Attaching a Pod to an additional network - Multiple networks | Networking

Adding a Pod to an additional network

As a cluster user you can attach a Pod to an additional network.

Adding a Pod to an additional network

You can add a Pod to an additional network. The Pod continues to send normal cluster related network traffic over the default network.

Prerequisites

The Pod must be in the same namespace as the additional network.
Install the OpenShift Command-line Interface (CLI), commonly known as oc.
You must log in to the cluster.

Procedure

To add a Pod with additional networks, complete the following steps:

Create the Pod resource definition and add the k8s.v1.cni.cncf.io/networks parameter to the Pod metadata mapping. The k8s.v1.cni.cncf.io/networks accepts a comma separated string of one or more NetworkAttachmentDefinition Custom Resource (CR) names:

metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: <network>[,<network>,...] (1)

1 Replace <network> with the name of the additional network to associate with the Pod. To specify more than one additional network, separate each network with a comma. Do not include whitespace between the comma. If you specify the same additional network multiple times, that Pod will have multiple network interfaces attached to that network.

In the following example, two additional networks are attached to the Pod:

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: net1,net2
spec:
  containers:
  - name: example-pod
    command: ["/bin/bash", "-c", "sleep 2000000000000"]
    image: centos/tools

Create the Pod by running the following command:
```
$ oc create -f pod.yaml
```

Optional: Confirm that the annotation exists in the Pod CR by running the following command. Replace <name> with the name of the Pod.

$ oc get pod <name> -o yaml

In the following example, the example-pod Pod is attached to the net1 additional network:

$ oc get pod example-pod -o yaml
apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: macvlan-bridge
    k8s.v1.cni.cncf.io/networks-status: |- (1)
      [{
          "name": "openshift-sdn",
          "interface": "eth0",
          "ips": [
              "10.128.2.14"
          ],
          "default": true,
          "dns": {}
      },{
          "name": "macvlan-bridge",
          "interface": "net1",
          "ips": [
              "20.2.2.100"
          ],
          "mac": "22:2f:60:a5:f8:00",
          "dns": {}
      }]
  name: example-pod
  namespace: default
spec:
  ...
status:
  ...

1	The `k8s.v1.cni.cncf.io/networks-status` parameter is a JSON array of objects. Each object describes the status of an additional network attached to the Pod. The annotation value is stored as a plain text value.