <!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
    Copy to Clipboard

3.4.4.9. Creating a multi-network policy allowing traffic to an application from a namespace

Note

If you log in with a user with the cluster-admin role, then you can create a network policy in any namespace in the cluster.

Follow this procedure to configure a policy that allows traffic to a pod with the label app=web from a particular namespace. You might want to do this to:

  • Restrict traffic to a production database only to namespaces where production workloads are deployed.
  • Enable monitoring tools deployed to a particular namespace to scrape metrics from the current namespace.

Prerequisites

  • Your cluster uses a network plugin that supports NetworkPolicy objects, such as the OVN-Kubernetes network plugin, with mode: NetworkPolicy set.
  • You installed the OpenShift CLI (oc).
  • You are logged in to the cluster with a user with cluster-admin privileges.
  • You are working in the namespace that the multi-network policy applies to.

Procedure

  1. Create a policy that allows traffic from all pods in a particular namespaces with a label purpose=production. Save the YAML in the web-allow-prod.yaml file: 

    apiVersion: k8s.cni.cncf.io/v1beta1
kind: MultiNetworkPolicy
metadata:
  name: web-allow-prod
  namespace: default
  annotations:
    k8s.v1.cni.cncf.io/policy-for:<namespace_name>/<network_name>
spec:
  podSelector:
    matchLabels:
      app: web
    1 
    
  policyTypes:
  - Ingress
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          purpose: production
    2
    Copy to Clipboard
    1
    Applies the policy only to app:web pods in the default namespace.
    2
    Restricts traffic to only pods in namespaces that have the label purpose=production.

  2. Apply the policy by entering the following command: 

    $ oc apply -f web-allow-prod.yaml
    Copy to Clipboard

    Example output

    multinetworkpolicy.k8s.cni.cncf.io/web-allow-prod created
    Copy to Clipboard

Verification

  1. Start a web service in the default namespace by entering the following command: 

    $ oc run web --namespace=default --image=nginx --labels="app=web" --expose --port=80
    Copy to Clipboard

  2. Run the following command to create the prod namespace: 

    $ oc create namespace prod
    Copy to Clipboard

  3. Run the following command to label the prod namespace: 

    $ oc label namespace/prod purpose=production
    Copy to Clipboard

  4. Run the following command to create the dev namespace: 

    $ oc create namespace dev
    Copy to Clipboard

  5. Run the following command to label the dev namespace: 

    $ oc label namespace/dev purpose=testing
    Copy to Clipboard

  6. Run the following command to deploy an alpine image in the dev namespace and to start a shell: 

    $ oc run test-$RANDOM --namespace=dev --rm -i -t --image=alpine -- sh
    Copy to Clipboard

  7. Run the following command in the shell and observe that the request is blocked: 

    # wget -qO- --timeout=2 http://web.default
    Copy to Clipboard

    Expected output

    wget: download timed out
    Copy to Clipboard

  8. Run the following command to deploy an alpine image in the prod namespace and start a shell: 

    $ oc run test-$RANDOM --namespace=prod --rm -i -t --image=alpine -- sh
    Copy to Clipboard

  9. Run the following command in the shell and observe that the request is allowed: 

    # wget -qO- --timeout=2 http://web.default
    Copy to Clipboard

    Expected output

    <!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
    Copy to Clipboard

3.5. Removing a pod from a secondary network

As a cluster user you can remove a pod from a secondary network.

3.5.1. Removing a pod from a secondary network

You can remove a pod from a secondary network only by deleting the pod.

Prerequisites

  • A secondary network is attached to the pod.
  • Install the OpenShift CLI (oc).
  • Log in to the cluster.

Procedure

  • To delete the pod, enter the following command: 

    $ oc delete pod <name> -n <namespace>
    Copy to Clipboard
    • <name> is the name of the pod.
    • <namespace> is the namespace that contains the pod.

3.6. Editing a secondary network

As a cluster administrator you can modify the configuration for an existing secondary network.

3.6.1. Modifying a secondary network attachment definition

As a cluster administrator, you can make changes to an existing secondary network. Any existing pods attached to the secondary network will not be updated.

Prerequisites

  • You have configured a secondary network for your cluster.
  • Install the OpenShift CLI (oc).
  • Log in as a user with cluster-admin privileges.

