GKE permadiff/thrashing when update_settings values are updating

[rileykarson]

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Terraform Version

$ terraform -v
Terraform v1.3.2
on darwin_arm64
+ provider registry.terraform.io/hashicorp/google v4.44.1

I believe the bug to have been introduced in 4.44.0, by hashicorp/terraform-provider-google-beta#4860

Affected Resource(s)

• google_container_cluster

Terraform Configuration Files

provider "google" {
  version = "~> 4.44.1"
}

resource "google_container_cluster" "cluster" {
  name               = "my-surge"
  location           = "us-central1-a"
  initial_node_count = 3
}

resource "google_container_node_pool" "np1" {
  name               = "my-surge"
  location           = "us-central1-a"
  cluster            = google_container_cluster.cluster.name
  initial_node_count = 2
  upgrade_settings {
    max_surge = 2
-    max_unavailable = 1
+    max_unavailable = 2
  }
}

Debug Output

---[ REQUEST ]---------------------------------------
PUT /v1/projects/my-project/locations/us-central1-a/clusters/my-surge/nodePools/my-surge?alt=json&prettyPrint=false HTTP/1.1
Host: container.googleapis.com
User-Agent: google-api-go-client/0.5 Terraform/1.3.2 (+https://www.terraform.io) Terraform-Plugin-SDK/2.10.1 terraform-provider-google/dev
Content-Length: 60
Content-Type: application/json
X-Goog-Api-Client: gl-go/1.18.1 gdcl/0.102.0
Accept-Encoding: gzip

{
 "upgradeSettings": {
  "maxUnavailable": 2,
  "strategy": "SURGE"
 }
}

Panic Output

N/A

Expected Behavior

My cluster should update max_unavailable while preserving max_surge

Actual Behavior

max_surge was set to zero, and a diff was published

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # google_container_node_pool.np1 will be updated in-place
  ~ resource "google_container_node_pool" "np1" {
        id                          = "projects/graphite-test-rileykarson/locations/us-central1-a/clusters/my-surge/nodePools/my-surge"
        name                        = "my-surge"
        # (9 unchanged attributes hidden)

      ~ upgrade_settings {
          ~ max_surge       = 0 -> 2
            # (2 unchanged attributes hidden)
        }

        # (2 unchanged blocks hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Steps to Reproduce

Using the configuration above:

1. terraform apply with max_available equal to 1
2. terraform apply with max_available equal to 2
3. Keep running terraform apply over and over again

Important Factoids

References

• Add blue green upgrade settings. terraform-provider-google-beta#4860

[github-actions]

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