Autoscaling in combination with node_count for google_container_cluster

[wmuizelaar]

Hi there,

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Terraform Version

$terraform -v
Terraform v0.11.1
+ provider.google v1.4.0
+ provider.local v1.0.0

Affected Resource(s)

Please list the resources as a list, for example:

• google_container_cluster

Terraform Configuration Files

resource "google_container_cluster" "bolcom-sbf3pp" {
  name               = "bolcom-sbf3pp"
  zone               = "europe-west1-c"
  project            = "bolcom-frieps"
  min_master_version = "1.8.4-gke.0"
  enable_legacy_abac = false
  network            = "sbf3pp-network"
  subnetwork         = "bolcom-sbf3pp-subnetwork"


  master_auth {
    username =""
    password =""
  }

  addons_config {
    http_load_balancing {
      disabled = false
    }
    horizontal_pod_autoscaling {
      disabled = true
    }
    kubernetes_dashboard {
      disabled = true
    }
  }

  maintenance_policy {
    daily_maintenance_window {
      start_time = "02:00"
    }
  }

  ip_allocation_policy {
    cluster_secondary_range_name = "bolcom-sbf3pp-pods"
    services_secondary_range_name = "bolcom-sbf3pp-services"
  }

  master_authorized_networks_config {
    cidr_blocks = [
      { cidr_block = "91.195.1.40/30", display_name = "office" },
      { cidr_block = "185.14.171.68/32", display_name = "shd-gcp-jump-001" },
    ]
  }

  lifecycle {
    ignore_changes = [ "node_count" ]
  }
  node_pool {
    name       = "default-pool"
    node_count = 1

    autoscaling {
      min_node_count = 1
      max_node_count = 3
    }
    node_config {
      preemptible = false
      disk_size_gb = 100
      machine_type = "n1-standard-1"
      oauth_scopes = [
              "https://www.googleapis.com/auth/compute",
        "https://www.googleapis.com/auth/devstorage.read_only",
        "https://www.googleapis.com/auth/logging.write",
        "https://www.googleapis.com/auth/monitoring",
      ]

      tags = ["bolcom-sbf3pp-default-pool"]
    }
  }
}

Debug Output

See https://gist.github.com/wmuizelaar/b32116014ac72767b9dd26e6e585b5e1

Expected Behavior

Nothing should have happened, since the node_count change should be ignore due to the lifecycle configuration.

Actual Behavior

The nodecount was changed, and therefore the current node-count will be decreased to 1 again.

Steps to Reproduce

1. terraform apply
2. Scale the cluster up to 3 nodes (via the Google GUI, for example, or by scheduling enough pods on the cluster so that autoscaling will kick in
3. terraform apply again. The

Important Factoids

I would think that the initial_node_count could be used to 'fix' this issue, but that option is deprecated. So maybe I'm doing things wrong, but if I create a cluster without the node_count parameter, the cluster-size gets set to '0', and auto-scaling doesn't scale it up to '1'.

[wmuizelaar]

Confirmation that using 'initital_node_count' fixes the issue, but since that one is deprecated, I would like some advice on how to setup this config :-)

[danawillow]

Question- if you set autoscaling but not node_count, what would you expect to happen? It seems like we have two options:

• Un-deprecate initial_node_count
• Allow not setting initial_node_count or node_count if autoscaling is set (and then set the initial node count to min_node_count)

I like the second one so that users don't have to worry about whether they set initial_node_count or node_count for their node pools (in case they add autoscaling later, for example), but I also only want to do that if it doesn't lead to unexpected behavior.

[wmuizelaar]

I like the second one best as well.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. If you feel I made an error 🤖 🙉 , please reach out to my human friends 👉 [email protected]. Thanks!