Dieser Inhalt ist in der von Ihnen ausgewählten Sprache nicht verfügbar.

Chapter 27. Configuring ingress cluster traffic


27.1. Configuring ingress cluster traffic overview

OpenShift Container Platform provides the following methods for communicating from outside the cluster with services running in the cluster.

The methods are recommended, in order or preference:

  • If you have HTTP/HTTPS, use an Ingress Controller.
  • If you have a TLS-encrypted protocol other than HTTPS. For example, for TLS with the SNI header, use an Ingress Controller.
  • Otherwise, use a Load Balancer, an External IP, or a
    NodePort
    .
Expand
MethodPurpose

Use an Ingress Controller

Allows access to HTTP/HTTPS traffic and TLS-encrypted protocols other than HTTPS (for example, TLS with the SNI header).

Automatically assign an external IP using a load balancer service

Allows traffic to non-standard ports through an IP address assigned from a pool. Most cloud platforms offer a method to start a service with a load-balancer IP address.

About MetalLB and the MetalLB Operator

Allows traffic to a specific IP address or address from a pool on the machine network. For bare-metal installations or platforms that are like bare metal, MetalLB provides a way to start a service with a load-balancer IP address.

Manually assign an external IP to a service

Allows traffic to non-standard ports through a specific IP address.

Configure a NodePort

Expose a service on all nodes in the cluster.

27.1.1. Comparision: Fault tolerant access to external IP addresses

For the communication methods that provide access to an external IP address, fault tolerant access to the IP address is another consideration. The following features provide fault tolerant access to an external IP address.

IP failover
IP failover manages a pool of virtual IP address for a set of nodes. It is implemented with Keepalived and Virtual Router Redundancy Protocol (VRRP). IP failover is a layer 2 mechanism only and relies on multicast. Multicast can have disadvantages for some networks.
MetalLB
MetalLB has a layer 2 mode, but it does not use multicast. Layer 2 mode has a disadvantage that it transfers all traffic for an external IP address through one node.
Manually assigning external IP addresses
You can configure your cluster with an IP address block that is used to assign external IP addresses to services. By default, this feature is disabled. This feature is flexible, but places the largest burden on the cluster or network administrator. The cluster is prepared to receive traffic that is destined for the external IP, but each customer has to decide how they want to route traffic to nodes.

27.2. Configuring ExternalIPs for services

As a cluster administrator, you can select an IP address block that is external to the cluster that can send traffic to services in the cluster.

This functionality is generally most useful for clusters installed on bare-metal hardware.

27.2.1. Prerequisites

  • Your network infrastructure must route traffic for the external IP addresses to your cluster.

27.2.2. About ExternalIP

For non-cloud environments, OpenShift Container Platform supports the use of the ExternalIP facility to specify external IP addresses in the

spec.externalIPs[]
parameter of the
Service
object. A service configured with an ExternalIP functions similarly to a service with
type=NodePort
, whereby you traffic directs to a local node for load balancing.

Important

For cloud environments, use the load balancer services for automatic deployment of a cloud load balancer to target the endpoints of a service.

After you specify a value for the parameter, OpenShift Container Platform assigns an additional virtual IP address to the service. The IP address can exist outside of the service network that you defined for your cluster.

Warning

Because ExternalIP is disabled by default, enabling the ExternalIP functionality might introduce security risks for the service, because in-cluster traffic to an external IP address is directed to that service. This configuration means that cluster users could intercept sensitive traffic destined for external resources.

You can use either a MetalLB implementation or an IP failover deployment to attach an ExternalIP resource to a service in the following ways:

Automatic assignment of an external IP
OpenShift Container Platform automatically assigns an IP address from the autoAssignCIDRs CIDR block to the spec.externalIPs[] array when you create a Service object with spec.type=LoadBalancer set. For this configuration, OpenShift Container Platform implements a cloud version of the load balancer service type and assigns IP addresses to the services. Automatic assignment is disabled by default and must be configured by a cluster administrator as described in the "Configuration for ExternalIP" section.
Manual assignment of an external IP
OpenShift Container Platform uses the IP addresses assigned to the spec.externalIPs[] array when you create a Service object. You cannot specify an IP address that is already in use by another service.

After using either the MetalLB implementation or an IP failover deployment to host external IP address blocks, you must configure your networking infrastructure to ensure that the external IP address blocks are routed to your cluster. This configuration means that the IP address is not configured in the network interfaces from nodes. To handle the traffic, you must configure the routing and access to the external IP by using a method, such as static Address Resolution Protocol (ARP) entries.

OpenShift Container Platform extends the ExternalIP functionality in Kubernetes by adding the following capabilities:

  • Restrictions on the use of external IP addresses by users through a configurable policy
  • Allocation of an external IP address automatically to a service upon request

27.2.3. Configuration for ExternalIP

The following parameters in the

Network.config.openshift.io
custom resource (CR) govern the use of an external IP address in OpenShift Container Platform:

  • spec.externalIP.autoAssignCIDRs
    defines an IP address block used by the load balancer when choosing an external IP address for the service. OpenShift Container Platform supports only a single IP address block for automatic assignment. This configuration requires less steps than manually assigning ExternalIPs to services, which requires managing the port space of a limited number of shared IP addresses. If you enable automatic assignment, the Cloud Controller Manager Operator allocates an external IP address to a
    Service
    object with
    spec.type=LoadBalancer
    defind in its configuration.
  • spec.externalIP.policy
    defines the permissible IP address blocks when manually specifying an IP address. OpenShift Container Platform does not apply policy rules to IP address blocks that you defined in the
    spec.externalIP.autoAssignCIDRs
    parameter.

If routed correctly, external traffic from the configured external IP address block can reach service endpoints through any TCP or UDP port that the service exposes.

Important

As a cluster administrator, you must configure routing to externalIPs. You must also ensure that the IP address block you assign terminates at one or more nodes in your cluster. For more information, see Kubernetes External IPs.

OpenShift Container Platform supports both automatic and manual IP address assignment. This support guarantees that each address gets assigned to a maximum of one service and that each service can expose its chosen ports regardless of the ports exposed by other services.

Note

To use IP address blocks defined by

autoAssignCIDRs
in OpenShift Container Platform, you must configure the necessary IP address assignment and routing for your host network.

The following YAML shows a

Service
object with a configured external IP:

apiVersion: v1
kind: Service
metadata:
  name: http-service
spec:
  clusterIP: 172.30.163.110
  externalIPs:
  - 192.168.132.253
  externalTrafficPolicy: Cluster
  ports:
  - name: highport
    nodePort: 31903
    port: 30102
    protocol: TCP
    targetPort: 30102
  selector:
    app: web
  sessionAffinity: None
  type: LoadBalancer
status:
  loadBalancer:
    ingress:
    - ip: 192.168.132.253
# ...

If you run a private cluster on a cloud-provider platform, you can change the publishing scope to

internal
for the load balancer of the Ingress Controller by running the following
patch
command:

$ oc -n openshift-ingress-operator patch ingresscontrollers/ingress-controller-with-nlb --type=merge --patch='{"spec":{"endpointPublishingStrategy":{"loadBalancer":{"scope":"Internal"}}}}'

After you run this command, the Ingress Controller restricts access to routes for OpenShift Container Platform applications to internal networks only.

27.2.4. Restrictions on the assignment of an external IP address

As a cluster administrator, you can specify IP address blocks to allow and to reject IP addresses for a service. Restrictions apply only to users without

cluster-admin
privileges. A cluster administrator can always set the service
spec.externalIPs[]
field to any IP address.

You configure an IP address policy by specifying Classless Inter-Domain Routing (CIDR) address blocks for the

spec.ExternalIP.policy
parameter in the
policy
object.

Example in JSON form of a policy object and its CIDR parameters

{
  "policy": {
    "allowedCIDRs": [],
    "rejectedCIDRs": []
  }
}

When configuring policy restrictions, the following rules apply:

  • If
    policy
    is set to
    {}
    , creating a
    Service
    object with
    spec.ExternalIPs[]
    results in a failed service. This setting is the default for OpenShift Container Platform. The same behavior exists for
    policy: null
    .
  • If

    policy
    is set and either
    policy.allowedCIDRs[]
    or
    policy.rejectedCIDRs[]
    is set, the following rules apply:

    • If
      allowedCIDRs[]
      and
      rejectedCIDRs[]
      are both set,
      rejectedCIDRs[]
      has precedence over
      allowedCIDRs[]
      .
    • If
      allowedCIDRs[]
      is set, creating a
      Service
      object with
      spec.ExternalIPs[]
      succeeds only if the specified IP addresses are allowed.
    • If
      rejectedCIDRs[]
      is set, creating a
      Service
      object with
      spec.ExternalIPs[]
      succeeds only if the specified IP addresses are not rejected.

