Add redis-ha chart
Summary
Add redis-ha chart to provide a HA variant of the existing redis chart. To make use of this chart, in place of redis, set redis.enabled: false and redis-ha.enabled: true. The added chart is based on https://kubernetes-charts.storage.googleapis.com/redis-ha-1.0.0.tgz, which is designed as a StatefulSet with persistence.
Decisions
I did need to fork the image used in the chart to make redis-sentinel use auth. The chart assumed an envirnoment variable so I had to convert the entrypoint script to use the mounted secret file. Forked image is hosted as a part of CNG repository, merged at gitlab-org/build/CNG!60 (merged)
For the sake of simplicity across charts, redis-ha shares the redis name via nameOverride. This allows the two charts to be drop-in replacements for each other.
Follow-up items
- https://gitlab.com/charts/helm.gitlab.io/issues/325 Redis/Redis-ha charts can both be deployed at the same time to unknown effect