9.2.2 Deploying a multirole StatefulSet

And here’s the Redis StatefulSet that references the ConfigMap

kubectl create -f Chapter09/9.2.2_StatefulSet_Redis_Multi

This time, we’ll get 3 pods, the primary and 2 replicas:

$ kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
redis-0                       1/1     Running   0          57s
redis-1                       1/1     Running   0          45s
redis-2                       0/1     Pending   0          26s

Instead of creating a local docker container, we can also just exec directly in to test.

Connecting to the primary, we can write data:

$ kubectl exec -it redis-0 -- redis-cli
127.0.0.1:6379> SET capital:australia "Canberra"
OK
127.0.0.1:6379> exit

Connecting to one of the replicas, you can read data

$ kubectl exec -it redis-1 -- redis-cli
Defaulted container "redis-container" out of: redis-container, init-redis (init)
127.0.0.1:6379> GET capital:australia
"Canberra"

But not write

127.0.0.1:6379> SET capital:usa "Washington"
(error) READONLY You can't write against a read only replica.
127.0.0.1:6379> exit