Procedure

To edit a secondary network for your cluster, complete the following steps:

  1. Run the following command to edit the Cluster Network Operator (CNO) CR in your default text editor: 

    $ oc edit networks.operator.openshift.io cluster
    Copy to Clipboard
  2. In the additionalNetworks collection, update the secondary network with your changes.
  3. Save your changes and quit the text editor to commit your changes.

  4. Optional: Confirm that the CNO updated the NetworkAttachmentDefinition object by running the following command. Replace <network-name> with the name of the secondary network to display. There might be a delay before the CNO updates the NetworkAttachmentDefinition object to reflect your changes. 

    $ oc get network-attachment-definitions <network-name> -o yaml
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    For example, the following console output displays a NetworkAttachmentDefinition object that is named net1: 

    $ oc get network-attachment-definitions net1 -o go-template='{{printf "%s\n" .spec.config}}'
{ "cniVersion": "0.3.1", "type": "macvlan",
"master": "ens5",
"mode": "bridge",
"ipam":       {"type":"static","routes":[{"dst":"0.0.0.0/0","gw":"10.128.2.1"}],"addresses":[{"address":"10.128.2.100/23","gateway":"10.128.2.1"}],"dns":{"nameservers":["172.30.0.10"],"domain":"us-west-2.compute.internal","search":["us-west-2.compute.internal"]}} }
    Copy to Clipboard

3.7. Configuring IP address assignment on secondary networks

The following sections give instructions and information for how to configure IP address assignments for secondary networks.

3.7.1. Configuration of IP address assignment for a network attachment

For secondary networks, IP addresses can be assigned using an IP Address Management (IPAM) CNI plugin, which supports various assignment methods, including Dynamic Host Configuration Protocol (DHCP) and static assignment.

The DHCP IPAM CNI plugin responsible for dynamic assignment of IP addresses operates with two distinct components:

  • CNI Plugin: Responsible for integrating with the Kubernetes networking stack to request and release IP addresses.
  • DHCP IPAM CNI Daemon: A listener for DHCP events that coordinates with existing DHCP servers in the environment to handle IP address assignment requests. This daemon is not a DHCP server itself.

For networks requiring type: dhcp in their IPAM configuration, ensure the following:

  • A DHCP server is available and running in the environment. The DHCP server is external to the cluster and is expected to be part of the customer’s existing network infrastructure.
  • The DHCP server is appropriately configured to serve IP addresses to the nodes.

In cases where a DHCP server is unavailable in the environment, it is recommended to use the Whereabouts IPAM CNI plugin instead. The Whereabouts CNI provides similar IP address management capabilities without the need for an external DHCP server.

Note

Use the Whereabouts CNI plugin when there is no external DHCP server or where static IP address management is preferred. The Whereabouts plugin includes a reconciler daemon to manage stale IP address allocations.

A DHCP lease must be periodically renewed throughout the container’s lifetime, so a separate daemon, the DHCP IPAM CNI Daemon, is required. To deploy the DHCP IPAM CNI daemon, modify the Cluster Network Operator (CNO) configuration to trigger the deployment of this daemon as part of the secondary network setup.

3.7.1.1. Static IP address assignment configuration

The following table describes the configuration for static IP address assignment:

Table 3.10. ipam static configuration object
FieldTypeDescription

type

string

The IPAM address type. The value static is required.

addresses

array

An array of objects specifying IP addresses to assign to the virtual interface. Both IPv4 and IPv6 IP addresses are supported.

routes

array

An array of objects specifying routes to configure inside the pod.

dns

array

Optional: An array of objects specifying the DNS configuration.

The addresses array requires objects with the following fields:

Table 3.11. ipam.addresses[] array
FieldTypeDescription

address

string

An IP address and network prefix that you specify. For example, if you specify 10.10.21.10/24, then the secondary network is assigned an IP address of 10.10.21.10 and the netmask is 255.255.255.0.

gateway

string

The default gateway to route egress network traffic to.

Table 3.12. ipam.routes[] array
FieldTypeDescription

dst

string

The IP address range in CIDR format, such as 192.168.17.0/24 or 0.0.0.0/0 for the default route.

gw

string

The gateway where network traffic is routed.