27.2.5. Example policy objects

The examples in this section show different

spec.externalIP.policy
configurations.

  • In the following example, the policy prevents OpenShift Container Platform from creating any service with a specified external IP address.

    Example policy to reject any value specified for Service object spec.externalIPs[]

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      externalIP:
        policy: {}
    # ...

  • In the following example, both the

    allowedCIDRs
    and
    rejectedCIDRs
    fields are set.

    Example policy that includes both allowed and rejected CIDR blocks

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      externalIP:
        policy:
          allowedCIDRs:
          - 172.16.66.10/23
          rejectedCIDRs:
          - 172.16.66.10/24
    # ...

  • In the following example,

    policy
    is set to
    {}
    . With this configuration, using the
    oc get networks.config.openshift.io -o yaml
    command to view the configuration means
    policy
    parameter does not show on the command output. The same behavior exists for
    policy: null
    .

    Example policy to allow any value specified for Service object spec.externalIPs[]

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      clusterNetwork:
      - cidr: 10.128.0.0/14
        hostPrefix: 23
      externalIP:
        policy: {}
    # ...

27.2.6. ExternalIP address block configuration

The configuration for ExternalIP address blocks is defined by a Network custom resource (CR) named

cluster
. The Network CR is part of the
config.openshift.io
API group.

Important

During cluster installation, the Cluster Version Operator (CVO) automatically creates a Network CR named

cluster
. Creating any other CR objects of this type is not supported.

The following YAML describes the ExternalIP configuration:

Network.config.openshift.io CR named cluster

apiVersion: config.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  externalIP:
    autoAssignCIDRs: [] 
1

    policy: 
2

      ...

1
Defines the IP address block in CIDR format that is available for automatic assignment of external IP addresses to a service. Only a single IP address range is allowed.
2
Defines restrictions on manual assignment of an IP address to a service. If no restrictions are defined, specifying the spec.externalIP field in a Service object is not allowed. By default, no restrictions are defined.

The following YAML describes the fields for the

policy
stanza:

Network.config.openshift.io policy stanza

policy:
  allowedCIDRs: [] 
1

  rejectedCIDRs: [] 
2

1
A list of allowed IP address ranges in CIDR format.
2
A list of rejected IP address ranges in CIDR format.

27.2.6.1. Example external IP configurations

Several possible configurations for external IP address pools are displayed in the following examples:

  • The following YAML describes a configuration that enables automatically assigned external IP addresses:

    Example configuration with spec.externalIP.autoAssignCIDRs set

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      ...
      externalIP:
        autoAssignCIDRs:
        - 192.168.132.254/29

  • The following YAML configures policy rules for the allowed and rejected CIDR ranges:

    Example configuration with spec.externalIP.policy set

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      ...
      externalIP:
        policy:
          allowedCIDRs:
          - 192.168.132.0/29
          - 192.168.132.8/29
          rejectedCIDRs:
          - 192.168.132.7/32

27.2.7. Configure external IP address blocks for your cluster

As a cluster administrator, you can configure the following ExternalIP settings:

  • An ExternalIP address block used by OpenShift Container Platform to automatically populate the
    spec.clusterIP
    field for a
    Service
    object.
  • A policy object to restrict what IP addresses may be manually assigned to the
    spec.clusterIP
    array of a
    Service
    object.

Prerequisites

  • Install the OpenShift CLI (
    oc
    ).
  • Access to the cluster as a user with the
    cluster-admin
    role.

Procedure

  1. Optional: To display the current external IP configuration, enter the following command:

    $ oc describe networks.config cluster
  2. To edit the configuration, enter the following command:

    $ oc edit networks.config cluster
  3. Modify the ExternalIP configuration, as in the following example:

    apiVersion: config.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec:
      ...
      externalIP: 
    1
    
      ...
    1
    Specify the configuration for the externalIP stanza.
  4. To confirm the updated ExternalIP configuration, enter the following command:

    $ oc get networks.config cluster -o go-template='{{.spec.externalIP}}{{"\n"}}'

27.2.9. Next steps

27.3. Configuring ingress cluster traffic using an Ingress Controller

OpenShift Container Platform provides methods for communicating from outside the cluster with services running in the cluster. This method uses an Ingress Controller.

27.3.1. Using Ingress Controllers and routes

The Ingress Operator manages Ingress Controllers and wildcard DNS.

Using an Ingress Controller is the most common way to allow external access to an OpenShift Container Platform cluster.

An Ingress Controller is configured to accept external requests and proxy them based on the configured routes. This is limited to HTTP, HTTPS using SNI, and TLS using SNI, which is sufficient for web applications and services that work over TLS with SNI.

Work with your administrator to configure an Ingress Controller to accept external requests and proxy them based on the configured routes.

The administrator can create a wildcard DNS entry and then set up an Ingress Controller. Then, you can work with the edge Ingress Controller without having to contact the administrators.

By default, every Ingress Controller in the cluster can admit any route created in any project in the cluster.

The Ingress Controller:

  • Has two replicas by default, which means it should be running on two worker nodes.
  • Can be scaled up to have more replicas on more nodes.
Note

The procedures in this section require prerequisites performed by the cluster administrator.

27.3.2. Prerequisites

Before starting the following procedures, the administrator must:

  • Set up the external port to the cluster networking environment so that requests can reach the cluster.
  • Make sure there is at least one user with cluster admin role. To add this role to a user, run the following command:

    $ oc adm policy add-cluster-role-to-user cluster-admin username
  • You have an OpenShift Container Platform cluster with at least one master and at least one node and a system outside the cluster that has network access to the cluster. This procedure assumes that the external system is on the same subnet as the cluster. The additional networking required for external systems on a different subnet is out-of-scope for this topic.

27.3.3. Creating a project and service

If the project and service that you want to expose does not exist, create the project and then create the service.

If the project and service already exists, skip to the procedure on exposing the service to create a route.

Prerequisites

  • Install the OpenShift CLI (
    oc
    ) and log in as a cluster administrator.

Procedure

  1. Create a new project for your service by running the

    oc new-project
    command:

    $ oc new-project <project_name>
  2. Use the

    oc new-app
    command to create your service:

    $ oc new-app nodejs:12~https://github.com/sclorg/nodejs-ex.git
  3. To verify that the service was created, run the following command:

    $ oc get svc -n <project_name>

    Example output

    NAME        TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    nodejs-ex   ClusterIP   172.30.197.157   <none>        8080/TCP   70s

    Note

    By default, the new service does not have an external IP address.

27.3.4. Exposing the service by creating a route

You can expose the service as a route by using the

oc expose
command.

Prerequisites

  • You logged into OpenShift Container Platform.

Procedure

  1. Log in to the project where the service you want to expose is located:

    $ oc project <project_name>
  2. Run the

    oc expose service
    command to expose the route:

    $ oc expose service nodejs-ex

    Example output

    route.route.openshift.io/nodejs-ex exposed

  3. To verify that the service is exposed, you can use a tool, such as

    curl
    to check that the service is accessible from outside the cluster.

    1. To find the hostname of the route, enter the following command:

      $ oc get route

      Example output

      NAME        HOST/PORT                        PATH   SERVICES    PORT       TERMINATION   WILDCARD
      nodejs-ex   nodejs-ex-myproject.example.com         nodejs-ex   8080-tcp                 None

    2. To check that the host responds to a GET request, enter the following command:

      Example curl command

      $ curl --head nodejs-ex-myproject.example.com

      Example output

      HTTP/1.1 200 OK
      ...

27.3.5. Ingress sharding in OpenShift Container Platform

In OpenShift Container Platform, an Ingress Controller can serve all routes, or it can serve a subset of routes. By default, the Ingress Controller serves any route created in any namespace in the cluster. You can add additional Ingress Controllers to your cluster to optimize routing by creating shards, which are subsets of routes based on selected characteristics. To mark a route as a member of a shard, use labels in the route or namespace

metadata
field. The Ingress Controller uses selectors, also known as a selection expression, to select a subset of routes from the entire pool of routes to serve.

Ingress sharding is useful in cases where you want to load balance incoming traffic across multiple Ingress Controllers, when you want to isolate traffic to be routed to a specific Ingress Controller, or for a variety of other reasons described in the next section.

By default, each route uses the default domain of the cluster. However, routes can be configured to use the domain of the router instead.

27.3.6. Ingress Controller sharding

You can use Ingress sharding, also known as router sharding, to distribute a set of routes across multiple routers by adding labels to routes, namespaces, or both. The Ingress Controller uses a corresponding set of selectors to admit only the routes that have a specified label. Each Ingress shard comprises the routes that are filtered by using a given selection expression.

