Does argo-workflows support multiple controllers with different argo version in same k8s cluster ?

[wshi5985]

It looks like argo-workflows support multiple controllers in a single k8s cluster.
https://github.com/argoproj/argo-workflows/blob/master/docs/workflow-controller-configmap.yaml#L12
Can multiple controllers in the same cluster has different argo version ?
Thanks!

[sarabala1979]

yes, you can have a different version of controllers in the same cluster. you should configure the instance-id for each controller for sharding workflows for those controllers.

[wshi5985]

we have an existing controller with argo version 2.9.5. we would like to install second controller with latest argo version v3.0.0-rc1. we noticed that there are changes on CRDs (from example, apiVersion changed from apiextensions.k8s.io/v1beta1 to apiextensions.k8s.io/v1), CRDs are global, and names are consistent.
How can we have 2 set of CRDs for different version of argo controllers ? Thanks.

[wshi5985]

not only the apiVersion changed, compare to v2.9.5, v3.0.0-rc1 CRD definition added schema/served/storage for version in multiple CRDs,
versions:

• name: v1alpha1
  schema:
  openAPIV3Schema:
  properties:
  apiVersion:
  type: string
  kind:
  type: string
  metadata:
  type: object
  spec:
  type: object
  x-kubernetes-preserve-unknown-fields: true
  required:
  - metadata
  - spec
  type: object
  served: true
  storage: true

and removed "additionalPrinterColumns" in spec for CRD workflows.argoproj.io

If we use CRD definition for v3.0.0-rc1, will it breaks anything for the first argo controller(v2.9.5) ? Thanks.

[terrytangyuan]

As @sarabala1979 mentioned above, you can configure different controllers via different instance IDs.

If you need to serve different CRDs, you should probably try running different controllers in separate namespaces and configure your CRDs with scope: Namespaced: https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definition-versioning/#specify-multiple-versions

You might also want to check out how to write a conversion webhook to convert and serve multiple versions of the CRDs: https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definition-versioning/#webhook-conversion