GCP GitLab Runner

A Terraform module for configuring a GCP-based GitLab CI Runner.

This runner is configured to use the docker+machine executor which allows the infrastructure to be scaled up and down as demand requires. The minimum cost (during zero activity) is the cost of an f1-micro instance.

The long-running runner instance runs under a gitlab-ci-runner service account. This account will be granted all required permissions to spawn worker instances on demand.

The worker instances run under a gitlab-ci-worker service account. This account will need to be granted any privileges required to perform build and deploy activities. For example, the storage.admin role can be granted to the worker account as follows:

Usage

To use this module you can create a main.tf file similar to the following example. Note that you will need to modify the roles assigned to the CI worker service account based on your specific project needs.

# Configure GCP provider
provider "google" {
  version = "~> 2.13"
  project = var.gcp_project
  region  = var.gcp_region
}

# Install the GitLab CI Runner infrastructure
module "ci" {
  source      = "digio/gitlab-runner/google"
  version     = "0.0.11"

  gcp_project = var.gcp_project
  gcp_zone    = var.gcp_zone
  gitlab_url  = var.gitlab_url
  ci_token    = var.ci_token
}

# Grant the storage.admin role to the CI workers.  Add other roles as required.
resource "google_project_iam_member" "worker_storage_admin" {
  role   = "roles/storage.admin"
  member = "serviceAccount:${module.ci.ci_worker_service_account.email}"
}

Then perform the following commands:

• terraform init to get the plugins
• terraform plan to see the infrastructure plan
• terraform apply to apply the infrastructure build
• terraform destroy to destroy the built infrastructure