As the primary mechanism for traffic to enter the cluster, the demands on the Ingress Controller can be significant. As a cluster administrator, you can shard the routes to:

  • Balance Ingress Controllers, or routers, with several routes to accelerate responses to changes.
  • Assign certain routes to have different reliability guarantees than other routes.
  • Allow certain Ingress Controllers to have different policies defined.
  • Allow only specific routes to use additional features.
  • Expose different routes on different addresses so that internal and external users can see different routes, for example.
  • Transfer traffic from one version of an application to another during a blue-green deployment.

When Ingress Controllers are sharded, a given route is admitted to zero or more Ingress Controllers in the group. The status of a route describes whether an Ingress Controller has admitted the route. An Ingress Controller only admits a route if the route is unique to a shard.

With sharding, you can distribute subsets of routes over multiple Ingress Controllers. These subsets can be nonoverlapping, also called traditional sharding, or overlapping, otherwise known as overlapped sharding.

The following table outlines three sharding methods:

Expand
Sharding methodDescription

Namespace selector

After you add a namespace selector to the Ingress Controller, all routes in a namespace that have matching labels for the namespace selector are included in the Ingress shard. Consider this method when an Ingress Controller serves all routes created in a namespace.

Route selector

After you add a route selector to the Ingress Controller, all routes with labels that match the route selector are included in the Ingress shard. Consider this method when you want an Ingress Controller to serve only a subset of routes or a specific route in a namespace.

Namespace and route selectors

Provides your Ingress Controller scope for both namespace selector and route selector methods. Consider this method when you want the flexibility of both the namespace selector and the route selector methods.

27.3.6.1. Traditional sharding example

An example of a configured Ingress Controller

finops-router
that has the label selector
spec.namespaceSelector.matchExpressions
with key values set to
finance
and
ops
:

Example YAML definition for finops-router

apiVersion: operator.openshift.io/v1
kind: IngressController
metadata:
  name: finops-router
  namespace: openshift-ingress-operator
spec:
  namespaceSelector:
    matchExpressions:
    - key: name
      operator: In
      values:
      - finance
      - ops

An example of a configured Ingress Controller

dev-router
that has the label selector
spec.namespaceSelector.matchLabels.name
with the key value set to
dev
:

Example YAML definition for dev-router

apiVersion: operator.openshift.io/v1
kind: IngressController
metadata:
  name: dev-router
  namespace: openshift-ingress-operator
spec:
  namespaceSelector:
    matchLabels:
      name: dev

If all application routes are in separate namespaces, such as each labeled with

name:finance
,
name:ops
, and
name:dev
, the configuration effectively distributes your routes between the two Ingress Controllers. OpenShift Container Platform routes for console, authentication, and other purposes should not be handled.

In the previous scenario, sharding becomes a special case of partitioning, with no overlapping subsets. Routes are divided between router shards.

Warning

The

default
Ingress Controller continues to serve all routes unless the
namespaceSelector
or
routeSelector
fields contain routes that are meant for exclusion. See this Red Hat Knowledgebase solution and the section "Sharding the default Ingress Controller" for more information on how to exclude routes from the default Ingress Controller.

27.3.6.2. Overlapped sharding example

An example of a configured Ingress Controller

devops-router
that has the label selector
spec.namespaceSelector.matchExpressions
with key values set to
dev
and
ops
:

Example YAML definition for devops-router

apiVersion: operator.openshift.io/v1
kind: IngressController
metadata:
  name: devops-router
  namespace: openshift-ingress-operator
spec:
  namespaceSelector:
    matchExpressions:
    - key: name
      operator: In
      values:
      - dev
      - ops

The routes in the namespaces labeled

name:dev
and
name:ops
are now serviced by two different Ingress Controllers. With this configuration, you have overlapping subsets of routes.

With overlapping subsets of routes you can create more complex routing rules. For example, you can divert higher priority traffic to the dedicated

finops-router
while sending lower priority traffic to
devops-router
.

27.3.6.3. Sharding the default Ingress Controller

After creating a new Ingress shard, there might be routes that are admitted to your new Ingress shard that are also admitted by the default Ingress Controller. This is because the default Ingress Controller has no selectors and admits all routes by default.

You can restrict an Ingress Controller from servicing routes with specific labels using either namespace selectors or route selectors. The following procedure restricts the default Ingress Controller from servicing your newly sharded

finance
,
ops
, and
dev
, routes using a namespace selector. This adds further isolation to Ingress shards.

Important

You must keep all of OpenShift Container Platform’s administration routes on the same Ingress Controller. Therefore, avoid adding additional selectors to the default Ingress Controller that exclude these essential routes.

Prerequisites

  • You installed the OpenShift CLI (
    oc
    ).
  • You are logged in as a project administrator.

Procedure

  1. Modify the default Ingress Controller by running the following command:

    $ oc edit ingresscontroller -n openshift-ingress-operator default
  2. Edit the Ingress Controller to contain a

    namespaceSelector
    that excludes the routes with any of the
    finance
    ,
    ops
    , and
    dev
    labels:

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      name: default
      namespace: openshift-ingress-operator
    spec:
      namespaceSelector:
        matchExpressions:
          - key: name
            operator: NotIn
            values:
              - finance
              - ops
              - dev

The default Ingress Controller will no longer serve the namespaces labeled

name:finance
,
name:ops
, and
name:dev
.

27.3.6.4. Ingress sharding and DNS

The cluster administrator is responsible for making a separate DNS entry for each router in a project. A router will not forward unknown routes to another router.

Consider the following example:

  • Router A lives on host 192.168.0.5 and has routes with
    *.foo.com
    .
  • Router B lives on host 192.168.1.9 and has routes with
    *.example.com
    .

Separate DNS entries must resolve

*.foo.com
to the node hosting Router A and
*.example.com
to the node hosting Router B:

  • *.foo.com A IN 192.168.0.5
  • *.example.com A IN 192.168.1.9

27.3.6.5. Configuring Ingress Controller sharding by using route labels

Ingress Controller sharding by using route labels means that the Ingress Controller serves any route in any namespace that is selected by the route selector.

Figure 27.1. Ingress sharding using route labels

A diagram showing multiple Ingress Controllers with different route selectors serving any route containing a label that matches a given route selector regardless of the namespace a route belongs to

Ingress Controller sharding is useful when balancing incoming traffic load among a set of Ingress Controllers and when isolating traffic to a specific Ingress Controller. For example, company A goes to one Ingress Controller and company B to another.

Procedure

  1. Edit the

    router-internal.yaml
    file:

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      name: sharded
      namespace: openshift-ingress-operator
    spec:
      domain: <apps-sharded.basedomain.example.net> 
    1
    
      nodePlacement:
        nodeSelector:
          matchLabels:
            node-role.kubernetes.io/worker: ""
      routeSelector:
        matchLabels:
          type: sharded
    1
    Specify a domain to be used by the Ingress Controller. This domain must be different from the default Ingress Controller domain.
  2. Apply the Ingress Controller

    router-internal.yaml
    file:

    # oc apply -f router-internal.yaml

    The Ingress Controller selects routes in any namespace that have the label

    type: sharded
    .

  3. Create a new route using the domain configured in the

    router-internal.yaml
    :

    $ oc expose svc <service-name> --hostname <route-name>.apps-sharded.basedomain.example.net

Ingress Controller sharding by using namespace labels means that the Ingress Controller serves any route in any namespace that is selected by the namespace selector.

Figure 27.2. Ingress sharding using namespace labels

A diagram showing multiple Ingress Controllers with different namespace selectors serving routes that belong to the namespace containing a label that matches a given namespace selector

Ingress Controller sharding is useful when balancing incoming traffic load among a set of Ingress Controllers and when isolating traffic to a specific Ingress Controller. For example, company A goes to one Ingress Controller and company B to another.

Procedure

  1. Edit the

    router-internal.yaml
    file:

    $ cat router-internal.yaml

    Example output

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      name: sharded
      namespace: openshift-ingress-operator
    spec:
      domain: <apps-sharded.basedomain.example.net> 
    1
    
      nodePlacement:
        nodeSelector:
          matchLabels:
            node-role.kubernetes.io/worker: ""
      namespaceSelector:
        matchLabels:
          type: sharded

    1
    Specify a domain to be used by the Ingress Controller. This domain must be different from the default Ingress Controller domain.
  2. Apply the Ingress Controller

    router-internal.yaml
    file:

    $ oc apply -f router-internal.yaml

    The Ingress Controller selects routes in any namespace that is selected by the namespace selector that have the label

    type: sharded
    .

  3. Create a new route using the domain configured in the

    router-internal.yaml
    :

    $ oc expose svc <service-name> --hostname <route-name>.apps-sharded.basedomain.example.net

27.3.6.7. Creating a route for Ingress Controller sharding

A route allows you to host your application at a URL. In this case, the hostname is not set and the route uses a subdomain instead. When you specify a subdomain, you automatically use the domain of the Ingress Controller that exposes the route. For situations where a route is exposed by multiple Ingress Controllers, the route is hosted at multiple URLs.