Table 3.13. ipam.dns object
FieldTypeDescription

nameservers

array

An array of one or more IP addresses for to send DNS queries to.

domain

array

The default domain to append to a hostname. For example, if the domain is set to example.com, a DNS lookup query for example-host is rewritten as example-host.example.com.

search

array

An array of domain names to append to an unqualified hostname, such as example-host, during a DNS lookup query.

Static IP address assignment configuration example

{
  "ipam": {
    "type": "static",
      "addresses": [
        {
          "address": "191.168.1.7/24"
        }
      ]
  }
}
Copy to Clipboard

3.7.1.2. Dynamic IP address (DHCP) assignment configuration

A pod obtains its original DHCP lease when it is created. The lease must be periodically renewed by a minimal DHCP server deployment running on the cluster.

Important

For an Ethernet network attachment, the SR-IOV Network Operator does not create a DHCP server deployment; the Cluster Network Operator is responsible for creating the minimal DHCP server deployment.

To trigger the deployment of the DHCP server, you must create a shim network attachment by editing the Cluster Network Operator configuration, as in the following example:

Example shim network attachment definition

apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  additionalNetworks:
  - name: dhcp-shim
    namespace: default
    type: Raw
    rawCNIConfig: |-
      {
        "name": "dhcp-shim",
        "cniVersion": "0.3.1",
        "type": "bridge",
        "ipam": {
          "type": "dhcp"
        }
      }
  # ...
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The following table describes the configuration parameters for dynamic IP address address assignment with DHCP.

Table 3.14. ipam DHCP configuration object
FieldTypeDescription

type

string

The IPAM address type. The value dhcp is required.

The following JSON example describes the configuration p for dynamic IP address address assignment with DHCP.

Dynamic IP address (DHCP) assignment configuration example

{
  "ipam": {
    "type": "dhcp"
  }
}
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3.7.1.3. Dynamic IP address assignment configuration with Whereabouts

The Whereabouts CNI plugin allows the dynamic assignment of an IP address to a secondary network without the use of a DHCP server.

The Whereabouts CNI plugin also supports overlapping IP address ranges and configuration of the same CIDR range multiple times within separate NetworkAttachmentDefinition CRDs. This provides greater flexibility and management capabilities in multi-tenant environments.

3.7.1.3.1. Dynamic IP address configuration objects

The following table describes the configuration objects for dynamic IP address assignment with Whereabouts:

Table 3.15. ipam whereabouts configuration object
FieldTypeDescription

type

string

The IPAM address type. The value whereabouts is required.

range

string

An IP address and range in CIDR notation. IP addresses are assigned from within this range of addresses.

exclude

array

Optional: A list of zero or more IP addresses and ranges in CIDR notation. IP addresses within an excluded address range are not assigned.

network_name

string

Optional: Helps ensure that each group or domain of pods gets its own set of IP addresses, even if they share the same range of IP addresses. Setting this field is important for keeping networks separate and organized, notably in multi-tenant environments.

3.7.1.3.2. Dynamic IP address assignment configuration that uses Whereabouts

The following example shows a dynamic address assignment configuration that uses Whereabouts:

Whereabouts dynamic IP address assignment

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/27",
    "exclude": [
       "192.0.2.192/30",
       "192.0.2.196/32"
    ]
  }
}
Copy to Clipboard

3.7.1.3.3. Dynamic IP address assignment that uses Whereabouts with overlapping IP address ranges

The following example shows a dynamic IP address assignment that uses overlapping IP address ranges for multi-tenant networks.

NetworkAttachmentDefinition 1

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/29",
    "network_name": "example_net_common",
1 

  }
}
Copy to Clipboard

1
Optional. If set, must match the network_name of NetworkAttachmentDefinition 2.

NetworkAttachmentDefinition 2

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/24",
    "network_name": "example_net_common",
1 

  }
}
Copy to Clipboard

1
Optional. If set, must match the network_name of NetworkAttachmentDefinition 1.

3.7.1.4. Creating a whereabouts-reconciler daemon set

The Whereabouts reconciler is responsible for managing dynamic IP address assignments for the pods within a cluster by using the Whereabouts IP Address Management (IPAM) solution. It ensures that each pod gets a unique IP address from the specified IP address range. It also handles IP address releases when pods are deleted or scaled down.

