container.training/slides/terraform/quickstart-gke.md

GKE quick start

• Install Terraform and GCP SDK (gcloud)

• Authenticate with gcloud auth login

  (this is to use gcloud CLI commands)

• Authenticate with gcloud auth application-default login

  (this is so that Terraform can use the GCP API)

---

Create project

• Create a project or use one of your existing ones

• Set the GOOGLE_PROJECT env var to the project name

  (this will be used by Terraform)

Note 1: there must be a billing account linked to the project.

Note 2: if the required APIs are not enabled on the project, we will get error messages telling us "please enable that API" when using the APIs for the first time. The error messages should include instructions to do this one-time process.

---

Create configuration

• Create empty directory

• Create a bunch of .tf files as shown in next slides

  (feel free to adjust the values!)

---

Configuring providers

• We'll use the google provider

• It's an official provider (maintained by hashicorp)

• Which means that we don't have to add it explicitly to our configuration

  (terraform init will take care of it automatically)

• That'll simplify a tiny bit our "getting started" experience!

---

cluster.tf

resource "google_container_cluster" "mycluster" {
  name = "klstr"
  location = "europe-north1-a"
  initial_node_count = 2
}

• google_container_cluster is the type of the resource

• mycluster is the internal Terraform name for that resource

  (useful if we have multiple resources of that type)

• location can be a zone or a region (see next slides for details)

• don't forget initial_node_count otherwise we get a zero-node cluster 🙃

---

Regional vs Zonal vs Multi-Zonal

• If location is a zone, we get a "zonal" cluster

  (control plane and nodes are in a single zone)

• If location is a region, we get a "regional" cluster

  (control plane and nodes span all zones in this region)

• In a region with Z zones, if we say we want N nodes...

  ...we get Z×N nodes

• We can also set location to be a zone, and set additional node_locations

• In that case we get a "multi-zonal" cluster with control plane in a single zone

---

Standard vs Autopilot

• Standard clusters:

  • we manage nodes, node pools, etc.

  • we pay for control plane + nodes

• Autopilot clusters:

  • GKE manages nodes and node pools automatically

  • we cannot add/remove/change/SSH into nodes

  • all pods are in the "guaranteed" QoS class

  • we pay for the resources requested by the pods

---

Create the cluster

• Initialize providers

  terraform init
  

• Create the cluster:

  terraform apply
  

• We'll explain later what that "plan" thing is; just approve it for now!

• Check what happens if we run terraform apply again

• Problems? Check next slide for suggestions...

---

Potential issues

Unknown token: 18:16 IDENT google_compute_network._.name

This seems to happen with older versions of Terraform (pre-1.0).
Upgrade to a recent version. Use tfenv if you need to switch between versions.

Error: google_container_cluster.mycluster: : invalid or unknown key: networking_mode

This seems to happen with older versions of the hashicorp/google provider.
We'll show on next slide how to get a newer version.

---

Pinning provider versions

To upgrade the hashicorp/google provider, add this to the configuration:

terraform {
  required_providers {
    google = {
      source  = "hashicorp/google"
      version = "4.6.0"
    }
  }
}

Then run terraform init -upgrade, then try terraform apply again.

---

Now what?

• Let's connect to the cluster

• Get the credentials for the cluster:

  gcloud container clusters get-credentials klstr --zone=europe-north1
  

  (Adjust the zone if you changed it earlier!)

• This will add the cluster to our kubeconfig file

• Deploy a simple app to the cluster

🎉