The following procedure describes how to create a route for Ingress Controller sharding, using the

hello-openshift
application as an example.

Ingress Controller sharding is useful when balancing incoming traffic load among a set of Ingress Controllers and when isolating traffic to a specific Ingress Controller. For example, company A goes to one Ingress Controller and company B to another.

Prerequisites

  • You installed the OpenShift CLI (
    oc
    ).
  • You are logged in as a project administrator.
  • You have a web application that exposes a port and an HTTP or TLS endpoint listening for traffic on the port.
  • You have configured the Ingress Controller for sharding.

Procedure

  1. Create a project called

    hello-openshift
    by running the following command:

    $ oc new-project hello-openshift
  2. Create a pod in the project by running the following command:

    $ oc create -f https://raw.githubusercontent.com/openshift/origin/master/examples/hello-openshift/hello-pod.json
  3. Create a service called

    hello-openshift
    by running the following command:

    $ oc expose pod/hello-openshift
  4. Create a route definition called

    hello-openshift-route.yaml
    :

    YAML definition of the created route for sharding:

    apiVersion: route.openshift.io/v1
    kind: Route
    metadata:
      labels:
        type: sharded 
    1
    
      name: hello-openshift-edge
      namespace: hello-openshift
    spec:
      subdomain: hello-openshift 
    2
    
      tls:
        termination: edge
      to:
        kind: Service
        name: hello-openshift

    1
    Both the label key and its corresponding label value must match the ones specified in the Ingress Controller. In this example, the Ingress Controller has the label key and value type: sharded.
    2
    The route will be exposed using the value of the subdomain field. When you specify the subdomain field, you must leave the hostname unset. If you specify both the host and subdomain fields, then the route will use the value of the host field, and ignore the subdomain field.
  5. Use

    hello-openshift-route.yaml
    to create a route to the
    hello-openshift
    application by running the following command:

    $ oc -n hello-openshift create -f hello-openshift-route.yaml

Verification

  • Get the status of the route with the following command:

    $ oc -n hello-openshift get routes/hello-openshift-edge -o yaml

    The resulting

    Route
    resource should look similar to the following:

    Example output

    apiVersion: route.openshift.io/v1
    kind: Route
    metadata:
      labels:
        type: sharded
      name: hello-openshift-edge
      namespace: hello-openshift
    spec:
      subdomain: hello-openshift
      tls:
        termination: edge
      to:
        kind: Service
        name: hello-openshift
    status:
      ingress:
      - host: hello-openshift.<apps-sharded.basedomain.example.net> 
    1
    
        routerCanonicalHostname: router-sharded.<apps-sharded.basedomain.example.net> 
    2
    
        routerName: sharded 
    3

    1
    The hostname the Ingress Controller, or router, uses to expose the route. The value of the host field is automatically determined by the Ingress Controller, and uses its domain. In this example, the domain of the Ingress Controller is <apps-sharded.basedomain.example.net>.
    2
    The hostname of the Ingress Controller.
    3
    The name of the Ingress Controller. In this example, the Ingress Controller has the name sharded.

27.3.6.8. Additional resources

27.4. Configuring the Ingress Controller endpoint publishing strategy

The

endpointPublishingStrategy
is used to publish the Ingress Controller endpoints to other networks, enable load balancer integrations, and provide access to other systems.

Important

On Red Hat OpenStack Platform (RHOSP), the

LoadBalancerService
endpoint publishing strategy is supported only if a cloud provider is configured to create health monitors. For RHOSP 16.2, this strategy is possible only if you use the Amphora Octavia provider.

For more information, see the "Setting RHOSP Cloud Controller Manager options" section of the RHOSP installation documentation.

27.4.1. Ingress Controller endpoint publishing strategy

NodePortService endpoint publishing strategy

The

NodePortService
endpoint publishing strategy publishes the Ingress Controller using a Kubernetes NodePort service.

In this configuration, the Ingress Controller deployment uses container networking. A

NodePortService
is created to publish the deployment. The specific node ports are dynamically allocated by OpenShift Container Platform; however, to support static port allocations, your changes to the node port field of the managed
NodePortService
are preserved.

Figure 27.3. Diagram of NodePortService

OpenShift Container Platform Ingress NodePort endpoint publishing strategy

The preceding graphic shows the following concepts pertaining to OpenShift Container Platform Ingress NodePort endpoint publishing strategy:

  • All the available nodes in the cluster have their own, externally accessible IP addresses. The service running in the cluster is bound to the unique NodePort for all the nodes.
  • When the client connects to a node that is down, for example, by connecting the
    10.0.128.4
    IP address in the graphic, the node port directly connects the client to an available node that is running the service. In this scenario, no load balancing is required. As the image shows, the
    10.0.128.4
    address is down and another IP address must be used instead.
Note

The Ingress Operator ignores any updates to

.spec.ports[].nodePort
fields of the service.

By default, ports are allocated automatically and you can access the port allocations for integrations. However, sometimes static port allocations are necessary to integrate with existing infrastructure which may not be easily reconfigured in response to dynamic ports. To achieve integrations with static node ports, you can update the managed service resource directly.

For more information, see the Kubernetes Services documentation on NodePort.

HostNetwork endpoint publishing strategy

The

HostNetwork
endpoint publishing strategy publishes the Ingress Controller on node ports where the Ingress Controller is deployed.

An Ingress Controller with the

HostNetwork
endpoint publishing strategy can have only one pod replica per node. If you want n replicas, you must use at least n nodes where those replicas can be scheduled. Because each pod replica requests ports
80
and
443
on the node host where it is scheduled, a replica cannot be scheduled to a node if another pod on the same node is using those ports.

The

HostNetwork
object has a
hostNetwork
field with the following default values for the optional binding ports:
httpPort: 80
,
httpsPort: 443
, and
statsPort: 1936
. By specifying different binding ports for your network, you can deploy multiple Ingress Controllers on the same node for the
HostNetwork
strategy.

Example

apiVersion: operator.openshift.io/v1
kind: IngressController
metadata:
  name: internal
  namespace: openshift-ingress-operator
spec:
  domain: example.com
  endpointPublishingStrategy:
    type: HostNetwork
    hostNetwork:
      httpPort: 80
      httpsPort: 443
      statsPort: 1936

When a cluster administrator installs a new cluster without specifying that the cluster is private, the default Ingress Controller is created with a

scope
set to
External
. Cluster administrators can change an
External
scoped Ingress Controller to
Internal
.

Prerequisites

  • You installed the
    oc
    CLI.

Procedure

  • To change an

    External
    scoped Ingress Controller to
    Internal
    , enter the following command:

    $ oc -n openshift-ingress-operator patch ingresscontrollers/default --type=merge --patch='{"spec":{"endpointPublishingStrategy":{"type":"LoadBalancerService","loadBalancer":{"scope":"Internal"}}}}'
  • To check the status of the Ingress Controller, enter the following command:

    $ oc -n openshift-ingress-operator get ingresscontrollers/default -o yaml
    • The

      Progressing
      status condition indicates whether you must take further action. For example, the status condition can indicate that you need to delete the service by entering the following command:

      $ oc -n openshift-ingress delete services/router-default

      If you delete the service, the Ingress Operator recreates it as

      Internal
      .

When a cluster administrator installs a new cluster without specifying that the cluster is private, the default Ingress Controller is created with a

scope
set to
External
.

The Ingress Controller’s scope can be configured to be

Internal
during installation or after, and cluster administrators can change an
Internal
Ingress Controller to
External
.

Important

On some platforms, it is necessary to delete and recreate the service.

Changing the scope can cause disruption to Ingress traffic, potentially for several minutes. This applies to platforms where it is necessary to delete and recreate the service, because the procedure can cause OpenShift Container Platform to deprovision the existing service load balancer, provision a new one, and update DNS.

Prerequisites

  • You installed the
    oc
    CLI.

Procedure

  • To change an

    Internal
    scoped Ingress Controller to
    External
    , enter the following command:

    $ oc -n openshift-ingress-operator patch ingresscontrollers/private --type=merge --patch='{"spec":{"endpointPublishingStrategy":{"type":"LoadBalancerService","loadBalancer":{"scope":"External"}}}}'
  • To check the status of the Ingress Controller, enter the following command:

    $ oc -n openshift-ingress-operator get ingresscontrollers/default -o yaml
    • The

      Progressing
      status condition indicates whether you must take further action. For example, the status condition can indicate that you need to delete the service by entering the following command:

      $ oc -n openshift-ingress delete services/router-default

      If you delete the service, the Ingress Operator recreates it as

      External
      .