Note

You can also use a NetworkAttachmentDefinition custom resource definition (CRD) for dynamic IP address assignment.

The whereabouts-reconciler daemon set is automatically created when you configure a secondary network through the Cluster Network Operator. It is not automatically created when you configure a secondary network from a YAML manifest.

To trigger the deployment of the whereabouts-reconciler daemon set, you must manually create a whereabouts-shim network attachment by editing the Cluster Network Operator custom resource (CR) file.

Use the following procedure to deploy the whereabouts-reconciler daemon set.

Procedure

  1. Edit the Network.operator.openshift.io custom resource (CR) by running the following command: 

    $ oc edit network.operator.openshift.io cluster
    Copy to Clipboard

  2. Include the additionalNetworks section shown in this example YAML extract within the spec definition of the custom resource (CR): 

    apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
# ...
spec:
  additionalNetworks:
  - name: whereabouts-shim
    namespace: default
    rawCNIConfig: |-
      {
       "name": "whereabouts-shim",
       "cniVersion": "0.3.1",
       "type": "bridge",
       "ipam": {
         "type": "whereabouts"
       }
      }
    type: Raw
# ...
    Copy to Clipboard
  3. Save the file and exit the text editor.

  4. Verify that the whereabouts-reconciler daemon set deployed successfully by running the following command: 

    $ oc get all -n openshift-multus | grep whereabouts-reconciler
    Copy to Clipboard

    Example output

    pod/whereabouts-reconciler-jnp6g 1/1 Running 0 6s
pod/whereabouts-reconciler-k76gg 1/1 Running 0 6s
pod/whereabouts-reconciler-k86t9 1/1 Running 0 6s
pod/whereabouts-reconciler-p4sxw 1/1 Running 0 6s
pod/whereabouts-reconciler-rvfdv 1/1 Running 0 6s
pod/whereabouts-reconciler-svzw9 1/1 Running 0 6s
daemonset.apps/whereabouts-reconciler 6 6 6 6 6 kubernetes.io/os=linux 6s
    Copy to Clipboard

3.7.1.5. Configuring the Whereabouts IP reconciler schedule

The Whereabouts IPAM CNI plugin runs the IP reconciler daily. This process cleans up any stranded IP allocations that might result in exhausting IPs and therefore prevent new pods from getting an IP allocated to them.

Use this procedure to change the frequency at which the IP reconciler runs.

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.
  • You have deployed the whereabouts-reconciler daemon set, and the whereabouts-reconciler pods are up and running.

Procedure

  1. Run the following command to create a ConfigMap object named whereabouts-config in the openshift-multus namespace with a specific cron expression for the IP reconciler: 

    $ oc create configmap whereabouts-config -n openshift-multus --from-literal=reconciler_cron_expression="*/15 * * * *"
    Copy to Clipboard

    This cron expression indicates the IP reconciler runs every 15 minutes. Adjust the expression based on your specific requirements.

    Note

    The whereabouts-reconciler daemon set can only consume a cron expression pattern that includes five asterisks. The sixth, which is used to denote seconds, is currently not supported.

  2. Retrieve information about resources related to the whereabouts-reconciler daemon set and pods within the openshift-multus namespace by running the following command: 

    $ oc get all -n openshift-multus | grep whereabouts-reconciler
    Copy to Clipboard

    Example output

    pod/whereabouts-reconciler-2p7hw                   1/1     Running   0             4m14s
pod/whereabouts-reconciler-76jk7                   1/1     Running   0             4m14s
pod/whereabouts-reconciler-94zw6                   1/1     Running   0             4m14s
pod/whereabouts-reconciler-mfh68                   1/1     Running   0             4m14s
pod/whereabouts-reconciler-pgshz                   1/1     Running   0             4m14s
pod/whereabouts-reconciler-xn5xz                   1/1     Running   0             4m14s
daemonset.apps/whereabouts-reconciler          6         6         6       6            6           kubernetes.io/os=linux   4m16s
    Copy to Clipboard

  3. Run the following command to verify that the whereabouts-reconciler pod runs the IP reconciler with the configured interval: 

