Chapter 17. Network policy

Verification

1. To create a namespace with network policies complete the following steps:

   1. Create a namespace for verification:

      $ cat <<EOF| oc create -f -
      kind: Namespace
      apiVersion: v1
      metadata:
        name: verify-audit-logging
        annotations:
          k8s.ovn.org/acl-logging: '{ "deny": "alert", "allow": "alert" }'
      EOF

      Example output

      namespace/verify-audit-logging created

   2. Enable audit logging:

      $ oc annotate namespace verify-audit-logging k8s.ovn.org/acl-logging='{ "deny": "alert", "allow": "alert" }'

      namespace/verify-audit-logging annotated

   3. Create network policies for the namespace:

      $ cat <<EOF| oc create -n verify-audit-logging -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: deny-all
      spec:
        podSelector:
          matchLabels:
        policyTypes:
        - Ingress
        - Egress
      ---
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-same-namespace
      spec:
        podSelector: {}
        policyTypes:
         - Ingress
         - Egress
        ingress:
          - from:
              - podSelector: {}
        egress:
          - to:
             - namespaceSelector:
                matchLabels:
                  namespace: verify-audit-logging
      EOF

      Example output

      networkpolicy.networking.k8s.io/deny-all created
      networkpolicy.networking.k8s.io/allow-from-same-namespace created

2. Create a pod for source traffic in the default namespace:

   $ cat <<EOF| oc create -n default -f -
   apiVersion: v1
   kind: Pod
   metadata:
     name: client
   spec:
     containers:
       - name: client
         image: registry.access.redhat.com/rhel7/rhel-tools
         command: ["/bin/sh", "-c"]
         args:
           ["sleep inf"]
   EOF

3. Create two pods in the verify-audit-logging namespace:

   $ for name in client server; do
   cat <<EOF| oc create -n verify-audit-logging -f -
   apiVersion: v1
   kind: Pod
   metadata:
     name: ${name}
   spec:
     containers:
       - name: ${name}
         image: registry.access.redhat.com/rhel7/rhel-tools
         command: ["/bin/sh", "-c"]
         args:
           ["sleep inf"]
   EOF
   done

   Example output

   pod/client created
   pod/server created

4. To generate traffic and produce network policy audit log entries, complete the following steps:

   1. Obtain the IP address for pod named server in the verify-audit-logging namespace:

      $ POD_IP=$(oc get pods server -n verify-audit-logging -o jsonpath='{.status.podIP}')

   2. Ping the IP address from the previous command from the pod named client in the default namespace and confirm that all packets are dropped:

      $ oc exec -it client -n default -- /bin/ping -c 2 $POD_IP

      Example output

      PING 10.128.2.55 (10.128.2.55) 56(84) bytes of data.
      
      --- 10.128.2.55 ping statistics ---
      2 packets transmitted, 0 received, 100% packet loss, time 2041ms

   3. Ping the IP address saved in the POD_IP shell environment variable from the pod named client in the verify-audit-logging namespace and confirm that all packets are allowed:

      $ oc exec -it client -n verify-audit-logging -- /bin/ping -c 2 $POD_IP

      Example output

      PING 10.128.0.86 (10.128.0.86) 56(84) bytes of data.
      64 bytes from 10.128.0.86: icmp_seq=1 ttl=64 time=2.21 ms
      64 bytes from 10.128.0.86: icmp_seq=2 ttl=64 time=0.440 ms
      
      --- 10.128.0.86 ping statistics ---
      2 packets transmitted, 2 received, 0% packet loss, time 1001ms
      rtt min/avg/max/mdev = 0.440/1.329/2.219/0.890 ms

5. Display the latest entries in the network policy audit log:

   $ for pod in $(oc get pods -n openshift-ovn-kubernetes -l app=ovnkube-node --no-headers=true | awk '{ print $1 }') ; do
       oc exec -it $pod -n openshift-ovn-kubernetes -- tail -4 /var/log/ovn/acl-audit-log.log
     done

   Example output

   Defaulting container name to ovn-controller.
   Use 'oc describe pod/ovnkube-node-hdb8v -n openshift-ovn-kubernetes' to see all of the containers in this pod.
   2021-06-13T19:33:11.590Z|00005|acl_log(ovn_pinctrl0)|INFO|name="verify-audit-logging_deny-all", verdict=drop, severity=alert: icmp,vlan_tci=0x0000,dl_src=0a:58:0a:80:02:39,dl_dst=0a:58:0a:80:02:37,nw_src=10.128.2.57,nw_dst=10.128.2.55,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
   2021-06-13T19:33:12.614Z|00006|acl_log(ovn_pinctrl0)|INFO|name="verify-audit-logging_deny-all", verdict=drop, severity=alert: icmp,vlan_tci=0x0000,dl_src=0a:58:0a:80:02:39,dl_dst=0a:58:0a:80:02:37,nw_src=10.128.2.57,nw_dst=10.128.2.55,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
   2021-06-13T19:44:10.037Z|00007|acl_log(ovn_pinctrl0)|INFO|name="verify-audit-logging_allow-from-same-namespace_0", verdict=allow, severity=alert: icmp,vlan_tci=0x0000,dl_src=0a:58:0a:80:02:3b,dl_dst=0a:58:0a:80:02:3a,nw_src=10.128.2.59,nw_dst=10.128.2.58,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0
   2021-06-13T19:44:11.037Z|00008|acl_log(ovn_pinctrl0)|INFO|name="verify-audit-logging_allow-from-same-namespace_0", verdict=allow, severity=alert: icmp,vlan_tci=0x0000,dl_src=0a:58:0a:80:02:3b,dl_dst=0a:58:0a:80:02:3a,nw_src=10.128.2.59,nw_dst=10.128.2.58,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=8,icmp_code=0

