Chapter 4. DNS Operator in OpenShift Container Platform

1. Use the oc get command to view the Deployment status:

   $ oc get -n openshift-dns-operator deployment/dns-operator
   NAME           READY     UP-TO-DATE   AVAILABLE   AGE
   dns-operator   1/1       1            1           23h

   ClusterOperator is the Custom Resource object which holds the current state of an operator. This object is used by operators to convey their state to the rest of the cluster.

2. Use the oc get command to view the state of the DNS Operator:

   $ oc get clusteroperator/dns
   NAME      VERSION     AVAILABLE   PROGRESSING   DEGRADED   SINCE
   dns       4.1.0-0.11  True        False         False      92m

   AVAILABLE, PROGRESSING and DEGRADED provide information about the status of the operator. AVAILABLE is True when at least 1 pod from the CoreDNS DaemonSet is reporting an Available status condition.

Procedure

1. Use the oc describe command to view the default dns:

   $ oc describe dns.operator/default
   Name:         default
   Namespace:
   Labels:       <none>
   Annotations:  <none>
   API Version:  operator.openshift.io/v1
   Kind:         DNS
   ...
   Status:
     Cluster Domain:  cluster.local 1
     Cluster IP:      172.30.0.10 2
   ...

   1

   The Cluster Domain field is the base DNS domain used to construct fully qualified Pod and Service domain names.

   2

   The Cluster IP is the address pods query for name resolution. The IP is defined as the 10th address in the Service CIDR range.

2. To find the Service CIDR of your cluster, use the oc get command:

   $ oc get networks.config/cluster -o jsonpath='{$.status.serviceNetwork}'
   [172.30.0.0/16]