Pass in custom logic to Dragonfly health check

[xuekat]

We'd like to pass in custom logic to the dragonfly health check. Our use case is that we're using Dragonfly as our main metadata/feature store, and whenever we need to do a helm upgrade on our dragonfly instances, the rollout will roll out one pod at a time and perform a rudimentary health check (redis ping) on the pod, before killing the previous pod. But the new pod still needs to load an entire snapshot into memory, which could take up to 3 minutes. This is 3 minutes of down time for us, so was wondering if there was a way to also add the dataset loading check into the health check as well.

[moredure]

@xuekat Hello! Have you considered overriding the healthcheck script within your own custom image which is based on dragonfly one?