Install highly available Redis with Sentinel

1. Install the Redis Operator from the OT-Container-Kit Helm repository:

   helm install redis-operator redis-operator \
         --repo https://ot-container-kit.github.io/helm-charts \
         --set featureGates.GenerateConfigInInitContainer=true
   

2. Generate a strong, random password for authenticating with Redis:

   PASSWORD=$(LC_ALL=C tr -dc A-Za-z0-9 </dev/urandom | head -c 24)
   

3. Create a Kubernetes secret to securely store the password:

   kubectl create secret generic msr-redis-secret \
      --from-literal=REDIS_PASSWORD=${PASSWORD}
   

4. Deploy the Redis with Sentinel instance:

   Note

   Set clusterSize and sentinel.size to the desired number of Redis nodes.

   helm install msr-redis redis-replication \
       --repo https://ot-container-kit.github.io/helm-charts \
       --set redisReplication.clusterSize=3 \
       --set redisReplication.image=quay.io/opstree/redis \
       --set redisReplication.tag=v7.2.13 \
       --set redisReplication.redisSecret.secretName=msr-redis-secret \
       --set redisReplication.redisSecret.secretKey=REDIS_PASSWORD \
       --set podSecurityContext.runAsUser=1000 \
       --set podSecurityContext.fsGroup=1000 \
       --set sentinel.enabled=true \
       --set sentinel.size=3 \
       --set sentinel.image=quay.io/opstree/redis-sentinel \
       --set sentinel.tag=v7.2.13 \
       --set storageSpec.volumeClaimTemplate.spec.accessModes={ReadWriteOnce} \
       --set storageSpec.volumeClaimTemplate.spec.resources.requests.storage=8Gi
   

5. Retrieve the connection details for the Redis service:

   Get the Sentinel master name:

   kubectl -n default get redisreplication msr-redis -o jsonpath='{.status.connectionInfo. masterName}{"\n"}'
   

   Get the Sentinel headless service's name and port number:

   kubectl get svc | grep redis
   
   i.e.
   msr-redis                ClusterIP   10.96.169.88    <none>        6379/TCP                     34s
   msr-redis-additional     ClusterIP   10.96.57.50     <none>        6379/TCP                     34s
   msr-redis-headless       ClusterIP   None            <none>        6379/TCP                     34s
   msr-redis-master         ClusterIP   10.96.57.51     <none>        6379/TCP                     34s
   msr-redis-replica        ClusterIP   10.96.33.204    <none>        6379/TCP                     34s
   msr-redis-s-hl           ClusterIP   None            <none>        26379/TCP     
   

   In the example above, msr-redis-s-hl is Sentinel headless service which uses port 26379.

6. In values.yml, configure the Redis connection fields using the Sentinel service, port, and master name:

   • addr — Comma-separated list of Sentinel pod addresses in the following format: <pod-name>.<headless-service-name>.<namespace>.svc.cluster.local:<port>
   • sentinelMasterSet — Master name defined during Sentinel deployment (for example, mymaster).

   Example configuration:

   redis:
       type: external
       external:
           addr: "msr-redis-s-0.msr-redis-s-hl.default.svc.cluster.local:26379,msr-redis-s-1.msr-redis-s-hl.default.svc.cluster.local:26379,msr-redis-s-2.msr-redis-s-hl.default.svc.cluster.local:26379"
           existingSecret: msr-redis-secret
           sentinelMasterSet: "mymaster"
   

Upgrade highly available Redis

1. Verify Redis version:

   kubectl get pod <Redis Pod> -o jsonpath='{.spec.containers[*].image}'
   kubectl get pod <Sentinel Pod> -o jsonpath='{.spec.containers[*].image}'
   

2. Upgrade Redis:

   helm upgrade msr-redis redis-replication \
       --repo https://ot-container-kit.github.io/helm-charts \
       --set redisReplication.clusterSize=3 \
       --set redisReplication.image=quay.io/opstree/redis \
       --set redisReplication.tag=v7.2.13 \
       --set redisReplication.redisSecret.secretName=msr-redis-secret \
       --set redisReplication.redisSecret.secretKey=REDIS_PASSWORD \
       --set podSecurityContext.runAsUser=1000 \
       --set podSecurityContext.fsGroup=1000 \
       --set sentinel.enabled=true \
       --set sentinel.size=3 \
       --set sentinel.image=quay.io/opstree/redis-sentinel \
       --set sentinel.tag=v7.2.13 \
       --set storageSpec.volumeClaimTemplate.spec.accessModes={ReadWriteOnce} \
       --set storageSpec.volumeClaimTemplate.spec.resources.requests.storage=8Gi
   

   Note

   Mirantis recommends Redis 7.2.11 or later within 7.2.x branch. The validated versions are 7.2.11, 7.2.12, and 7.2.13. For the full list of available versions, see the redis-operator page.