Time-based delivery for static inputs

[bozho]

Hi,

We will be running Elasticsearch (using the ECK operator) in several k8s clusters that will run different in regions/time zones.

Since upgrading an Elasticsearch cluster is a bit disruptive, and would ideally be performed during time zone's out-of-hours for each production cluster, I was wondering if time-based delivery works with static RSIP resources.

Currently, I have a ResourceSet with static input, which declares ES version to deploy, something like:

apiVersion: fluxcd.controlplane.io/v1
kind: ResourceSet
metadata:
  name: elasticsearch
  namespace: flux-system
  annotations:
    fluxcd.controlplane.io/reconcileEvery: "5m"
spec:
  wait: true
  inputs:
    - tenant: search
      elastic_version: "9.5.4"
      ...
  resources:
    ...
    - apiVersion: kustomize.toolkit.fluxcd.io/v1
      kind: Kustomization
      metadata:
        name: elastic
        namespace: elastic-<< inputs.tenant >>
      spec:
        targetNamespace: elastic-<< inputs.tenant >>
        ...
        sourceRef:
          kind: OCIRepository
          name: apps
        path: "./<< inputs.platform >>/<< inputs.environment >>"
        prune: true
        postBuild:
          substitute:
            ELASTIC_INSTANCE_NAME: << inputs.tenant >>
            ELASTIC_VERSION: << inputs.elastic_version >>
            ...

The Kustomization contains the Elasticsearch CRD, which is then used to deploy an Elasticsearch cluster instance.

Our GitOps process is tag-based: commits to master are packaged, published in the OCI registry under the latest tag and deployed to staging clusters. To deploy to production, we'd tag a commit with an appropriate semver tag, which then gets published in the OCI registry under the latest-stable tag and deployed to production clusters (essentially, the Flux D2 reference architecture workflow).

The problem with this is that this approach would deploy production changes at the (roughly) same time to all time zones, which I'd like to avoid.

Is it possible to have a static RSIP which would provide the elastic_version input to the ResourceSet and trigger changes to the value on a defined schedule?

[matheuscscp]

There's no difference in behavior for Static compared to other RSIP types regarding the schedule field, they all behave the same. If you have a non-zero window, flux-operator will only copy new values set in defaultValues to the exportedInputs inside the cron window.

[bozho]

Lovely, thank you!

This means I can set my cron schedule and time zone as a runtime info in each of the cluster instances.

What should I set the schedule to for staging clusters if I want changes to be applied immediately? Empty string or * * * * *?

[matheuscscp]

What should I set the schedule to for staging clusters if I want changes to be applied immediately? Empty string or * * * * *?

Don't set the schedule field in staging.

[bozho]

Hm, that means that I'd have to put the Elasticsearch CRD in the apps repository (created by the Kustomization in the ResourceSet above, which lives among tenants in the fleet repo) into a new ResourceSet in the apps repository, which would then take inputs from the "ES version" RSIP, which would then be patched in the production overlay in the apps repo to include the schedule.

Or is there a more elegant way?