Red Hat build of MicroShift

Configure IPv6 single-stack networking

To run MicroShift with IPv6-only networking, you can update the service configuration file and set the network section with your cluster and service CIDRs. You can verify the configuration by checking that pods and services use IPv6 addresses.

Prerequisites

You installed the OpenShift CLI (oc).
You have root access to the node.
Your node uses the OVN-Kubernetes network plugin.
The host has an IPv6 address and IPv6 routes, including the default.

Procedure

If you have not done so, make a copy of the provided config.yaml.default file in the /etc/microshift/ directory, renaming it config.yaml.
Keep the new MicroShift config.yaml in the /etc/microshift/ directory. Your config.yaml file is read every time the MicroShift service starts.

After you create it, the config.yaml file takes precedence over built-in settings.
Replace the default values in the network section of the MicroShift YAML with your valid values.
Example single-stack IPv6 networking configuration
```
apiServer:
# ...
network:
  clusterNetwork:
  - fd01::/48
  serviceNetwork:
  - fd02::/112
node:
  nodeIP: 2600:1f14:1c48:ee00:2d76:3190:5bc2:5aef
# ...
```
where:

networking.clusterNetwork

Specifies a clusterNetwork address with a CIDR value that is less than 64. For example, fd01::/48.

network.serviceNetwork

Specifies an IPv6 CIDR with a prefix of 112, for example, fd02::/112. Kubernetes uses only the lowest 16 bits. For a prefix of 112, IP addresses are assigned from 112 to 128 bits.

node.nodeIP

Specifies a node IP address. Valid values are IP addresses in the IPv6 address family. You must only specify an IPv6 address when an IPv4 network is also present. If an IPv4 network is not present, the MicroShift service automatically fills in this value upon restart.
Complete any other configurations you require, then start MicroShift by running the following command:
```
$ sudo systemctl start microshift
```

Verification

Retrieve the networks defined in the node resource by running the following command:
```
$ oc get node -o jsonpath='{.items[].spec.podCIDRs[]}'
```
Example output
```
fd01::/48
```

Retrieve the status of the pods by running the following command:

$ oc get pod -A -o wide

Example output

NAMESPACE                  NAME                                      READY   STATUS    RESTARTS   AGE   IP                      NODE           NOMINATED NODE   READINESS GATES
kube-system                csi-snapshot-controller-bb7cb654b-rqrt6   1/1     Running   0          65s   fd01:0:0:1::5           microshift-9   <none>           <none>
openshift-dns              dns-default-cjn66                         2/2     Running   0          62s   fd01:0:0:1::9           microshift-9   <none>           <none>
openshift-dns              node-resolver-ppnjb                       1/1     Running   0          63s   2001:db9:ca7:ff::1db8   microshift-9   <none>           <none>
openshift-ingress          router-default-6d97d7b8b6-wdtmg           1/1     Running   0          61s   fd01:0:0:1::8           microshift-9   <none>           <none>
openshift-ovn-kubernetes   ovnkube-master-gfvp5                      4/4     Running   0          63s   2001:db9:ca7:ff::1db8   microshift-9   <none>           <none>
openshift-ovn-kubernetes   ovnkube-node-bnpjh                        1/1     Running   0          63s   2001:db9:ca7:ff::1db8   microshift-9   <none>           <none>
openshift-service-ca       service-ca-5d7bd9db6-j25bd                1/1     Running   0          60s   fd01:0:0:1::4           microshift-9   <none>           <none>
openshift-storage          lvms-operator-656cd9b59b-bwr47            1/1     Running   0          63s   fd01:0:0:1::7           microshift-9   <none>           <none>
openshift-storage          vg-manager-f7dmk                          1/1     Running   0          27s   fd01:0:0:1::a           microshift-9   <none>           <none>

Retrieve the status of services by running the following command:

$ oc get svc -A

Example output

NAMESPACE           NAME                            TYPE           CLUSTER-IP   EXTERNAL-IP                                             PORT(S)                      AGE
default             kubernetes                      ClusterIP      fd02::1      <none>                                                  443/TCP                      3m42s
openshift-dns       dns-default                     ClusterIP      fd02::a      <none>                                                  53/UDP,53/TCP,9154/TCP       2m58s
openshift-ingress   router-default                  LoadBalancer   fd02::f2e6   2001:db9:ca7:ff::1db8,fd01:0:0:1::2,fd02::1:0,fd69::2   80:31133/TCP,443:31996/TCP   2m58s
openshift-ingress   router-internal-default         ClusterIP      fd02::c55e   <none>                                                  80/TCP,443/TCP,1936/TCP      2m58s
openshift-storage   lvms-operator-metrics-service   ClusterIP      fd02::7afb   <none>                                                  443/TCP                      2m58s
openshift-storage   lvms-webhook-service            ClusterIP      fd02::d8dd   <none>                                                  443/TCP                      2m58s
openshift-storage   vg-manager-metrics-service      ClusterIP      fd02::fc1    <none>                                                  443/TCP                      2m58s