Document requirements for running test-kitchen tests

[adrienthebo]

We need to document the requirements/dependencies for running tests with test-kitchen.

For reference, this is my current set of fixtures:

locals {
  project_name = "thebo-gkefixture"
  project_id   = "${local.project_name}-${random_id.project-suffix.hex}"
}

resource "random_id" "project-suffix" {
  byte_length = 2
}

resource "google_project" "main" {
  name            = "${local.project_name}"
  project_id      = "${local.project_id}"
  folder_id       = "${var.folder_id}"
  billing_account = "${var.billing_account}"
}

resource "google_project_services" "main" {
  project  = "${google_project.main.project_id}"
  services = [
    "compute.googleapis.com",
    "bigquery-json.googleapis.com",
    "container.googleapis.com",
    "containerregistry.googleapis.com",
    "oslogin.googleapis.com",
    "pubsub.googleapis.com",
    "storage-api.googleapis.com",
  ]
}

module "network" {
    source = "github.com/terraform-google-modules/terraform-google-network"

    project_id      = "${google_project.main.project_id}"
    network_name    = "vpc-01"
    //shared_vpc_host = "true"

    subnets = [
        {
            subnet_name   = "us-east4-01"
            subnet_ip     = "10.20.16.0/20"
            subnet_region = "us-east4"
        },
    ]

    secondary_ranges = {
        "us-east4-01" = [
            {
                range_name    = "us-east4-01-gke-01-pod"
                ip_cidr_range = "172.18.16.0/20"
            },
            {
                range_name    = "us-east4-01-gke-01-service"
                ip_cidr_range = "172.18.32.0/20"
            },
            {
                range_name    = "us-east4-01-gke-02-pod"
                ip_cidr_range = "172.18.48.0/20"
            },
            {
                range_name    = "us-east4-01-gke-02-service"
                ip_cidr_range = "172.18.64.0/20"
            },
        ]
    }
}

[Jberlinsky]

For posterity, this is related to #20 (comment)

The issue here is that the test case you were running spins up a node pool with 100 machines. From the docs:

The Pod range as determined by the --cluster-ipv4-cidr or --cluster-secondary-range-name flags must be at least large enough to fit (total number of nodes × 256) IP addresses.

So, in this case, 100 * 256 = 25,600 IP addresses required, whereas a /20 CIDR only fits 4,096. You'd need a /14 block.

As to resolution, I'm open to considering this a fixture setup issue (which should be thoroughly documented, to prevent it from happening to others), or to reducing the number of nodes that the test case in question expects to bring up, as 100 nodes is certainly not an average case.

[morgante]

Can we simply document that requirement as the first step?

[Jberlinsky]

@morgante I'm open to that iterative solution, but I think there's a larger conversation to be had here about repeatable testing. As we were talking about, we should probably focus on making sure that nobody has trouble running tests -- I'm of the belief that providing network fixtures is the least-bad way to handle this.

EDIT: Addressing this here: #20 (comment)

[Jberlinsky]

This was covered in #33. Closing.