27.4.1.3. Adding a single NodePort service to an Ingress Controller

Instead of creating a

NodePort
-type
Service
for each project, you can create a custom Ingress Controller to use the
NodePortService
endpoint publishing strategy. To prevent port conflicts, consider this configuration for your Ingress Controller when you want to apply a set of routes, through Ingress sharding, to nodes that might already have a
HostNetwork
Ingress Controller.

Before you set a

NodePort
-type
Service
for each project, read the following considerations:

  • You must create a wildcard DNS record for the Nodeport Ingress Controller domain. A Nodeport Ingress Controller route can be reached from the address of a worker node. For more information about the required DNS records for routes, see "User-provisioned DNS requirements".
  • You must expose a route for your service and specify the
    --hostname
    argument for your custom Ingress Controller domain.
  • You must append the port that is assigned to the
    NodePort
    -type
    Service
    in the route so that you can access application pods.

Prerequisites

  • You installed the OpenShift CLI (
    oc
    ).
  • Logged in as a user with
    cluster-admin
    privileges.
  • You created a wildcard DNS record.

Procedure

  1. Create a custom resource (CR) file for the Ingress Controller:

    Example of a CR file that defines information for the IngressController object

    apiVersion: v1
    items:
    - apiVersion: operator.openshift.io/v1
      kind: IngressController
      metadata:
        name: <custom_ic_name> 
    1
    
        namespace: openshift-ingress-operator
      spec:
        replicas: 1
        domain: <custom_ic_domain_name> 
    2
    
        nodePlacement:
          nodeSelector:
            matchLabels:
              <key>: <value> 
    3
    
        namespaceSelector:
         matchLabels:
           <key>: <value> 
    4
    
        endpointPublishingStrategy:
          type: NodePortService
    # ...

    1
    Specify the a custom name for the IngressController CR.
    2
    The DNS name that the Ingress Controller services. As an example, the default ingresscontroller domain is apps.ipi-cluster.example.com, so you would specify the <custom_ic_domain_name> as nodeportsvc.ipi-cluster.example.com.
    3
    Specify the label for the nodes that include the custom Ingress Controller.
    4
    Specify the label for a set of namespaces. Substitute <key>:<value> with a map of key-value pairs where <key> is a unique name for the new label and <value> is its value. For example: ingresscontroller: custom-ic.
  2. Add a label to a node by using the

    oc label node
    command:

    $ oc label node <node_name> <key>=<value> 
    1
    1
    Where <value> must match the key-value pair specified in the nodePlacement section of your IngressController CR.
  3. Create the

    IngressController
    object:

    $ oc create -f <ingress_controller_cr>.yaml
  4. Find the port for the service created for the

    IngressController
    CR:

    $ oc get svc -n openshift-ingress

    Example output that shows port 80:32432/TCP for the router-nodeport-custom-ic3 service

    NAME                        TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                                     AGE
    router-internal-default      ClusterIP   172.30.195.74    <none>        80/TCP,443/TCP,1936/TCP                     223d
    router-nodeport-custom-ic3   NodePort    172.30.109.219   <none>        80:32432/TCP,443:31366/TCP,1936:30499/TCP   155m

  5. To create a new project, enter the following command:

    $ oc new-project <project_name>
  6. To label the new namespace, enter the following command:

    $ oc label namespace <project_name> <key>=<value> 
    1
    1
    Where <key>=<value> must match the value in the namespaceSelector section of your Ingress Controller CR.
  7. Create a new application in your cluster:

    $ oc new-app --image=<image_name> 
    1
    1
    An example of <image_name> is quay.io/openshifttest/hello-openshift:multiarch.
  8. Create a

    Route
    object for a service, so that the pod can use the service to expose the application external to the cluster.

    $ oc expose svc/<service_name> --hostname=<svc_name>-<project_name>.<custom_ic_domain_name> 
    1
    Note

    You must specify the domain name of your custom Ingress Controller in the

    --hostname
    argument. If you do not do this, the Ingress Operator uses the default Ingress Controller to serve all the routes for your cluster.

  9. Check that the route has the

    Admitted
    status and that it includes metadata for the custom Ingress Controller:

    $ oc get route/hello-openshift -o json | jq '.status.ingress'

    Example output

    # ...
    {
      "conditions": [
        {
          "lastTransitionTime": "2024-05-17T18:25:41Z",
          "status": "True",
          "type": "Admitted"
        }
      ],
      [
        {
          "host": "hello-openshift.nodeportsvc.ipi-cluster.example.com",
          "routerCanonicalHostname": "router-nodeportsvc.nodeportsvc.ipi-cluster.example.com",
          "routerName": "nodeportsvc", "wildcardPolicy": "None"
        }
      ],
    }

  10. Update the default

    IngressController
    CR to prevent the default Ingress Controller from managing the
    NodePort
    -type
    Service
    . The default Ingress Controller will continue to monitor all other cluster traffic.

    $ oc patch --type=merge -n openshift-ingress-operator ingresscontroller/default --patch '{"spec":{"namespaceSelector":{"matchExpressions":[{"key":"<key>","operator":"NotIn","values":["<value>]}]}}}'

Verification

  1. Verify that the DNS entry can route inside and outside of your cluster by entering the following command. The command outputs the IP address of the node that received the label from running the

    oc label node
    command earlier in the procedure.

    $ dig +short <svc_name>-<project_name>.<custom_ic_domain_name>
  2. To verify that your cluster uses the IP addresses from external DNS servers for DNS resolution, check the connection of your cluster by entering the following command:

    $ curl <svc_name>-<project_name>.<custom_ic_domain_name>:<port> 
    1
    1 1
    Where <port> is the node port from the NodePort-type Service. Based on example output from the oc get svc -n openshift-ingress command, the 80:32432/TCP HTTP route means that 32432 is the node port.

    Output example

    Hello OpenShift!

27.5. Configuring ingress cluster traffic using a load balancer

OpenShift Container Platform provides methods for communicating from outside the cluster with services running in the cluster. This method uses a load balancer.

27.5.1. Using a load balancer to get traffic into the cluster

If you do not need a specific external IP address, you can configure a load balancer service to allow external access to an OpenShift Container Platform cluster.

A load balancer service allocates a unique IP. The load balancer has a single edge router IP, which can be a virtual IP (VIP), but is still a single machine for initial load balancing.

Note

If a pool is configured, it is done at the infrastructure level, not by a cluster administrator.

Note

The procedures in this section require prerequisites performed by the cluster administrator.

27.5.2. Prerequisites

Before starting the following procedures, the administrator must:

  • Set up the external port to the cluster networking environment so that requests can reach the cluster.
  • Make sure there is at least one user with cluster admin role. To add this role to a user, run the following command:

    $ oc adm policy add-cluster-role-to-user cluster-admin username
  • Have an OpenShift Container Platform cluster with at least one master and at least one node and a system outside the cluster that has network access to the cluster. This procedure assumes that the external system is on the same subnet as the cluster. The additional networking required for external systems on a different subnet is out-of-scope for this topic.

27.5.3. Creating a project and service

If the project and service that you want to expose does not exist, create the project and then create the service.

If the project and service already exists, skip to the procedure on exposing the service to create a route.

Prerequisites

  • Install the OpenShift CLI (
    oc
    ) and log in as a cluster administrator.

Procedure

  1. Create a new project for your service by running the

    oc new-project
    command:

    $ oc new-project <project_name>
  2. Use the

    oc new-app
    command to create your service:

    $ oc new-app nodejs:12~https://github.com/sclorg/nodejs-ex.git
  3. To verify that the service was created, run the following command:

    $ oc get svc -n <project_name>

    Example output

    NAME        TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    nodejs-ex   ClusterIP   172.30.197.157   <none>        8080/TCP   70s

    Note

    By default, the new service does not have an external IP address.

27.5.4. Exposing the service by creating a route

You can expose the service as a route by using the

oc expose
command.

Prerequisites

  • You logged into OpenShift Container Platform.

Procedure

  1. Log in to the project where the service you want to expose is located:

    $ oc project <project_name>
  2. Run the

    oc expose service
    command to expose the route:

    $ oc expose service nodejs-ex

    Example output

    route.route.openshift.io/nodejs-ex exposed

  3. To verify that the service is exposed, you can use a tool, such as

    curl
    to check that the service is accessible from outside the cluster.

    1. To find the hostname of the route, enter the following command:

      $ oc get route

      Example output

      NAME        HOST/PORT                        PATH   SERVICES    PORT       TERMINATION   WILDCARD
      nodejs-ex   nodejs-ex-myproject.example.com         nodejs-ex   8080-tcp                 None

    2. To check that the host responds to a GET request, enter the following command:

      Example curl command

      $ curl --head nodejs-ex-myproject.example.com

      Example output

      HTTP/1.1 200 OK
      ...

