Configuring multi-network policy

As a cluster administrator, you can configure network policy for additional networks.

Differences between multi-network policy and network policy

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

• You must use the MultiNetworkPolicy API:

  apiVersion: k8s.cni.cncf.io/v1beta1
  kind: MultiNetworkPolicy

• You must use the multi-networkpolicy resource name when using the CLI to interact with multi-network policies. For example, you can view a multi-network policy object with the oc get multi-networkpolicy <name> command where <name> is the name of a multi-network policy.

• You must specify an annotation with the name of the network attachment definition that defines the macvlan additional network:

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

  where:

  <network_name>

  Specifies the name of a network attachment definition.

Enabling multi-network policy for the cluster

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

Prerequisites

• Install the OpenShift CLI (oc).

• Log in to the cluster with a user with cluster-admin privileges.

Procedure

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

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

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

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

   Example output

   network.operator.openshift.io/cluster patched

Working with multi-network policy

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

Prerequisites

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

Creating a multi-network policy

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

Prerequisites

• Your cluster uses a cluster network provider that supports NetworkPolicy objects, such as the OVN-Kubernetes network provider or the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

• You installed the OpenShift CLI (oc).

• You are logged in to the cluster with a user with cluster-admin privileges.

• You are working in the namespace that the multi-network policy applies to.

Procedure

1. Create a policy rule:

   1. Create a <policy_name>.yaml file:

      $ touch <policy_name>.yaml

      where:

      <policy_name>

      Specifies the multi-network policy file name.

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

      Deny ingress from all pods in all namespaces

      apiVersion: k8s.cni.cncf.io/v1beta1
      kind: MultiNetworkPolicy
      metadata:
        name: deny-by-default
        annotations:
          k8s.v1.cni.cncf.io/policy-for: <network_name>
      spec:
        podSelector:
        ingress: []

      where

      <network_name>

      Specifies the name of a network attachment definition.

      Allow ingress from all pods in the same namespace

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

      where

      <network_name>

      Specifies the name of a network attachment definition.

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

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

   where:

   <policy_name>

   Specifies the multi-network policy file name.

   <namespace>

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

   Example output

   multinetworkpolicy.k8s.cni.cncf.io/default-deny created

Editing a multi-network policy

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

Prerequisites

• Your cluster uses a cluster network provider that supports NetworkPolicy objects, such as the OVN-Kubernetes network provider or the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

• You installed the OpenShift CLI (oc).

• You are logged in to the cluster with a user with cluster-admin privileges.

• You are working in the namespace where the multi-network policy exists.

Procedure

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

   $ oc get multi-networkpolicy

   where:

   <namespace>

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

2. Edit the multi-network policy object.

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

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

     where:

     <namespace>

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

     <policy_file>

     Specifies the name of the file containing the network policy.

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

     $ oc edit multi-networkpolicy <policy_name> -n <namespace>

     where:

     <policy_name>

     Specifies the name of the network policy.

     <namespace>

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

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

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

   where:

   <policy_name>

   Specifies the name of the multi-network policy.

   <namespace>

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

Viewing multi-network policies

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

Prerequisites

• You installed the OpenShift CLI (oc).

• You are logged in to the cluster with a user with cluster-admin privileges.

• You are working in the namespace where the multi-network policy exists.

Procedure

• List multi-network policies in a namespace:

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

    $ oc get multi-networkpolicy

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

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

    where:

    <policy_name>

    Specifies the name of the multi-network policy to inspect.

    <namespace>

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

Deleting a multi-network policy

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

Prerequisites

• Your cluster uses a cluster network provider that supports NetworkPolicy objects, such as the OVN-Kubernetes network provider or the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

• You installed the OpenShift CLI (oc).

• You are logged in to the cluster with a user with cluster-admin privileges.

• You are working in the namespace where the multi-network policy exists.

Procedure

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

  $ oc delete multi-networkpolicy <policy_name> -n <namespace>

  where:

  <policy_name>

  Specifies the name of the multi-network policy.

  <namespace>

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

  Example output

  multinetworkpolicy.k8s.cni.cncf.io/default-deny deleted

Additional resources

• About network policy

• Understanding multiple networks

• Configuring a macvlan network