Creating Clusters

We used minikube for learning. But how are real clusters made? There are two main roads. Build it yourself with kube admin, on machines you control. Or let a cloud provider run the control plane for you, which is the choice of most teams. In this lesson, you will compare both roads.

• Build it yourself
• Or let the cloud run it
• Choose by your needs

Building with kubeadm

Kube admin is the official tool for building a cluster by hand. On the first machine, one command initialises the control plane, and prints a join command. Then you install a network plugin. On each worker, you run the join command, with the token it printed. Later, the same tool plans and applies upgrades, one minor version at a time. You are responsible for everything, the machines, the backups, and the certificates, which is powerful, but demanding.

# on the first control plane machine
kubeadm init --pod-network-cidr=10.244.0.0/16

# install a network plugin, then on each worker:
kubeadm join 10.0.0.10:6443 --token <token> \
  --discovery-token-ca-cert-hash sha256:<hash>

# upgrade later, one minor version at a time
kubeadm upgrade plan
kubeadm upgrade apply v1.35.0

Self-managed or managed

A managed service, like E K S, G K E, or A K S, runs the control plane for you. The provider keeps et see dee backed up, patches it, and upgrades it with a click. You only manage worker nodes, or even not those, with the serverless options. The price is less control, and a monthly fee. A self managed cluster gives total control and flexibility, and it suits special hardware, or data centers, but needs a skilled team. For most companies, managed is the sensible default.

Summary