27.5.5. Creating a load balancer service

Use the following procedure to create a load balancer service.

Prerequisites

  • Make sure that the project and service you want to expose exist.
  • Your cloud provider supports load balancers.

Procedure

To create a load balancer service:

  1. Log in to OpenShift Container Platform.
  2. Load the project where the service you want to expose is located.

    $ oc project project1
  3. Open a text file on the control plane node and paste the following text, editing the file as needed:

    Sample load balancer configuration file

    apiVersion: v1
    kind: Service
    metadata:
      name: egress-2 
    1
    
    spec:
      ports:
      - name: db
        port: 3306 
    2
    
      loadBalancerIP:
      loadBalancerSourceRanges: 
    3
    
      - 10.0.0.0/8
      - 192.168.0.0/16
      type: LoadBalancer 
    4
    
      selector:
        name: mysql 
    5

    1
    Enter a descriptive name for the load balancer service.
    2
    Enter the same port that the service you want to expose is listening on.
    3
    Enter a list of specific IP addresses to restrict traffic through the load balancer. This field is ignored if the cloud-provider does not support the feature.
    4
    Enter Loadbalancer as the type.
    5
    Enter the name of the service.
    Note

    To restrict the traffic through the load balancer to specific IP addresses, it is recommended to use the Ingress Controller field

    spec.endpointPublishingStrategy.loadBalancer.allowedSourceRanges
    . Do not set the
    loadBalancerSourceRanges
    field.

  4. Save and exit the file.
  5. Run the following command to create the service:

    $ oc create -f <file-name>

    For example:

    $ oc create -f mysql-lb.yaml
  6. Execute the following command to view the new service:

    $ oc get svc

    Example output

    NAME       TYPE           CLUSTER-IP      EXTERNAL-IP                             PORT(S)          AGE
    egress-2   LoadBalancer   172.30.22.226   ad42f5d8b303045-487804948.example.com   3306:30357/TCP   15m

    The service has an external IP address automatically assigned if there is a cloud provider enabled.

  7. On the master, use a tool, such as cURL, to make sure you can reach the service using the public IP address:

    $ curl <public-ip>:<port>

    For example:

    $ curl 172.29.121.74:3306

    The examples in this section use a MySQL service, which requires a client application. If you get a string of characters with the

    Got packets out of order
    message, you are connecting with the service:

    If you have a MySQL client, log in with the standard CLI command:

    $ mysql -h 172.30.131.89 -u admin -p

    Example output

    Enter password:
    Welcome to the MariaDB monitor.  Commands end with ; or \g.
    
    MySQL [(none)]>

27.6. Configuring ingress cluster traffic on AWS

OpenShift Container Platform provides methods for communicating from outside the cluster with services running in the cluster. This method uses load balancers on AWS, specifically a Network Load Balancer (NLB) or a Classic Load Balancer (CLB). Both types of load balancers can forward the client’s IP address to the node, but a CLB requires proxy protocol support, which OpenShift Container Platform automatically enables.

There are two ways to configure an Ingress Controller to use an NLB:

  1. By force replacing the Ingress Controller that is currently using a CLB. This deletes the
    IngressController
    object and an outage will occur while the new DNS records propagate and the NLB is being provisioned.
  2. By editing an existing Ingress Controller that uses a CLB to use an NLB. This changes the load balancer without having to delete and recreate the
    IngressController
    object.

Both methods can be used to switch from an NLB to a CLB.

You can configure these load balancers on a new or existing AWS cluster.

27.6.1. Configuring Classic Load Balancer timeouts on AWS

OpenShift Container Platform provides a method for setting a custom timeout period for a specific route or Ingress Controller. Additionally, an AWS Classic Load Balancer (CLB) has its own timeout period with a default time of 60 seconds.

If the timeout period of the CLB is shorter than the route timeout or Ingress Controller timeout, the load balancer can prematurely terminate the connection. You can prevent this problem by increasing both the timeout period of the route and CLB.

27.6.1.1. Configuring route timeouts

You can configure the default timeouts for an existing route when you have services in need of a low timeout, which is required for Service Level Availability (SLA) purposes, or a high timeout, for cases with a slow back end.

Important

If you configured a user-managed external load balancer in front of your OpenShift Container Platform cluster, ensure that the timeout value for the user-managed external load balancer is higher than the timeout value for the route. This configuration prevents network congestion issues over the network that your cluster uses.

Prerequisites

  • You need a deployed Ingress Controller on a running cluster.

Procedure

  1. Using the

    oc annotate
    command, add the timeout to the route:

    $ oc annotate route <route_name> \
        --overwrite haproxy.router.openshift.io/timeout=<timeout><time_unit> 
    1
    1
    Supported time units are microseconds (us), milliseconds (ms), seconds (s), minutes (m), hours (h), or days (d).

    The following example sets a timeout of two seconds on a route named

    myroute
    :

    $ oc annotate route myroute --overwrite haproxy.router.openshift.io/timeout=2s

27.6.1.2. Configuring Classic Load Balancer timeouts

You can configure the default timeouts for a Classic Load Balancer (CLB) to extend idle connections.

Prerequisites

  • You must have a deployed Ingress Controller on a running cluster.

Procedure

  1. Set an AWS connection idle timeout of five minutes for the default

    ingresscontroller
    by running the following command:

    $ oc -n openshift-ingress-operator patch ingresscontroller/default \
        --type=merge --patch='{"spec":{"endpointPublishingStrategy": \
        {"type":"LoadBalancerService", "loadBalancer": \
        {"scope":"External", "providerParameters":{"type":"AWS", "aws": \
        {"type":"Classic", "classicLoadBalancer": \
        {"connectionIdleTimeout":"5m"}}}}}}}'
  2. Optional: Restore the default value of the timeout by running the following command:

    $ oc -n openshift-ingress-operator patch ingresscontroller/default \
        --type=merge --patch='{"spec":{"endpointPublishingStrategy": \
        {"loadBalancer":{"providerParameters":{"aws":{"classicLoadBalancer": \
        {"connectionIdleTimeout":null}}}}}}}'
Note

You must specify the

scope
field when you change the connection timeout value unless the current scope is already set. When you set the
scope
field, you do not need to do so again if you restore the default timeout value.

OpenShift Container Platform provides methods for communicating from outside the cluster with services that run in the cluster. One such method uses a Network Load Balancer (NLB). You can configure an NLB on a new or existing AWS cluster.

You can switch the Ingress Controller that is using a Classic Load Balancer (CLB) to one that uses a Network Load Balancer (NLB) on AWS.

Switching between these load balancers will not delete the

IngressController
object.

Warning

This procedure might cause the following issues:

  • An outage that can last several minutes due to new DNS records propagation, new load balancers provisioning, and other factors. IP addresses and canonical names of the Ingress Controller load balancer might change after applying this procedure.
  • Leaked load balancer resources due to a change in the annotation of the service.

Procedure

  1. Modify the existing Ingress Controller that you want to switch to using an NLB. This example assumes that your default Ingress Controller has an

    External
    scope and no other customizations:

    Example ingresscontroller.yaml file

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      creationTimestamp: null
      name: default
      namespace: openshift-ingress-operator
    spec:
      endpointPublishingStrategy:
        loadBalancer:
          scope: External
          providerParameters:
            type: AWS
            aws:
              type: NLB
        type: LoadBalancerService

    Note

    If you do not specify a value for the

    spec.endpointPublishingStrategy.loadBalancer.providerParameters.aws.type
    field, the Ingress Controller uses the
    spec.loadBalancer.platform.aws.type
    value from the cluster
    Ingress
    configuration that was set during installation.

    Tip

    If your Ingress Controller has other customizations that you want to update, such as changing the domain, consider force replacing the Ingress Controller definition file instead.

  2. Apply the changes to the Ingress Controller YAML file by running the command:

    $ oc apply -f ingresscontroller.yaml

    Expect several minutes of outages while the Ingress Controller updates.

You can switch the Ingress Controller that is using a Network Load Balancer (NLB) to one that uses a Classic Load Balancer (CLB) on AWS.

Switching between these load balancers will not delete the

IngressController
object.

Warning

This procedure might cause an outage that can last several minutes due to new DNS records propagation, new load balancers provisioning, and other factors. IP addresses and canonical names of the Ingress Controller load balancer might change after applying this procedure.

Procedure

  1. Modify the existing Ingress Controller that you want to switch to using a CLB. This example assumes that your default Ingress Controller has an

    External
    scope and no other customizations:

    Example ingresscontroller.yaml file

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      creationTimestamp: null
      name: default
      namespace: openshift-ingress-operator
    spec:
      endpointPublishingStrategy:
        loadBalancer:
          scope: External
          providerParameters:
            type: AWS
            aws:
              type: Classic
        type: LoadBalancerService

    Note

    If you do not specify a value for the

    spec.endpointPublishingStrategy.loadBalancer.providerParameters.aws.type
    field, the Ingress Controller uses the
    spec.loadBalancer.platform.aws.type
    value from the cluster
    Ingress
    configuration that was set during installation.

