README.md

Sample Migration from existing single Redis instance

Manual steps

Shutdown all dependencies before proceed

Scale down existing redis instance and delete the dc

    export REDIS_PREFIX=backend
    export REDIS_NAME=${REDIS_PREFIX}-redis
    
    oc scale --replicas=0 dc ${REDIS_NAME}
    oc delete dc,svc ${REDIS_NAME}

Create the bootstrap master and sentinel

As PV use the existing storage

    oc process -f templates/redis-master.yml \
        -p REDIS_SERVICE_PREFIX=${REDIS_PREFIX} \
        -p REDIS_IMAGE=redis-ha:latest \
        -p REDIS_PV=${REDIS_PREFIX}-storage \
        | oc create -f -

Create a new persistent storage (RWX)

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: backend-redis-rwx-storage
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

    oc create -f /tmp/storage.yml

Create the slave redis

Using the new storage create the slave redis. Wait the master pod to start up before proceed

    oc process -f templates/redis-slave.yml \
        -p REDIS_SERVICE_PREFIX=${REDIS_PREFIX} \
        -p REDIS_IMAGE=redis-ha:latest \
        -p REDIS_PV=${REDIS_NAME}-rwx-storage \
        | oc create -f -

Create the sentinel redis

    oc process -f templates/redis-sentinel.yml \
        -p REDIS_SERVICE_PREFIX=${REDIS_PREFIX} \
        -p REDIS_IMAGE=redis-ha:latest \
        | oc create -f -

Scale down the bootstrap master

    oc scale --replicas=0 dc ${REDIS_NAME}-master

Override the master data storage with the new RWX storage

   oc volume dc/${REDIS_NAME}-master --add --name=data --type=pvc --claim-name=${REDIS_NAME}-rwx-storage -m /var/lib/redis/data --overwrite

Delete the old storage

    oc delete pvc ${REDIS_NAME}-storage

Ansible Playbook

TBD