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typhoon/docs/fedora-coreos/google-cloud.md

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Google Cloud

In this tutorial, we'll create a Kubernetes v1.18.1 cluster on Google Compute Engine with Fedora CoreOS.

We'll declare a Kubernetes cluster using the Typhoon Terraform module. Then apply the changes to create a network, firewall rules, health checks, controller instances, worker managed instance group, load balancers, and TLS assets.

Controller hosts are provisioned to run an etcd-member peer and a kubelet service. Worker hosts run a kubelet service. Controller nodes run kube-apiserver, kube-scheduler, kube-controller-manager, and coredns, while kube-proxy and calico (or flannel) run on every node. A generated kubeconfig provides kubectl access to the cluster.

Requirements

  • Google Cloud Account and Service Account
  • Google Cloud DNS Zone (registered Domain Name or delegated subdomain)
  • Terraform v0.12.6+ and terraform-provider-ct installed locally

Terraform Setup

Install Terraform v0.12.6+ on your system.

$ terraform version
Terraform v0.12.21

Add the terraform-provider-ct plugin binary for your system to ~/.terraform.d/plugins/, noting the final name.

wget https://github.com/poseidon/terraform-provider-ct/releases/download/v0.5.0/terraform-provider-ct-v0.5.0-linux-amd64.tar.gz
tar xzf terraform-provider-ct-v0.5.0-linux-amd64.tar.gz
mv terraform-provider-ct-v0.5.0-linux-amd64/terraform-provider-ct ~/.terraform.d/plugins/terraform-provider-ct_v0.5.0

Read concepts to learn about Terraform, modules, and organizing resources. Change to your infrastructure repository (e.g. infra).

cd infra/clusters

Provider

Login to your Google Console API Manager and select a project, or signup if you don't have an account.

Select "Credentials" and create a service account key. Choose the "Compute Engine Admin" and "DNS Administrator" roles and save the JSON private key to a file that can be referenced in configs.

mv ~/Downloads/project-id-43048204.json ~/.config/google-cloud/terraform.json

Configure the Google Cloud provider to use your service account key, project-id, and region in a providers.tf file.

provider "google" {
  version     = "3.12.0"
  project     = "project-id"
  region      = "us-central1"
  credentials = file("~/.config/google-cloud/terraform.json")
}

provider "ct" {
  version = "0.5.0"
}

Additional configuration options are described in the google provider docs.

!!! tip Regions are listed in docs or with gcloud compute regions list. A project may contain multiple clusters across different regions.

Fedora CoreOS Images

Fedora CoreOS publishes images for Google Cloud, but does not yet upload them. Google Cloud allows custom boot images to be uploaded to a bucket and imported into your project.

Download a Fedora CoreOS GCP gzipped tarball and upload it to a Google Cloud storage bucket.

gsutil list
gsutil cp fedora-coreos-31.20200323.3.2-gcp.x86_64.tar.gz gs://BUCKET

Create a Compute Engine image from the file.

gcloud compute images create fedora-coreos-31-20200323-3-2 --source-uri gs://BUCKET/fedora-coreos-31.20200323.3.2-gcp.x86_64.tar.gz

Cluster

Define a Kubernetes cluster using the module google-cloud/fedora-coreos/kubernetes.

module "yavin" {
  source = "git::https://github.com/poseidon/typhoon//google-cloud/fedora-coreos/kubernetes?ref=development-sha"

  # Google Cloud
  cluster_name  = "yavin"
  region        = "us-central1"
  dns_zone      = "example.com"
  dns_zone_name = "example-zone"

  # custom image name from above
  os_image = "fedora-coreos-31-20200323-3-2"

  # configuration
  ssh_authorized_key = "ssh-rsa AAAAB3Nz..."

  # optional
  worker_count = 2
}

Reference the variables docs or the variables.tf source.

ssh-agent

Initial bootstrapping requires bootstrap.service be started on one controller node. Terraform uses ssh-agent to automate this step. Add your SSH private key to ssh-agent.

ssh-add ~/.ssh/id_rsa
ssh-add -L

Apply

Initialize the config directory if this is the first use with Terraform.

terraform init

Plan the resources to be created.

$ terraform plan
Plan: 64 to add, 0 to change, 0 to destroy.

Apply the changes to create the cluster.

$ terraform apply
module.yavin.null_resource.bootstrap: Still creating... (10s elapsed)
...
module.yavin.null_resource.bootstrap: Still creating... (5m30s elapsed)
module.yavin.null_resource.bootstrap: Still creating... (5m40s elapsed)
module.yavin.null_resource.bootstrap: Creation complete (ID: 5768638456220583358)

Apply complete! Resources: 62 added, 0 changed, 0 destroyed.

