Add a new Google Cloud cluster

This guide will walk through the process of adding a new cluster to our terraform configuration.

Cluster Design

This guide will assume you have already followed the guidance in Cluster design considerations to select the appropriate infrastructure.

Creating a Terraform variables file for the cluster

The first step is to create a .tfvars file in the terraform/gcp/projects directory. Give it a descriptive name that at a glance provides context to the location and/or purpose of the cluster.

The minimum inputs this file requires are:

  • prefix: Prefix for all objects created by terraform. Primary identifier to ‘group’ together resources.

  • project_id: GCP Project ID to create resources in. Should be the id, rather than display name of the project.

See the variables file for other inputs this file can take and their descriptions.

Example .tfvars file:

prefix     = "my-awesome-project"
project_id = "my-awesome-project-id

Once you have created this file, open a Pull Request to the infrastructure repo for review.

Initialising Terraform

Our default terraform state is located centrally in our two-eye-two-see-org GCP project, therefore you must authenticate gcloud to your account before initialising terraform.

gcloud auth application-default login

Then you can change into the terraform directory and initialise

cd terraform/gcp
terraform init -backend-config=backends/default-backend.hcl -reconfigure


If you are working on a project which you cannot access with your 2i2c account, there are other backend config files stored in terraform/backends that will configure a different storage bucket to read/write the remote terraform state. This saves us the pain of having to handle multiple authentications as these storage buckets are within the project we are trying to deploy to.

For example, to work with Pangeo you would initialise terraform like so:

terraform init -backend-config=pangeo-backend.hcl -reconfigure

Creating a new terraform workspace

We use terraform workspaces so that the state of one .tfvars file does not influence another. Create a new workspace with the below command, and again give it the same name as the .tfvars filename.

terraform workspace new WORKSPACE_NAME


Workspaces are defined per backend. If you can’t find the workspace you’re looking for, double check you’ve enabled the correct backend.

Plan and Apply Changes


Make sure the Artifact Registry API in enabled on the project before deploying!

Plan your changes with the terraform plan command, passing the .tfvars file as a variable file.

terraform plan -var-file=projects/CLUSTER.tfvars

Check over the output of this command to ensure nothing if being created/deleted than you expected. Copy-paste the plan into your open Pull Request so a fellow 2i2c engineer can double check it too.

If you’re both satisfied with the plan, merge the Pull Request and apply the changes to deploy the cluster.

terraform apply -var-file=projects/CLUSTER.tfvars

Congratulations, you’ve just deployed a new cluster!

Exporting and Encrypting the Continuous Deployment Service Account

To begin deploying and operating hubs on your new cluster, we need to export the Continuous Deployment Service Account created by terraform, encrypt it using sops, and store it in the secrets directory of the infrastructure repo.

Check you are still in the correct terraform workspace

terraform workspace show

If you need to change, you can do so as follows

terraform workspace list  # List all available workspaces
terraform workspace select WORKSPACE_NAME

Then, output the JSON key for the service account created by terraform to a file under the secrets directory.

terraform output -raw ci_deployer_key > ../../secrets/CLUSTER_NAME.json

where CLUSTER_NAME matches the name of our .tfvars file.

Encrypt the key using sops


You must be logged into Google with your account at this point so sops can read the encryption key from the two-eye-two-see project.

cd ..
sops --encrypt --in-place secrets/CLUSTER_NAME.json

This key can now be committed to the infrastructure repo and used to deploy and manage hubs hosted on that cluster.