Add support for persistentVolumeClaimRetentionPolicy field in statefulset mode

[dferrochio]

Component(s)

collector

Is your feature request related to a problem? Please describe.

I'm not able to change the persistentVolumeClaimRetentionPolicy field in statefulset mode. I need to change the default policy to delete the PVC's when the statefulset is scaled.

Describe the solution you'd like

Solution might be an optional configuration section for the statefulset specs like this:

apiVersion: opentelemetry.io/v1beta1
kind: OpenTelemetryCollector
spec:
  mode: statefulset
  statefulset:
    spec:
      persistentVolumeClaimRetentionPolicy:
        whenDeleted: Retain
        whenScaled: Delete

Describe alternatives you've considered

No response

Additional context

No response

[davidhaja]

I am happy to help you with this.
How about instead of adding statefulset.spec.persistentVolumeClaimRetentionPolicy to the opentelemetrycollector CRD, the persistentVolumeClaimRetentionPolicy would be a just separate field(object) like:

apiVersion: opentelemetry.io/v1beta1
kind: OpenTelemetryCollector
spec:
  mode: statefulset
  persistentVolumeClaimRetentionPolicy:
    whenDeleted: Retain
    whenScaled: Delete

[dferrochio]

I am happy to help you with this. How about instead of adding statefulset.spec.persistentVolumeClaimRetentionPolicy to the opentelemetrycollector CRD, the persistentVolumeClaimRetentionPolicy would be a just separate field(object) like:

apiVersion: opentelemetry.io/v1beta1
kind: OpenTelemetryCollector
spec:
  mode: statefulset
  persistentVolumeClaimRetentionPolicy:
    whenDeleted: Retain
    whenScaled: Delete

Hi, and thanks for your propossal.

I thought on recommend that solution too. But I didn't choose it because could be less explicit and could generate some confussion to users. I prefer a solution that it's clear that only works for statefulset mode and not getting users trying to use persistentVolumeClaimRetentionPolicy field for other modes.

An intermediate solution could be:

kind: OpenTelemetryCollector
spec:
  mode: statefulset
  statefulset:
    persistentVolumeClaimRetentionPolicy:
      whenDeleted: Retain
      whenScaled: Delete

Also, your solution could work too if documentation is clear enough about the persistentVolumeClaimRetentionPolicy field only works for statefulset mode. And maybe adding a warning log if the field is used in a different mode.

[davidhaja]

Yeah, I've recommended that because AFAIK only the statefulset has this persistentVolumeClaimRetentionPolicy field.
I guess we can let the core maintainers decide what do they prefer.
@jaronoff97 @pavolloffay @swiatekm

[swiatekm]

We already have a field at top level which only applies if the mode is statefulset, so I think it's fine to do the same thing here. See

opentelemetry-operator/apis/v1beta1/common.go

Line 245 in a3feb2c

VolumeClaimTemplates []v1.PersistentVolumeClaim `json:"volumeClaimTemplates,omitempty"`

if you want to try implementing it yourself.

[davidhaja]

Sure thing.
@swiatekm Thank you for your input.
Feel free to assign this ticket to me.