In 4-8 minutes, the Kubernetes cluster will be ready.

Verify

Install kubectl on your system. Obtain the generated cluster kubeconfig from module outputs (e.g. write to a local file).

resource "local_file" "kubeconfig-yavin" {
  content  = module.yavin.kubeconfig-admin
  filename = "/home/user/.kube/configs/yavin-config"
}

List nodes in the cluster.

$ export KUBECONFIG=/home/user/.kube/configs/yavin-config
$ kubectl get nodes
NAME                                       ROLES    STATUS  AGE  VERSION
yavin-controller-0.c.example-com.internal  <none>   Ready   6m   v1.18.1
yavin-worker-jrbf.c.example-com.internal   <none>   Ready   5m   v1.18.1
yavin-worker-mzdm.c.example-com.internal   <none>   Ready   5m   v1.18.1

List the pods.

$ kubectl get pods --all-namespaces
NAMESPACE     NAME                                      READY  STATUS    RESTARTS  AGE
kube-system   calico-node-1cs8z                         2/2    Running   0         6m
kube-system   calico-node-d1l5b                         2/2    Running   0         6m
kube-system   calico-node-sp9ps                         2/2    Running   0         6m
kube-system   coredns-1187388186-dkh3o                  1/1    Running   0         6m
kube-system   coredns-1187388186-zj5dl                  1/1    Running   0         6m
kube-system   kube-apiserver-controller-0               1/1    Running   0         6m
kube-system   kube-controller-manager-controller-0      1/1    Running   0         6m
kube-system   kube-proxy-117v6                          1/1    Running   0         6m
kube-system   kube-proxy-9886n                          1/1    Running   0         6m
kube-system   kube-proxy-njn47                          1/1    Running   0         6m
kube-system   kube-scheduler-controller-0               1/1    Running   0         6m

Going Further

Learn about maintenance and addons.

Variables

Check the variables.tf source.

Required

Name Description Example
cluster_name Unique cluster name (prepended to dns_zone) "yavin"
region Google Cloud region "us-central1"
dns_zone Google Cloud DNS zone "google-cloud.example.com"
dns_zone_name Google Cloud DNS zone name "example-zone"
os_image Fedora CoreOS image for compute instances "fedora-coreos-31-20200323-3-2"
ssh_authorized_key SSH public key for user 'core' "ssh-rsa AAAAB3NZ..."

Check the list of valid regions and list Fedora CoreOS images with gcloud compute images list | grep fedora-coreos.

DNS Zone

Clusters create a DNS A record ${cluster_name}.${dns_zone} to resolve a TCP proxy load balancer backed by controller instances. This FQDN is used by workers and kubectl to access the apiserver(s). In this example, the cluster's apiserver would be accessible at yavin.google-cloud.example.com.

You'll need a registered domain name or delegated subdomain on Google Cloud DNS. You can set this up once and create many clusters with unique names.

resource "google_dns_managed_zone" "zone-for-clusters" {
  dns_name    = "google-cloud.example.com."
  name        = "example-zone"
  description = "Production DNS zone"
}

!!! tip "" If you have an existing domain name with a zone file elsewhere, just delegate a subdomain that can be managed on Google Cloud (e.g. google-cloud.mydomain.com) and update nameservers.

Optional

Name Description Default Example
controller_count Number of controllers (i.e. masters) 1 3
worker_count Number of workers 1 3
controller_type Machine type for controllers "n1-standard-1" See below
worker_type Machine type for workers "n1-standard-1" See below
disk_size Size of the disk in GB 40 100
worker_preemptible If enabled, Compute Engine will terminate workers randomly within 24 hours false true
controller_snippets Controller Fedora CoreOS Config snippets [] examples
worker_snippets Worker Fedora CoreOS Config snippets [] examples
networking Choice of networking provider "calico" "calico" or "flannel"
pod_cidr CIDR IPv4 range to assign to Kubernetes pods "10.2.0.0/16" "10.22.0.0/16"
service_cidr CIDR IPv4 range to assign to Kubernetes services "10.3.0.0/16" "10.3.0.0/24"
worker_node_labels List of initial worker node labels [] ["worker-pool=default"]

Check the list of valid machine types.

Preemption

Add worker_preemptible = "true" to allow worker nodes to be preempted at random, but pay significantly less. Clusters tolerate stopping instances fairly well (reschedules pods, but cannot drain) and preemption provides a nice reward for running fault-tolerant cluster systems.`