    $ oc -n openshift-multus logs whereabouts-reconciler-2p7hw
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    Example output

    2024-02-02T16:33:54Z [debug] event not relevant: "/cron-schedule/..2024_02_02_16_33_54.1375928161": CREATE
2024-02-02T16:33:54Z [debug] event not relevant: "/cron-schedule/..2024_02_02_16_33_54.1375928161": CHMOD
2024-02-02T16:33:54Z [debug] event not relevant: "/cron-schedule/..data_tmp": RENAME
2024-02-02T16:33:54Z [verbose] using expression: */15 * * * *
2024-02-02T16:33:54Z [verbose] configuration updated to file "/cron-schedule/..data". New cron expression: */15 * * * *
2024-02-02T16:33:54Z [verbose] successfully updated CRON configuration id "00c2d1c9-631d-403f-bb86-73ad104a6817" - new cron expression: */15 * * * *
2024-02-02T16:33:54Z [debug] event not relevant: "/cron-schedule/config": CREATE
2024-02-02T16:33:54Z [debug] event not relevant: "/cron-schedule/..2024_02_02_16_26_17.3874177937": REMOVE
2024-02-02T16:45:00Z [verbose] starting reconciler run
2024-02-02T16:45:00Z [debug] NewReconcileLooper - inferred connection data
2024-02-02T16:45:00Z [debug] listing IP pools
2024-02-02T16:45:00Z [debug] no IP addresses to cleanup
2024-02-02T16:45:00Z [verbose] reconciler success
    Copy to Clipboard

3.7.1.6. Creating a configuration for assignment of dual-stack IP addresses dynamically

Dual-stack IP address assignment can be configured with the ipRanges parameter for:

  • IPv4 addresses
  • IPv6 addresses
  • multiple IP address assignment

Procedure

  1. Set type to whereabouts.

  2. Use ipRanges to allocate IP addresses as shown in the following example: 

    cniVersion: operator.openshift.io/v1
kind: Network
=metadata:
  name: cluster
spec:
  additionalNetworks:
  - name: whereabouts-shim
    namespace: default
    type: Raw
    rawCNIConfig: |-
      {
       "name": "whereabouts-dual-stack",
       "cniVersion": "0.3.1,
       "type": "bridge",
       "ipam": {
         "type": "whereabouts",
         "ipRanges": [
                  {"range": "192.168.10.0/24"},
                  {"range": "2001:db8::/64"}
              ]
       }
      }
    Copy to Clipboard
  3. Attach network to a pod. For more information, see "Adding a pod to a secondary network".
  4. Verify that all IP addresses are assigned.

  5. Run the following command to ensure the IP addresses are assigned as metadata. 

    $ oc exec -it mypod -- ip a
    Copy to Clipboard

3.8. Configuring the master interface in the container network namespace

The following section provides instructions and information for how to create and manage a MAC-VLAN, IP-VLAN, and VLAN subinterface based on a master interface.

3.8.1. About configuring the master interface in the container network namespace

You can create a MAC-VLAN, an IP-VLAN, or a VLAN subinterface that is based on a master interface that exists in a container namespace. You can also create a master interface as part of the pod network configuration in a separate network attachment definition CRD.

To use a container namespace master interface, you must specify true for the linkInContainer parameter that exists in the subinterface configuration of the NetworkAttachmentDefinition CRD.

3.8.1.1. Creating multiple VLANs on SR-IOV VFs

An example use case for utilizing this feature is to create multiple VLANs based on SR-IOV VFs. To do so, begin by creating an SR-IOV network and then define the network attachments for the VLAN interfaces.

The following example shows how to configure the setup illustrated in this diagram.

Figure 3.1. Creating VLANs

Creating VLANs
View larger image
Creating VLANs

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.
  • You have installed the SR-IOV Network Operator.