    Tip

    If your Ingress Controller has other customizations that you want to update, such as changing the domain, consider force replacing the Ingress Controller definition file instead.

  2. Apply the changes to the Ingress Controller YAML file by running the command:

    $ oc apply -f ingresscontroller.yaml

    Expect several minutes of outages while the Ingress Controller updates.

You can replace an Ingress Controller that is using a Classic Load Balancer (CLB) with one that uses a Network Load Balancer (NLB) on AWS.

Warning

This procedure might cause the following issues:

  • An outage that can last several minutes due to new DNS records propagation, new load balancers provisioning, and other factors. IP addresses and canonical names of the Ingress Controller load balancer might change after applying this procedure.
  • Leaked load balancer resources due to a change in the annotation of the service.

Procedure

  1. Create a file with a new default Ingress Controller. The following example assumes that your default Ingress Controller has an

    External
    scope and no other customizations:

    Example ingresscontroller.yml file

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      creationTimestamp: null
      name: default
      namespace: openshift-ingress-operator
    spec:
      endpointPublishingStrategy:
        loadBalancer:
          scope: External
          providerParameters:
            type: AWS
            aws:
              type: NLB
        type: LoadBalancerService

    If your default Ingress Controller has other customizations, ensure that you modify the file accordingly.

    Tip

    If your Ingress Controller has no other customizations and you are only updating the load balancer type, consider following the procedure detailed in "Switching the Ingress Controller from using a Classic Load Balancer to a Network Load Balancer".

  2. Force replace the Ingress Controller YAML file:

    $ oc replace --force --wait -f ingresscontroller.yml

    Wait until the Ingress Controller is replaced. Expect several of minutes of outages.

You can create an Ingress Controller backed by an AWS Network Load Balancer (NLB) on an existing cluster.

Prerequisites

  • You must have an installed AWS cluster.
  • PlatformStatus
    of the infrastructure resource must be AWS.

    • To verify that the

      PlatformStatus
      is AWS, run:

      $ oc get infrastructure/cluster -o jsonpath='{.status.platformStatus.type}'
      AWS

Procedure

Create an Ingress Controller backed by an AWS NLB on an existing cluster.

  1. Create the Ingress Controller manifest:

     $ cat ingresscontroller-aws-nlb.yaml

    Example output

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      name: $my_ingress_controller
    1
    
      namespace: openshift-ingress-operator
    spec:
      domain: $my_unique_ingress_domain
    2
    
      endpointPublishingStrategy:
        type: LoadBalancerService
        loadBalancer:
          scope: External
    3
    
          providerParameters:
            type: AWS
            aws:
              type: NLB

    1
    Replace $my_ingress_controller with a unique name for the Ingress Controller.
    2
    Replace $my_unique_ingress_domain with a domain name that is unique among all Ingress Controllers in the cluster. This variable must be a subdomain of the DNS name <clustername>.<domain>.
    3
    You can replace External with Internal to use an internal NLB.
  2. Create the resource in the cluster:

    $ oc create -f ingresscontroller-aws-nlb.yaml
Important

Before you can configure an Ingress Controller NLB on a new AWS cluster, you must complete the Creating the installation configuration file procedure.

You can create an Ingress Controller backed by an AWS Network Load Balancer (NLB) on a new cluster.

Prerequisites

  • Create the
    install-config.yaml
    file and complete any modifications to it.

Procedure

Create an Ingress Controller backed by an AWS NLB on a new cluster.

  1. Change to the directory that contains the installation program and create the manifests:

    $ ./openshift-install create manifests --dir <installation_directory> 
    1
    1
    For <installation_directory>, specify the name of the directory that contains the install-config.yaml file for your cluster.
  2. Create a file that is named

    cluster-ingress-default-ingresscontroller.yaml
    in the
    <installation_directory>/manifests/
    directory:

    $ touch <installation_directory>/manifests/cluster-ingress-default-ingresscontroller.yaml 
    1
    1
    For <installation_directory>, specify the directory name that contains the manifests/ directory for your cluster.

    After creating the file, several network configuration files are in the

    manifests/
    directory, as shown:

    $ ls <installation_directory>/manifests/cluster-ingress-default-ingresscontroller.yaml

    Example output

    cluster-ingress-default-ingresscontroller.yaml

  3. Open the

    cluster-ingress-default-ingresscontroller.yaml
    file in an editor and enter a custom resource (CR) that describes the Operator configuration you want:

    apiVersion: operator.openshift.io/v1
    kind: IngressController
    metadata:
      creationTimestamp: null
      name: default
      namespace: openshift-ingress-operator
    spec:
      endpointPublishingStrategy:
        loadBalancer:
          scope: External
          providerParameters:
            type: AWS
            aws:
              type: NLB
        type: LoadBalancerService
  4. Save the
    cluster-ingress-default-ingresscontroller.yaml
    file and quit the text editor.
  5. Optional: Back up the
    manifests/cluster-ingress-default-ingresscontroller.yaml
    file. The installation program deletes the
    manifests/
    directory when creating the cluster.

27.7. Configuring ingress cluster traffic for a service external IP

You can use either a MetalLB implementation or an IP failover deployment to attach an ExternalIP resource to a service so that the service is available to traffic outside your OpenShift Container Platform cluster. Hosting an external IP address in this way is only applicable for a cluster installed on bare-metal hardware.

You must ensure that you correctly configure the external network infrastructure to route traffic to the service.

27.7.1. Prerequisites

27.7.2. Attaching an ExternalIP to a service

You can attach an ExternalIP resource to a service. If you configured your cluster to automatically attach the resource to a service, you might not need to manually attach an ExternalIP to the service.

The examples in the procedure use a scenario that manually attaches an ExternalIP resource to a service in a cluster with an IP failover configuration.

Procedure

  1. Confirm compatible IP address ranges for the ExternalIP resource by entering the following command in your CLI:

    $ oc get networks.config cluster -o jsonpath='{.spec.externalIP}{"\n"}'
    Note

    If

    autoAssignCIDRs
    is set and you did not specify a value for
    spec.externalIPs
    in the ExternalIP resource, OpenShift Container Platform automatically assigns ExternalIP to a new
    Service
    object.

  2. Choose one of the following options to attach an ExternalIP resource to the service:

    1. If you are creating a new service, specify a value in the

      spec.externalIPs
      field and array of one or more valid IP addresses in the
      allowedCIDRs
      parameter.

      Example of service YAML configuration file that supports an ExternalIP resource

      apiVersion: v1
      kind: Service
      metadata:
        name: svc-with-externalip
      spec:
        externalIPs:
          policy:
            allowedCIDRs:
            - 192.168.123.0/28

    2. If you are attaching an ExternalIP to an existing service, enter the following command. Replace

      <name>
      with the service name. Replace
      <ip_address>
      with a valid ExternalIP address. You can provide multiple IP addresses separated by commas.

      $ oc patch svc <name> -p \
        '{
          "spec": {
            "externalIPs": [ "<ip_address>" ]
          }
        }'

      For example:

      $ oc patch svc mysql-55-rhel7 -p '{"spec":{"externalIPs":["192.174.120.10"]}}'

      Example output

      "mysql-55-rhel7" patched

  3. To confirm that an ExternalIP address is attached to the service, enter the following command. If you specified an ExternalIP for a new service, you must create the service first.

    $ oc get svc

    Example output

    NAME               CLUSTER-IP      EXTERNAL-IP     PORT(S)    AGE
    mysql-55-rhel7     172.30.131.89   192.174.120.10  3306/TCP   13m

27.8. Configuring ingress cluster traffic by using a NodePort

OpenShift Container Platform provides methods for communicating from outside the cluster with services running in the cluster. This method uses a

NodePort
.

27.8.1. Using a NodePort to get traffic into the cluster

Use a

NodePort
-type
Service
resource to expose a service on a specific port on all nodes in the cluster. The port is specified in the
Service
resource’s
.spec.ports[*].nodePort
field.

Important

Using a node port requires additional port resources.

A

NodePort
exposes the service on a static port on the node’s IP address.
NodePort
s are in the
30000
to
32767
range by default, which means a
NodePort
is unlikely to match a service’s intended port. For example, port
8080
may be exposed as port
31020
on the node.

The administrator must ensure the external IP addresses are routed to the nodes.

NodePort
s and external IPs are independent and both can be used concurrently.

Note

The procedures in this section require prerequisites performed by the cluster administrator.

