Name and Version

bitnami/redis 20.0.5

What architecture are you using?

amd64

What steps will reproduce the bug?

• run chart with useHostnames=false (due to DNS issues causing tilt mode)
• enable sentinel
• enable masterService

Are you using any custom parameters or values?

useHostnames: false
sentinel:
  enabled: true
  masterService:
    enabled: true

What is the expected behavior?

master pod is labeled with isMaster="true"

What do you see instead?

no such label on master

Additional information

kubectl uses the content of /etc/shared/current for the pod selector in update-master-label.sh.
The content of /etc/shared/current is written by sentinel from ${REDIS_MASTER_HOST/.*} in start-sentinel.sh.
when using useHostnames=false REDIS_MASTER_HOST contains not redis-node-0.redis.svc.cluster.local, which would return redis-node-0 as current, but instead the IP address e.g. 172.22.140.140 which returns 172 as current.
thus kubectl matches no pod and updates no labels.
Unfortunately, the output of kubectl is also not logged - only the echo statement with new master elected, updating label(s)....
Patching the script configmap with echo "$(< "/etc/shared/current")" helped to debug this as it returned 172 instead of redis-node-0.

This also applies to the delete patch for the label app.kubernetes.io/role which will be fixed in 20.0.6 (annotation -> label).

To fix this either sentinel writes a non-resolved value for REDIS_MASTER_HOST into /etc/shared/current
or the kubectl script looks up the pod by IP if current is numerical. such as:
kubectl get -n <namespace> --output json pods | jq '.items[] | select(.status.podIP=="<IP>")' | jq .metadata.name
though this would likely require further RBAC permissions.