242 lines
10 KiB
Markdown
242 lines
10 KiB
Markdown
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# Google Cloud
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In this tutorial, we'll create a Kubernetes v1.7.3 cluster on Google Compute Engine (not GKE).
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We'll declare a Kubernetes cluster in Terraform using the Typhoon Terraform module. On apply, a network, firewall rules, managed instance groups of Kubernetes controllers and workers, network load balancers for controllers and workers, and health checks will be created.
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Controllers and workers are provisioned to run a `kubelet`. A one-time [bootkube](https://github.com/kubernetes-incubator/bootkube) bootstrap schedules `etcd`, `apiserver`, `scheduler`, `controller-manager`, and `kube-dns` on controllers and runs `kube-proxy` and `flannel` on each node. A generated `kubeconfig` provides `kubectl` access to the cluster.
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## Requirements
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* Google Cloud Account and Service Account
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* Google Cloud DNS Zone (registered Domain Name or delegated subdomain)
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* Terraform v0.9.2+ and [terraform-provider-ct](https://github.com/coreos/terraform-provider-ct) installed locally
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## Terraform Setup
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Install [Terraform](https://www.terraform.io/downloads.html) v0.9.2+ on your system.
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```sh
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$ terraform version
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Terraform v0.10.1
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```
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Add the [terraform-provider-ct](https://github.com/coreos/terraform-provider-ct) plugin binary for your system.
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```sh
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wget https://github.com/coreos/terraform-provider-ct/releases/download/v0.2.0/terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
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tar xzf terraform-provider-ct-v0.2.0-linux-amd64.tar.gz
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sudo mv terraform-provider-ct-v0.2.0-linux-amd64/terraform-provider-ct /usr/local/bin/
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```
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Add the plugin to your `~/.terraformrc`.
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```
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providers {
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ct = "/usr/local/bin/terraform-provider-ct"
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}
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```
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Read [concepts](concepts.md) to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. `infra`).
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```
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cd infra/clusters
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```
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## Provider
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Login to your Google Console [API Manager](https://console.cloud.google.com/apis/dashboard) and select a project, or [signup](https://cloud.google.com/free/) if you don't have an account.
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Select "Credentials", and create service account key credentials. Choose the "Compute Engine default service account" and save the JSON private key to a file that can be referenced in configs.
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```sh
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mv ~/Downloads/project-id-43048204.json ~/.config/google-cloud/terraform.json
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```
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Configure the Google Cloud provider to use your service account key, project-id, and region in a `providers.tf` file.
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```tf
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provider "google" {
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credentials = "${file("~/.config/google-cloud/terraform.json")}"
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project = "project-id"
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region = "us-central1"
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}
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```
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Additional configuration options are described in the `google` provider [docs](https://www.terraform.io/docs/providers/google/index.html).
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!!! tip
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A project may contain multiple clusters if you wish. Regions are listed in [docs](https://cloud.google.com/compute/docs/regions-zones/regions-zones) or with `gcloud compute regions list`.
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## Cluster
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Define a Kubernetes cluster using the module `google-cloud/container-linux/kubernetes`.
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```tf
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module "google-cloud-yavin" {
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source = "git::https://github.com/poseidon/typhoon//google-cloud/container-linux/kubernetes"
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# Google Cloud
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zone = "us-central1-c"
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dns_zone = "example.com"
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dns_zone_name = "example-zone"
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os_image = "coreos-stable-1465-6-0-v20170817"
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cluster_name = "yavin"
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controller_count = 1
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worker_count = 2
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ssh_authorized_key = "ssh-rsa AAAAB3Nz..."
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# output assets dir
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asset_dir = "/home/user/.secrets/clusters/yavin"
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}
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```
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Reference the [variables docs](#variables) or the [variables.tf](https://github.com/poseidon/typhoon/blob/master/google-cloud/container-linux/kubernetes/variables.tf) source.
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## ssh-agent
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Initial bootstrapping requires `bootkube.service` be started on one controller node. Terraform uses `ssh-agent` to automate this step. Add your SSH private key to `ssh-agent`.
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```sh
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ssh-add ~/.ssh/id_rsa
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ssh-add -L
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```
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!!! warning
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`terrafrom apply` will hang connecting to a controller if `ssh-agent` does not contain the SSH key.
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## Apply
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Initialize the config directory if this is the first use with Terraform.
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```sh
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terraform init
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```
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Get or update Terraform modules.
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```sh
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$ terraform get # downloads missing modules
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$ terraform get --update # updates all modules
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Get: git::https://github.com/poseidon/typhoon (update)
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Get: git::https://github.com/poseidon/bootkube-terraform.git?ref=v0.6.1 (update)
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```
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Plan the resources to be created.
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```sh
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$ terraform plan
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Plan: 64 to add, 0 to change, 0 to destroy.
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```
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Apply the changes to create the cluster.
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```sh
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$ terraform apply
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module.google-cloud-yavin.null_resource.bootkube-start: Still creating... (10s elapsed)
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...
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module.google-cloud-yavin.null_resource.bootkube-start: Still creating... (8m30s elapsed)
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module.google-cloud-yavin.null_resource.bootkube-start: Still creating... (8m40s elapsed)
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module.google-cloud-yavin.null_resource.bootkube-start: Creation complete (ID: 5768638456220583358)
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Apply complete! Resources: 64 added, 0 changed, 0 destroyed.