27.8.2. Prerequisites

Before starting the following procedures, the administrator must:

  • Set up the external port to the cluster networking environment so that requests can reach the cluster.
  • Make sure there is at least one user with cluster admin role. To add this role to a user, run the following command:

    $ oc adm policy add-cluster-role-to-user cluster-admin <user_name>
  • Have an OpenShift Container Platform cluster with at least one master and at least one node and a system outside the cluster that has network access to the cluster. This procedure assumes that the external system is on the same subnet as the cluster. The additional networking required for external systems on a different subnet is out-of-scope for this topic.

27.8.3. Creating a project and service

If the project and service that you want to expose does not exist, create the project and then create the service.

If the project and service already exists, skip to the procedure on exposing the service to create a route.

Prerequisites

  • Install the OpenShift CLI (
    oc
    ) and log in as a cluster administrator.

Procedure

  1. Create a new project for your service by running the

    oc new-project
    command:

    $ oc new-project <project_name>
  2. Use the

    oc new-app
    command to create your service:

    $ oc new-app nodejs:12~https://github.com/sclorg/nodejs-ex.git
  3. To verify that the service was created, run the following command:

    $ oc get svc -n <project_name>

    Example output

    NAME        TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    nodejs-ex   ClusterIP   172.30.197.157   <none>        8080/TCP   70s

    Note

    By default, the new service does not have an external IP address.

27.8.4. Exposing the service by creating a route

You can expose the service as a route by using the

oc expose
command.

Prerequisites

  • You logged into OpenShift Container Platform.

Procedure

  1. Log in to the project where the service you want to expose is located:

    $ oc project <project_name>
  2. To expose a node port for the application, modify the custom resource definition (CRD) of a service by entering the following command:

    $ oc edit svc <service_name>

    Example output

    spec:
      ports:
      - name: 8443-tcp
        nodePort: 30327 
    1
    
        port: 8443
        protocol: TCP
        targetPort: 8443
      sessionAffinity: None
      type: NodePort 
    2

    1
    Optional: Specify the node port range for the application. By default, OpenShift Container Platform selects an available port in the 30000-32767 range.
    2
    Define the service type.
  3. Optional: To confirm the service is available with a node port exposed, enter the following command:

    $ oc get svc -n myproject

    Example output

    NAME                TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
    nodejs-ex           ClusterIP   172.30.217.127   <none>        3306/TCP         9m44s
    nodejs-ex-ingress   NodePort    172.30.107.72    <none>        3306:31345/TCP   39s

  4. Optional: To remove the service created automatically by the

    oc new-app
    command, enter the following command:

    $ oc delete svc nodejs-ex

Verification

  • To check that the service node port is updated with a port in the

    30000-32767
    range, enter the following command:

    $ oc get svc

    In the following example output, the updated port is

    30327
    :

    Example output

    NAME    TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
    httpd   NodePort   172.xx.xx.xx    <none>        8443:30327/TCP   109s

You can specify a list of IP address ranges for the

IngressController
. This restricts access to the load balancer service when the
endpointPublishingStrategy
is
LoadBalancerService
.

27.9.1. Configuring load balancer allowed source ranges

You can enable and configure the

spec.endpointPublishingStrategy.loadBalancer.allowedSourceRanges
field. By configuring load balancer allowed source ranges, you can limit the access to the load balancer for the Ingress Controller to a specified list of IP address ranges. The Ingress Operator reconciles the load balancer Service and sets the
spec.loadBalancerSourceRanges
field based on
AllowedSourceRanges
.

Note

If you have already set the

spec.loadBalancerSourceRanges
field or the load balancer service anotation
service.beta.kubernetes.io/load-balancer-source-ranges
in a previous version of OpenShift Container Platform, Ingress Controller starts reporting
Progressing=True
after an upgrade. To fix this, set
AllowedSourceRanges
that overwrites the
spec.loadBalancerSourceRanges
field and clears the
service.beta.kubernetes.io/load-balancer-source-ranges
annotation. Ingress Controller starts reporting
Progressing=False
again.

Prerequisites

  • You have a deployed Ingress Controller on a running cluster.

Procedure

  • Set the allowed source ranges API for the Ingress Controller by running the following command:

    $ oc -n openshift-ingress-operator patch ingresscontroller/default \
        --type=merge --patch='{"spec":{"endpointPublishingStrategy": \
        {"type":"LoadBalancerService", "loadbalancer": \
        {"scope":"External", "allowedSourceRanges":["0.0.0.0/0"]}}}}' 
    1
    1
    The example value 0.0.0.0/0 specifies the allowed source range.

27.9.2. Migrating to load balancer allowed source ranges

If you have already set the annotation

service.beta.kubernetes.io/load-balancer-source-ranges
, you can migrate to load balancer allowed source ranges. When you set the
AllowedSourceRanges
, the Ingress Controller sets the
spec.loadBalancerSourceRanges
field based on the
AllowedSourceRanges
value and unsets the
service.beta.kubernetes.io/load-balancer-source-ranges
annotation.

Note

If you have already set the

spec.loadBalancerSourceRanges
field or the load balancer service anotation
service.beta.kubernetes.io/load-balancer-source-ranges
in a previous version of OpenShift Container Platform, the Ingress Controller starts reporting
Progressing=True
after an upgrade. To fix this, set
AllowedSourceRanges
that overwrites the
spec.loadBalancerSourceRanges
field and clears the
service.beta.kubernetes.io/load-balancer-source-ranges
annotation. The Ingress Controller starts reporting
Progressing=False
again.

Prerequisites

  • You have set the
    service.beta.kubernetes.io/load-balancer-source-ranges
    annotation.

Procedure

  1. Ensure that the

    service.beta.kubernetes.io/load-balancer-source-ranges
    is set:

    $ oc get svc router-default -n openshift-ingress -o yaml

    Example output

    apiVersion: v1
    kind: Service
    metadata:
      annotations:
        service.beta.kubernetes.io/load-balancer-source-ranges: 192.168.0.1/32

  2. Ensure that the

    spec.loadBalancerSourceRanges
    field is unset:

    $ oc get svc router-default -n openshift-ingress -o yaml

    Example output

    ...
    spec:
      loadBalancerSourceRanges:
      - 0.0.0.0/0
    ...

  3. Update your cluster to OpenShift Container Platform 4.14.
  4. Set the allowed source ranges API for the

    ingresscontroller
    by running the following command:

    $ oc -n openshift-ingress-operator patch ingresscontroller/default \
        --type=merge --patch='{"spec":{"endpointPublishingStrategy": \
        {"loadBalancer":{"allowedSourceRanges":["0.0.0.0/0"]}}}}' 
    1
    1
    The example value 0.0.0.0/0 specifies the allowed source range.

27.10. Patching existing ingress objects

You can update or modify the following fields of existing

Ingress
objects without recreating the objects or disrupting services to them:

  • Specifications
  • Host
  • Path
  • Backend services
  • SSL/TLS settings
  • Annotations

The

ingressClassName
field specifies the name of the
IngressClass
object. You must define the
ingressClassName
field for each
Ingress
object.

If you have not defined the

ingressClassName
field for an
Ingress
object, you could experience routing issues. After 24 hours, you will receive an
ingressWithoutClassName
alert to remind you to set the
ingressClassName
field.

Procedure

Patch the

Ingress
objects with a completed
ingressClassName
field to ensure proper routing and functionality.

  1. List all

    IngressClass
    objects:

    $ oc get ingressclass
  2. List all

    Ingress
    objects in all namespaces:

    $ oc get ingress -A
  3. Patch the

    Ingress
    object:

    $ oc patch ingress/<ingress_name> --type=merge --patch '{"spec":{"ingressClassName":"openshift-default"}}'

    Replace

    <ingress_name>
    with the name of the
    Ingress
    object. This command patches the
    Ingress
    object to include the desired ingress class name.

Red Hat logoGithubredditYoutubeTwitter

Lernen

Testen, kaufen und verkaufen

Communitys

Über Red Hat Dokumentation

Wir helfen Red Hat Benutzern, mit unseren Produkten und Diensten innovativ zu sein und ihre Ziele zu erreichen – mit Inhalten, denen sie vertrauen können. Entdecken Sie unsere neuesten Updates.

Mehr Inklusion in Open Source

Red Hat hat sich verpflichtet, problematische Sprache in unserem Code, unserer Dokumentation und unseren Web-Eigenschaften zu ersetzen. Weitere Einzelheiten finden Sie in Red Hat Blog.

Über Red Hat

Wir liefern gehärtete Lösungen, die es Unternehmen leichter machen, plattform- und umgebungsübergreifend zu arbeiten, vom zentralen Rechenzentrum bis zum Netzwerkrand.

Theme

© 2026 Red Hat
Nach oben