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11.0 - Install Kubernetes the Kubeadm Way

  1. Decide on Configuration - Master vs Worker
  2. Install a container runtime (Docker, etc.)
  3. Install Kubeadm
  4. Initialise the Master Node
  5. Pod Network Setup
  6. Join worker nodes to the master node

Resources

Deploy with Kubeadm - Provision VMs with Vagrant

  • Using links above, and ensuring Virtualbox and vagrant are installed, clone the repo and run vagrant up
  • This will pull the images for the vms defined and kubernetes, creating a kubernetes master node and 2 workers
  • To access any, vagrant ssh <vm name> (can run commands to test things)
  • Check status with vagrant status

Demo - Deploy with Kubeadm

  • Ssh into kubemaster: vagrant ssh kubemaster
  • Check br_nefilter is deployed: lsmod | grep br_netfilter
  • Allows iptables to can see bridged traffic
  • Load the kernel module: sudo modprobe br_netfilter

  • Run the previous lsmod command for verification and repeat for each node.

  • Load the relevant modules and iptables settings into a k8s.conf file:

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sudo sysctl --system
  • Run the rest as sudo by default: sudo -i
  • Install container runtime e.g. Docker via supporting documentation.

  • Install kubeadm, kubectl and kubelet via supporting documentation.

  • Note: If not using Docker as the container runtime, additional configuration may be needed for the CGroup

  • Creating the cluster starts with initializing the master node: kubadm init --pod-network-cidrs <range> --apiserver-advertise-address <masternode address>

  • Command sample: kubeadm init --pod-network-cidr 10.244.0.0/16 --apiserver-advertise-address=192.168.56.2

  • Install a pod network addon upon initialization e.g. Flannel, Weave, Calico; each has their own supporting documentation for this.

  • Once complete, instructions are provided on how to start using the cluster, including setting the kubeconfig location and ownership.

  • Worker nodes can be added to the cluster by running the provided command upon initialisation: sudo kubeadm join .... <parameters>