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```
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In 5-10 minutes, the Kubernetes cluster will be ready.
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## Verify
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[Install kubectl](https://coreos.com/kubernetes/docs/latest/configure-kubectl.html) on your system. Use the generated `kubeconfig` credentials to access the Kubernetes cluster and list nodes.
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```
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$ KUBECONFIG=/home/user/.secrets/clusters/yavin/auth/kubeconfig
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$ kubectl get nodes
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NAME STATUS AGE VERSION
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yavin-controller-1682.c.example-com.internal Ready 6m v1.7.3+coreos.0
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yavin-worker-jrbf.c.example-com.internal Ready 5m v1.7.3+coreos.0
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yavin-worker-mzdm.c.example-com.internal Ready 5m v1.7.3+coreos.0
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```
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List the pods.
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```
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$ kubectl get pods --all-namespaces
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NAMESPACE NAME READY STATUS RESTARTS AGE
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kube-system etcd-operator-3329263108-f443m 1/1 Running 1 6m
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kube-system kube-apiserver-zppls 1/1 Running 0 6m
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kube-system kube-controller-manager-3271970485-gh9kt 1/1 Running 0 6m
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kube-system kube-controller-manager-3271970485-h90v8 1/1 Running 1 6m
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kube-system kube-dns-1187388186-zj5dl 3/3 Running 0 6m
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kube-system kube-etcd-0000 1/1 Running 0 5m
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kube-system kube-etcd-network-checkpointer-crznb 1/1 Running 0 6m
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kube-system kube-flannel-1cs8z 2/2 Running 0 6m
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kube-system kube-flannel-d1l5b 2/2 Running 0 6m
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kube-system kube-flannel-sp9ps 2/2 Running 0 6m
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kube-system kube-proxy-117v6 1/1 Running 0 6m
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kube-system kube-proxy-9886n 1/1 Running 0 6m
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kube-system kube-proxy-njn47 1/1 Running 0 6m
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kube-system kube-scheduler-3895335239-5x87r 1/1 Running 0 6m
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kube-system kube-scheduler-3895335239-bzrrt 1/1 Running 1 6m
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kube-system pod-checkpointer-l6lrt 1/1 Running 0 6m
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```
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## Going Further
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Learn about [version pinning](concepts.md#versioning), maintenance, and [addons](addons.md).
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!!! note
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On Container Linux clusters, install the `container-linux-update-operator` addon to coordinate reboots and drains when nodes auto-update. Otherwise, updates may not be applied until the next reboot.
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## Variables
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### Required
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| Name | Description | Example |
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| cluster_name | Unique cluster name (prepended to dns_zone) | "yavin" |
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| zone | Google Cloud zone | "us-central1-f" |
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| dns_zone | Google Cloud DNS zone | "google-cloud.example.com" |
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| dns_zone_name | Google Cloud DNS zone name | "example-zone" |
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| ssh_authorized_key | SSH public key for ~/.ssh_authorized_keys | "ssh-rsa AAAAB3NZ..." |
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| os_image | OS image for compute instances | "coreos-stable-1465-6-0-v20170817" |
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| asset_dir | Path to a directory where generated assets should be placed (contains secrets) | "/home/user/.secrets/clusters/yavin" |
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Check the list of valid [zones](https://cloud.google.com/compute/docs/regions-zones/regions-zones) and list Container Linux [images](https://cloud.google.com/compute/docs/images) with `gcloud compute images list | grep coreos`.
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#### DNS Zone
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Clusters create a DNS A record `${cluster_name}.${dns_zone}` to resolve a network load balancer backed by controller instances. This FQDN is used by workers and `kubectl` to access the apiserver. In this example, the cluster's apiserver would be accessible at `yavin.google-cloud.example.com`.
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You'll need a registered domain name or subdomain registered in a Google Cloud DNS zone. You can set this up once and create many clusters with unqiue names.
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```tf
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resource "google_dns_managed_zone" "zone-for-clusters" {
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dns_name = "google-cloud.example.com."
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name = "example-zone"
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description = "Production DNS zone"
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}
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```
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!!! tip ""
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If you have an existing domain name with a zone file elsewhere, just carve out a subdomain that can be managed on Google Cloud (e.g. google-cloud.mydomain.com) and [update nameservers](https://cloud.google.com/dns/update-name-servers).
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### Optional
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| Name | Description | Default | Example |
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| machine_type | Machine type for compute instances | "n1-standard-1" | See below |
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| controller_count | Number of controllers (i.e. masters) | 1 | 1 |
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| worker_count | Number of workers | 1 | 3 |
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| worker_preemptible | If enabled, Compute Engine will terminate controllers randomly within 24 hours | false | true |
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| pod_cidr | CIDR range to assign to Kubernetes pods | "10.2.0.0/16" | "10.22.0.0/16" |
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| service_cidr | CIDR range to assgin to Kubernetes services | "10.3.0.0/16" | "10.3.0.0/24" |
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Check the list of valid [machine types](https://cloud.google.com/compute/docs/machine-types).
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#### Preemption
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Add `worker_premeptible = "true"` to allow worker nodes to be [preempted](https://cloud.google.com/compute/docs/instances/preemptible) at random, but pay [significantly](https://cloud.google.com/compute/pricing) less. Clusters tolerate stopping instances fairly well (reschedules pods, but cannot drain) and preemption provides a nice reward for running fault-tolerant cluster systems.`
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