Changing operating_system on existing cluster does not trigger a destroy and create

[ocofaigh]

Changing the value of operating_system on existing cluster that was created using ibm_container_vpc_cluster does not trigger a destroy and create of the cluster. This is not consistent with the terraform common practices - it should attempt to destroy and recreate. It is up to the user of the provider to decide on the behavior, rather than the provider itself. https://developer.hashicorp.com/terraform/language/meta-arguments/lifecycle#ignore_changes change field exists for this reason.

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Terraform CLI and Terraform IBM Provider Version

Affected Resource(s)

• ibm_container_vpc_cluster

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

resource "ibm_container_vpc_cluster" "cluster" {
  name              = "my_vpc_cluster"
  vpc_id            = "r006-abb7c7ea-aadf-41bd-94c5-b8521736fadf"
  kube_version      = "4.15_openshift"
  flavor            = "bx2.16x64"
  worker_count      = "2"
  entitlement       = "cloud_pak"
  operating_system  = "REDHAT_8_64"
  cos_instance_crn  = ibm_resource_instance.cos_instance.id
  resource_group_id = data.ibm_resource_group.resource_group.id
  zones {
      subnet_id = "0717-0c0899ce-48ac-4eb6-892d-4e2e1ff8c9478"
      name      = "us-south-1"
    }
}

Debug Output

Panic Output

Expected Behavior

Cluster should destroy and create if the value of operating_system is changed

Actual Behavior

No changes identified

Steps to Reproduce

1. terraform apply with operating_system value set to REDHAT_8_64
2. terraform apply with operating_system value now set to RHCOS

Important Factoids

References

• #0000

[hkantare]

@z0za
Can you look into the issue

[z0za]

hey @ocofaigh - it is expected. there has been a change in the behaviour of the cluster resource and now the workerpool related fields only affect the cluster creation.
https://registry.terraform.io/providers/IBM-Cloud/ibm/latest/docs/resources/container_vpc_cluster#operating_system

@attilatabori has written a blog post describing the change:
https://community.ibm.com/community/user/blogs/attila-lszl-tbori/2024/01/22/upcoming-changes-to-ibm-cloud-terraform-provider

after the cluster and default workerpool have been created, the user needs to create a workerpool resource with import_on_create is set to true to be able to manage the default workerpool.
https://github.com/IBM-Cloud/terraform-provider-ibm/blob/master/ibm/service/kubernetes/resource_ibm_container_worker_pool.go#L195
unfortunately the import_on_create flag is missing from the documentation, so we will need to fix it.
[edit] created a PR for this: #5506