Procedure

  1. Create a dedicated container namespace where you want to deploy your pod by using the following command: 

    $ oc new-project test-namespace
    Copy to Clipboard

  2. Create an SR-IOV node policy:

    1. Create an SriovNetworkNodePolicy object, and then save the YAML in the sriov-node-network-policy.yaml file: 

      apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
 name: sriovnic
 namespace: openshift-sriov-network-operator
spec:
 deviceType: netdevice
 isRdma: false
 needVhostNet: true
 nicSelector:
   vendor: "15b3"
      1 
      
   deviceID: "101b"
      2 
      
   rootDevices: ["00:05.0"]
 numVfs: 10
 priority: 99
 resourceName: sriovnic
 nodeSelector:
    feature.node.kubernetes.io/network-sriov.capable: "true"
      Copy to Clipboard
      Note

      The SR-IOV network node policy configuration example, with the setting deviceType: netdevice, is tailored specifically for Mellanox Network Interface Cards (NICs).

      1
      The vendor hexadecimal code of the SR-IOV network device. The value 15b3 is associated with a Mellanox NIC.
      2
      The device hexadecimal code of the SR-IOV network device.

    2. Apply the YAML by running the following command: 

      $ oc apply -f sriov-node-network-policy.yaml
      Copy to Clipboard
      Note

      Applying this might take some time due to the node requiring a reboot.

  3. Create an SR-IOV network:

    1. Create the SriovNetwork custom resource (CR) for the additional secondary SR-IOV network attachment as in the following example CR. Save the YAML as the file sriov-network-attachment.yaml: 

      apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
 name: sriov-network
 namespace: openshift-sriov-network-operator
spec:
 networkNamespace: test-namespace
 resourceName: sriovnic
 spoofChk: "off"
 trust: "on"
      Copy to Clipboard

    2. Apply the YAML by running the following command: 

      $ oc apply -f sriov-network-attachment.yaml
      Copy to Clipboard

  4. Create the VLAN secondary network:

    1. Using the following YAML example, create a file named vlan100-additional-network-configuration.yaml: 

      apiVersion: k8s.cni.cncf.io/v1
kind: NetworkAttachmentDefinition
metadata:
  name: vlan-100
  namespace: test-namespace
spec:
  config: |
    {
      "cniVersion": "0.4.0",
      "name": "vlan-100",
      "plugins": [
        {
          "type": "vlan",
          "master": "ext0",
      1 
      
          "mtu": 1500,
          "vlanId": 100,
          "linkInContainer": true,
      2 
      
          "ipam": {"type": "whereabouts", "ipRanges": [{"range": "1.1.1.0/24"}]}
        }
      ]
    }
      Copy to Clipboard
      1
      The VLAN configuration needs to specify the master name. This can be configured in the pod networks annotation.
      2
      The linkInContainer parameter must be specified.

    2. Apply the YAML file by running the following command: 

      $ oc apply -f vlan100-additional-network-configuration.yaml
      Copy to Clipboard

  5. Create a pod definition by using the earlier specified networks:

    1. Using the following YAML example, create a file named pod-a.yaml file:

      Note

      The manifest below includes 2 resources:

      • Namespace with security labels
      • Pod definition with appropriate network annotation 
      apiVersion: v1
kind: Namespace
metadata:
  name: test-namespace
  labels:
    pod-security.kubernetes.io/enforce: privileged
    pod-security.kubernetes.io/audit: privileged
    pod-security.kubernetes.io/warn: privileged
    security.openshift.io/scc.podSecurityLabelSync: "false"
---
apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  namespace: test-namespace
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
      {
        "name": "sriov-network",
        "namespace": "test-namespace",
        "interface": "ext0"
      1 
      
      },
      {
        "name": "vlan-100",
        "namespace": "test-namespace",
        "interface": "ext0.100"
      }
    ]'
spec:
  securityContext:
    runAsNonRoot: true
  containers:
    - name: nginx-container
      image: nginxinc/nginx-unprivileged:latest
      securityContext:
        allowPrivilegeEscalation: false
        capabilities:
          drop: ["ALL"]
      ports:
        - containerPort: 80
      seccompProfile:
        type: "RuntimeDefault"
      Copy to Clipboard
      1
      The name to be used as the master for the VLAN interface.

