google_compute_autoscaler update error

[natedogith1]

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Terraform Version & Provider Version(s)

Terraform v1.3.9
on linux_amd64

• provider registry.terraform.io/hashicorp/google v4.84.0
• provider registry.terraform.io/hashicorp/google-beta v4.84.0

Affected Resource(s)

google_compute_autoscaler

Terraform Configuration

resource "google_compute_autoscaler" "default" {
  provider    = google-beta
  project     = var.project_id
  name        = format("scal-%s",var.name)
  description = "Terraform-managed."
  zone        = var.zone
  target      = google_compute_instance_group_manager.default.id

  autoscaling_policy {
    max_replicas    = 10
    min_replicas    = 2
    cooldown_period = 900
    mode            = "ON"

    cpu_utilization {
      target = 0.99
    }
  }
  lifecycle {
    ignore_changes        = [ autoscaling_policy ]
  }
}


resource "google_compute_instance_group_manager" "default" {
  provider           = google-beta
  project            = var.project_id
  zone               = var.zone
  name               = format("mig-%s",var.name)
  description        = "Terraform-managed."
  base_instance_name = format("mig-%s",var.name)
  target_pools       = []
  wait_for_instances = false
  wait_for_instances_status = "STABLE"
  named_port {
    name = "https-443"
    port = 443
  }
  named_port {
    name = "https-8443"
    port = 8443
  }
  version {
    instance_template = var.default_version.instance_template
    name              = var.default_version.name
  }
  lifecycle {
    create_before_destroy = true
    ignore_changes        = [ version, update_policy, auto_healing_policies, ]
  }

  timeouts {
    create = "5m"
    update = "5m"
    delete = "15m"
  }
}

Debug Output

Terraform will perform the following actions:
  # google_compute_autoscaler.default will be updated in-place
  ~ resource "google_compute_autoscaler" "default" {
      + description        = "Terraform-managed."
        id                 = <content removed>
        name               = <content removed>
        # (5 unchanged attributes hidden)
        # (1 unchanged block hidden)
    }

╷
│ Error: Error waiting for Updating Autoscaler: Required field 'resource.autoscalingPolicy.maxNumReplicas' not specified
│ 
│ 
│   with google_compute_autoscaler.default[0],
│   on main.tf line 37, in resource "google_compute_autoscaler" "default":
│   37: resource "google_compute_autoscaler" "default" {
│ 
╵

Expected Behavior

Apply perform successfully

Actual Behavior

Apply fails with message "Required field 'resource.autoscalingPolicy.maxNumReplicas' not specified"

Steps to reproduce

1. terraform apply
2. Change min and max number of instances in GCP console to 0. (this also happens to clear the autoscaler description)
3. terraform apply

Important Factoids

life_cycle is set to ignore autoscaling_policy changes. I have not tested if setting the min and max replica numbers to 0 in the terraform directly also causes this problem.

References

No response

b/345321691

[ggtisc]

Confirmed issue!

As user explains when max_replicas and min_replicas values are equal to 0 terraform returns the next error message:

╷

│ Error: Error waiting for Updating Autoscaler: Required field 'resource.autoscalingPolicy.maxNumReplicas' not specified
│ 
│   with google_compute_autoscaler.default[0],
│   on main.tf line 37, in resource "google_compute_autoscaler" "default":
│   37: resource "google_compute_autoscaler" "default" {

This could be an inconsistency, since both terraform registry and Google Cloud documentation is not specified that the value cannot be 0

[github-actions]

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