kubeadm: Single Node Kubernetes Cluster

This tutorial will walk you through bootstrapping a single-node Kubernetes cluster on Google Compute Engine using kubeadm.

Tutorial

Create a single compute instance:

gcloud compute instances create kubeadm-single-node-cluster \
  --can-ip-forward \
  --image-family ubuntu-1704 \
  --image-project ubuntu-os-cloud \
  --machine-type n1-standard-4 \
  --metadata kubernetes-version=stable-1.8 \
  --metadata-from-file startup-script=startup.sh \
  --tags kubeadm-single-node-cluster \
  --scopes cloud-platform,logging-write

Enable secure remote access to the Kubernetes API server:

gcloud compute firewall-rules create default-allow-kubeadm-single-node-cluster \
  --allow tcp:6443 \
  --target-tags kubeadm-single-node-cluster \
  --source-ranges 0.0.0.0/0

Fetch the client kubernetes configuration file:

gcloud compute scp kubeadm-single-node-cluster:/etc/kubernetes/admin.conf \
  kubeadm-single-node-cluster.conf

It may take a few minutes for the cluster to finish bootstrapping and the client config to become readable.

Set the KUBECONFIG env var to point to the kubeadm-single-node-cluster.conf kubeconfig:

export KUBECONFIG=$(PWD)/kubeadm-single-node-cluster.conf

Set the kubeadm-single-node-cluster kubeconfig server address to the public IP address:

kubectl config set-cluster kubernetes \
  --kubeconfig kubeadm-single-node-cluster.conf \
  --server https://$(gcloud compute instances describe kubeadm-single-node-cluster \
     --format='value(networkInterfaces.accessConfigs[0].natIP)'):6443

Verification

List the Kubernetes nodes:

kubectl get nodes

NAME                          STATUS    ROLES     AGE       VERSION
kubeadm-single-node-cluster   Ready     master    35m       v1.8.0

The node version reflects the kubelet version, therefore it might be different than the kubernetes-version specified above.

Find out Kubernetes API server version:

kubectl version --short

Client Version: v1.8.0
Server Version: v1.8.0

Create a nginx deployment:

kubectl run nginx --image nginx:1.13 --port 80

Expose the nginx deployment:

kubectl expose deployment nginx --type LoadBalancer

Cleanup

gcloud compute instances delete kubeadm-single-node-cluster

gcloud compute firewall-rules delete default-allow-kubeadm-single-node-cluster

rm kubeadm-single-node-cluster.conf