    2. Apply the YAML file by running the following command: 

      $ oc apply -f pod-a.yaml
      Copy to Clipboard

  6. Get detailed information about the nginx-pod within the test-namespace by running the following command: 

    $ oc describe pods nginx-pod -n test-namespace
    Copy to Clipboard

    Example output

    Name:         nginx-pod
Namespace:    test-namespace
Priority:     0
Node:         worker-1/10.46.186.105
Start Time:   Mon, 14 Aug 2023 16:23:13 -0400
Labels:       <none>
Annotations:  k8s.ovn.org/pod-networks:
                {"default":{"ip_addresses":["10.131.0.26/23"],"mac_address":"0a:58:0a:83:00:1a","gateway_ips":["10.131.0.1"],"routes":[{"dest":"10.128.0.0...
              k8s.v1.cni.cncf.io/network-status:
                [{
                    "name": "ovn-kubernetes",
                    "interface": "eth0",
                    "ips": [
                        "10.131.0.26"
                    ],
                    "mac": "0a:58:0a:83:00:1a",
                    "default": true,
                    "dns": {}
                },{
                    "name": "test-namespace/sriov-network",
                    "interface": "ext0",
                    "mac": "6e:a7:5e:3f:49:1b",
                    "dns": {},
                    "device-info": {
                        "type": "pci",
                        "version": "1.0.0",
                        "pci": {
                            "pci-address": "0000:d8:00.2"
                        }
                    }
                },{
                    "name": "test-namespace/vlan-100",
                    "interface": "ext0.100",
                    "ips": [
                        "1.1.1.1"
                    ],
                    "mac": "6e:a7:5e:3f:49:1b",
                    "dns": {}
                }]
              k8s.v1.cni.cncf.io/networks:
                [ { "name": "sriov-network", "namespace": "test-namespace", "interface": "ext0" }, { "name": "vlan-100", "namespace": "test-namespace", "i...
              openshift.io/scc: privileged
Status:       Running
IP:           10.131.0.26
IPs:
  IP:  10.131.0.26
    Copy to Clipboard

3.8.1.2. Creating a subinterface based on a bridge master interface in a container namespace

You can create a subinterface based on a bridge master interface that exists in a container namespace. Creating a subinterface can be applied to other types of interfaces.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You are logged in to the OpenShift Container Platform cluster as a user with cluster-admin privileges.

Procedure

  1. Create a dedicated container namespace where you want to deploy your pod by entering the following command: 

    $ oc new-project test-namespace
    Copy to Clipboard

  2. Using the following YAML example, create a bridge NetworkAttachmentDefinition custom resource definition (CRD) file named bridge-nad.yaml: 

    apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: bridge-network
spec:
  config: '{
    "cniVersion": "0.4.0",
    "name": "bridge-network",
    "type": "bridge",
    "bridge": "br-001",
    "isGateway": true,
    "ipMasq": true,
    "hairpinMode": true,
    "ipam": {
      "type": "host-local",
      "subnet": "10.0.0.0/24",
      "routes": [{"dst": "0.0.0.0/0"}]
    }
  }'
    Copy to Clipboard

  3. Run the following command to apply the NetworkAttachmentDefinition CRD to your OpenShift Container Platform cluster: 

    $ oc apply -f bridge-nad.yaml
    Copy to Clipboard

  4. Verify that you successfully created a NetworkAttachmentDefinition CRD by entering the following command: 

    $ oc get network-attachment-definitions
    Copy to Clipboard

    Example output

    NAME             AGE
bridge-network   15s
    Copy to Clipboard

  5. Using the following YAML example, create a file named ipvlan-additional-network-configuration.yaml for the IPVLAN secondary network configuration: 

    apiVersion: k8s.cni.cncf.io/v1
kind: NetworkAttachmentDefinition
metadata:
  name: ipvlan-net
  namespace: test-namespace
spec:
  config: '{
    "cniVersion": "0.3.1",
    "name": "ipvlan-net",
    "type": "ipvlan",
    "master": "net1",
    1 
    
    "mode": "l3",
    "linkInContainer": true,
    2 
    
    "ipam": {"type": "whereabouts", "ipRanges": [{"range": "10.0.0.0/24"}]}
  }'
    Copy to Clipboard
    1
    Specifies the ethernet interface to associate with the network attachment. This is subsequently configured in the pod networks annotation.
    2
    Specifies that the master interface is in the container network namespace.

