Red Hat build of MicroShift

Create a NetworkAttachmentDefinition for an additional network

You can create a NetworkAttachmentDefinition configuration file for an additional network in order to use other CNI plugins.

In this example, a bridge-type interface is used. You can also use the example workflow here that uses host-local IP address management (IPAM) to configure other supported additional network types.

If you use bridge and the dhcp IPAM, a DHCP server listening on the bridged network is required. If you are also using a firewall, configuring the firewalld service to allow DHCP traffic on the network zone is also required. You can run the firewall-cmd --remove-service=dhcp command in this case.

Prerequisites

The MicroShift Multus CNI is installed.
The OpenShift CLI (oc) is installed.
MicroShift is running.

Procedure

Optional: Verify that the MicroShift node is running with the Multus CNI by running the following command:

$ oc get pods -n openshift-multus

Example output

NAME                READY   STATUS    RESTARTS   AGE
dhcp-daemon-dfbzw   1/1     Running   0          5h
multus-rz8xc        1/1     Running   0          5h

Create a NetworkAttachmentDefinition configuration file by running the following command and using the following example file for reference:

$ oc apply -f network-attachment-definition.yaml

Example NetworkAttachmentDefinition file

apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: bridge-conf
spec:
  config: '{
      "cniVersion": "0.4.0",
      "type": "bridge",
      "bridge": "br-test",
      "mode": "bridge",
      "ipam": {
        "type": "host-local",
        "ranges": [
          [
            {
              "subnet": "10.10.0.0/24",
              "rangeStart": "10.10.0.20",
              "rangeEnd": "10.10.0.50",
              "gateway": "10.10.0.254"
             }
          ],
          [
            {
              "subnet": "fd00:IJKL:MNOP:10::0/64",
              "rangeStart": "fd00:IJKL:MNOP:10::1",
              "rangeEnd": "fd00:IJKL:MNOP:10::9"
        "dataDir": "/var/lib/cni/br-test"
      }
    }'

where:

type

Specifies a name of the CNI plugin. This example uses the bridge type.

bridge

Specifies the name of the bridge on the MicroShift host that is used. The additional interface of the pod is connected to that bridge. If the interface does not exist on the host, the Bridge CNI creates it. If the interface already exists, it is reused. In this example, the name of the interface is br-test.

ipam

Specifies the IPAM type.

ipam.ranges.

Specifies the IP address range for the additional network. IPv6 addresses can be added to the secondary interface.

Using the name of the bridge is specific to the bridge type of plugin. Other plugins use different fields in their NetworkAttachmentDefinitions. For example, the macvlan and ipvlan configurations use master to specify the host interface to attach.