Procedure

1. Log in as a user with cluster-admin privileges.

2. Generate the default project template:

   $ oc adm create-bootstrap-project-template -o yaml > template.yaml

3. Use a text editor to modify the generated template.yaml file by adding objects or modifying existing objects.

4. The project template must be created in the openshift-config namespace. Load your modified template:

   $ oc create -f template.yaml -n openshift-config

5. Edit the project configuration resource using the web console or CLI.

   • Using the web console:

     1. Navigate to the Administration Cluster Settings page.
     2. Click Configuration to view all configuration resources.
     3. Find the entry for Project and click Edit YAML.

   • Using the CLI:

     1. Edit the project.config.openshift.io/cluster resource:

        $ oc edit project.config.openshift.io/cluster

6. Update the spec section to include the projectRequestTemplate and name parameters, and set the name of your uploaded project template. The default name is project-request.

   Project configuration resource with custom project template

   apiVersion: config.openshift.io/v1
   kind: Project
   metadata:
     ...
   spec:
     projectRequestTemplate:
       name: <template_name>

7. After you save your changes, create a new project to verify that your changes were successfully applied.

Procedure

1. Edit the default template for a new project by running the following command:

   $ oc edit template <project_template> -n openshift-config

   Replace <project_template> with the name of the default template that you configured for your cluster. The default template name is project-request.

2. In the template, add each NetworkPolicy object as an element to the objects parameter. The objects parameter accepts a collection of one or more objects.

   In the following example, the objects parameter collection includes several NetworkPolicy objects.

   objects:
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-same-namespace
     spec:
       podSelector: {}
       ingress:
       - from:
         - podSelector: {}
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-openshift-ingress
     spec:
       ingress:
       - from:
         - namespaceSelector:
             matchLabels:
               network.openshift.io/policy-group: ingress
       podSelector: {}
       policyTypes:
       - Ingress
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-kube-apiserver-operator
     spec:
       ingress:
       - from:
         - namespaceSelector:
             matchLabels:
               kubernetes.io/metadata.name: openshift-kube-apiserver-operator
           podSelector:
             matchLabels:
               app: kube-apiserver-operator
       policyTypes:
       - Ingress
   ...

3. Optional: Create a new project to confirm that your network policy objects are created successfully by running the following commands:

   1. Create a new project:

      $ oc new-project <project> 1

      1

      Replace <project> with the name for the project you are creating.

   2. Confirm that the network policy objects in the new project template exist in the new project:

      $ oc get networkpolicy
      NAME                           POD-SELECTOR   AGE
      allow-from-openshift-ingress   <none>         7s
      allow-from-same-namespace      <none>         7s

Procedure

1. Create the following NetworkPolicy objects:

   1. A policy named allow-from-openshift-ingress.

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-openshift-ingress
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                policy-group.network.openshift.io/ingress: ""
        podSelector: {}
        policyTypes:
        - Ingress
      EOF

      Note

      policy-group.network.openshift.io/ingress: "" is the preferred namespace selector label for OpenShift SDN. You can use the network.openshift.io/policy-group: ingress namespace selector label, but this is a legacy label.

   2. A policy named allow-from-openshift-monitoring:

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-openshift-monitoring
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                network.openshift.io/policy-group: monitoring
        podSelector: {}
        policyTypes:
        - Ingress
      EOF

   3. A policy named allow-same-namespace:

      $ cat << EOF| oc create -f -
      kind: NetworkPolicy
      apiVersion: networking.k8s.io/v1
      metadata:
        name: allow-same-namespace
      spec:
        podSelector:
        ingress:
        - from:
          - podSelector: {}
      EOF

   4. A policy named allow-from-kube-apiserver-operator:

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-kube-apiserver-operator
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                kubernetes.io/metadata.name: openshift-kube-apiserver-operator
            podSelector:
              matchLabels:
                app: kube-apiserver-operator
        policyTypes:
        - Ingress
      EOF

      For more details, see New kube-apiserver-operator webhook controller validating health of webhook.

2. Optional: To confirm that the network policies exist in your current project, enter the following command:

   $ oc describe networkpolicy

   Example output

   Name:         allow-from-openshift-ingress
   Namespace:    example1
   Created on:   2020-06-09 00:28:17 -0400 EDT
   Labels:       <none>
   Annotations:  <none>
   Spec:
     PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
     Allowing ingress traffic:
       To Port: <any> (traffic allowed to all ports)
       From:
         NamespaceSelector: network.openshift.io/policy-group: ingress
     Not affecting egress traffic
     Policy Types: Ingress
   
   
   Name:         allow-from-openshift-monitoring
   Namespace:    example1
   Created on:   2020-06-09 00:29:57 -0400 EDT
   Labels:       <none>
   Annotations:  <none>
   Spec:
     PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
     Allowing ingress traffic:
       To Port: <any> (traffic allowed to all ports)
       From:
         NamespaceSelector: network.openshift.io/policy-group: monitoring
     Not affecting egress traffic
     Policy Types: Ingress