  6. Apply the YAML file by running the following command: 

    $ oc apply -f ipvlan-additional-network-configuration.yaml
    Copy to Clipboard

  7. Verify that the NetworkAttachmentDefinition CRD has been created successfully by running the following command: 

    $ oc get network-attachment-definitions
    Copy to Clipboard

    Example output

    NAME             AGE
bridge-network   87s
ipvlan-net       9s
    Copy to Clipboard

  8. Using the following YAML example, create a file named pod-a.yaml for the pod definition: 

    apiVersion: v1
kind: Pod
metadata:
  name: pod-a
  namespace: test-namespace
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
      {
        "name": "bridge-network",
        "interface": "net1"
    1 
    
      },
      {
        "name": "ipvlan-net",
        "interface": "net2"
      }
    ]'
spec:
  securityContext:
    runAsNonRoot: true
    seccompProfile:
      type: RuntimeDefault
  containers:
  - name: test-pod
    image: quay.io/openshifttest/hello-sdn@sha256:c89445416459e7adea9a5a416b3365ed3d74f2491beb904d61dc8d1eb89a72a4
    securityContext:
      allowPrivilegeEscalation: false
      capabilities:
        drop: [ALL]
    Copy to Clipboard
    1
    Specifies the name to be used as the master for the IPVLAN interface.

  9. Apply the YAML file by running the following command: 

    $ oc apply -f pod-a.yaml
    Copy to Clipboard

  10. Verify that the pod is running by using the following command: 

    $ oc get pod -n test-namespace
    Copy to Clipboard

    Example output

    NAME    READY   STATUS    RESTARTS   AGE
pod-a   1/1     Running   0          2m36s
    Copy to Clipboard

  11. Show network interface information about the pod-a resource within the test-namespace by running the following command: 

    $ oc exec -n test-namespace pod-a -- ip a
    Copy to Clipboard

    Example output

    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: eth0@if105: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1400 qdisc noqueue state UP group default
    link/ether 0a:58:0a:d9:00:5d brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.217.0.93/23 brd 10.217.1.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::488b:91ff:fe84:a94b/64 scope link
       valid_lft forever preferred_lft forever
4: net1@if107: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether be:da:bd:7e:f4:37 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.0.0.2/24 brd 10.0.0.255 scope global net1
       valid_lft forever preferred_lft forever
    inet6 fe80::bcda:bdff:fe7e:f437/64 scope link
       valid_lft forever preferred_lft forever
5: net2@net1: <BROADCAST,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
    link/ether be:da:bd:7e:f4:37 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.1/24 brd 10.0.0.255 scope global net2
       valid_lft forever preferred_lft forever
    inet6 fe80::beda:bd00:17e:f437/64 scope link
       valid_lft forever preferred_lft forever
    Copy to Clipboard

    This output shows that the network interface net2 is associated with the physical interface net1.

3.9. Removing an additional network

As a cluster administrator you can remove an additional network attachment.

3.9.1. Removing a secondary network attachment definition

As a cluster administrator, you can remove a secondary network from your OpenShift Container Platform cluster. The secondary network is not removed from any pods it is attached to.

Prerequisites

  • Install the OpenShift CLI (oc).
  • Log in as a user with cluster-admin privileges.

Procedure

To remove a secondary network from your cluster, complete the following steps:

  1. Edit the Cluster Network Operator (CNO) in your default text editor by running the following command: 

    $ oc edit networks.operator.openshift.io cluster
    Copy to Clipboard

  2. Modify the CR by removing the configuration that the CNO created from the additionalNetworks collection for the secondary network that you want to remove. 

    apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  additionalNetworks: []
    1
    Copy to Clipboard
    1
    If you are removing the configuration mapping for the only secondary network attachment definition in the additionalNetworks collection, you must specify an empty collection.

  3. To remove a network attachment definition from the network of your cluster, enter the following command: 

    $ oc delete net-attach-def <name_of_NAD>
    1
    Copy to Clipboard
    1
    Replace <name_of_NAD> with the name of your network attachment definition.
  4. Save your changes and quit the text editor to commit your changes.

  5. Optional: Confirm that the secondary network CR was deleted by running the following command: 

    $ oc get network-attachment-definition --all-namespaces
    Copy to Clipboard
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