Helm Chart PVC does not allow for multiple replicas or configuration changes

[metalsp0rk]

Background information

• Dendrite version or git SHA: 317b101
• SQLite3 or Postgres?: Postgres
• Running in Docker?: Kubernetes
• go version:
• Client used (if applicable): N/A

Description

• What is the problem: The PVC configuration for the Helm chart dendrite deployment is set to ReadWriteOnce, which prevents multiple replicas to be spun up, and additionally prevents the create -> terminate lifecycle pattern when upgrading.
• Who is affected: Anyone using the Helm chart.
• How is this bug manifesting: When attempting to upgrade the server or change configuration
• When did this first appear: After making a configuration change

Steps to reproduce

• deploy the Dendrite Helm chart
• make a configuration change
• the kubernetes control plane will then attempt to deploy a second pod, which gets stuck in containerCreating, causing a bad state, that requires the uninstallation of the helm chart and manual clean up of resources on the cluster.

I would expect multiple pods to be able to be launched simultaneously, but currently the PVC configuration prevents this.
I would be happy to submit a PR to address the change in the helm chart if a change is welcomed in this area.

[wrenix]

You chould change the updateStrategy to type: Recreate to solve your problem on change config ... (i think it usefull to change that to default, i create a PR)

An change of the helm-chart to support PVC to ReadWriteMany is possible (but current no good idea, also like to change to StatefulSet with VolumneTemplate):

dendrite does not support to be run multiple times, see: #2975
for replica higher then 1 (or an HorizontalPodAutoscaler) or during update/config change.