node_pools_cgroup_mode var does not correctly handle the "all" map key

[bboerst]

TL;DR

For module users who want to pin the CGROUP version using the new node_pools_cgroup_mode feature released in #2001, specifying an "all" key does not correctly apply the value to all node-pools like expected.

Some examples...

This does not apply the change to any node pools.

node_pools_cgroup_mode = {
  all = "CGROUP_MODE_V2"
}

...but specifying the individual node pool names does work:

node_pools_cgroup_mode = {
  default-pool = "CGROUP_MODE_V2"
  ondemand = "CGROUP_MODE_V2"
  spot = "CGROUP_MODE_V2"
}

I believe that the logic for handling all is missing from here:

terraform-google-kubernetes-engine/modules/beta-private-cluster/cluster.tf

Line 880 in ef6c1ba

cgroup_mode = local.node_pools_cgroup_mode[each.value["name"]] == "" ? null : local.node_pools_cgroup_mode[each.value["name"]]

Expected behavior

The all key is nice for users who want to pin the CGROUP version for all node-pools without needing to specify each individual node-pool.

The default variable does include an all key, so I believe that the intention is to have this working:

terraform-google-kubernetes-engine/modules/beta-private-cluster/variables.tf

Lines 243 to 246 in ef6c1ba

	default = {
	all = ""
	default-node-pool = ""
	}

Observed behavior

When specifying all for node_pools_cgroup_mode, no changes are made to the cluster configuration. When each individual node-pool is specified, then changes are made correctly.

Terraform Configuration

node_pools_cgroup_mode = {
  all = "CGROUP_MODE_V2"
}

Terraform Version

1.9.8

Additional information

No response