Kubernetes Clusters with kubeadm

Kubeadm Requirements

Updated requirements available here

• A compatible Linux host. The Kubernetes project provides generic instructions for Linux distributions based on Debian and Red Hat, and those distributions without a package manager.
• 2 GB or more of RAM per machine (any less will leave little room for your apps).
• 2 CPUs or more.
• Full network connectivity between all machines in the cluster (public or private network is fine).
• Unique hostname, MAC address, and product_uuid for every node. See here for more details.
• Certain ports are open on your machines. See below for details
• sudo and ssh access on each of the nodes

Prepare

Install Dependencies

Kubernetes requires the following

• Container runtime (examples uses containerd)
• Container Networking Interface (CNI) plugin running (examples uses weavenet)
• Kubeadm
• Kubelet
• Kubectl

Official Docs

• Kubeadm installation guide
• Container Runtime installation guide

Configure

• Disabled memory Swap. You MUST disable swap in order for the kubelet to work properly.
• Configure the container runtime and kubelet to use the appropriate cgroup driver
• Load overlay and br_netfilter network modules on linux

Allow Ports

Control plane

• TCP Inbound 6443 Kubernetes API
• TCP Inbound 2379-2380 etcd server client API
• TCP Inbound 10250 Kubelet API
• TCP Inbound 10259 kube-scheduler
• TCP Inbound 10257 kube-controller-manager

Worker node(s)

• TCP Inbound 10250 Kubelet API
• TCP Inbound 30000-32767 NodePort Services

All nodes

• TCP Inbound 6783 Weavenet CNI Plugin
• UDP Inbound 6783-6784 Weavenet CNI Plugin