Upgrading Linux nodes

This page explains how to upgrade a Linux Worker Nodes created with kubeadm.

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

• Killercoda
• Play with Kubernetes

• Familiarize yourself with the process for upgrading the rest of your kubeadm cluster. You will want to upgrade the control plane nodes before upgrading your Linux Worker nodes.

Changing the package repository

If you're using the community-owned package repositories (pkgs.k8s.io), you need to enable the package repository for the desired Kubernetes minor release. This is explained in Changing the Kubernetes package repository document.

Upgrading worker nodes

Upgrade kubeadm

Upgrade kubeadm:

• Ubuntu, Debian or HypriotOS
• CentOS, RHEL or Fedora

# replace x in 1.26.x-* with the latest patch version
apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm='1.26.x-*' && \
apt-mark hold kubeadm

# replace x in 1.26.x-* with the latest patch version
yum install -y kubeadm-'1.26.x-*' --disableexcludes=kubernetes

Call "kubeadm upgrade"

• For worker nodes this upgrades the local kubelet configuration:

  sudo kubeadm upgrade node
  

Drain the node

• Prepare the node for maintenance by marking it unschedulable and evicting the workloads:

  # replace <node-to-drain> with the name of your node you are draining
  kubectl drain <node-to-drain> --ignore-daemonsets
  

Upgrade kubelet and kubectl

• Upgrade the kubelet and kubectl:

  • Ubuntu, Debian or HypriotOS
  • CentOS, RHEL or Fedora

  # replace x in 1.26.x-* with the latest patch version
  apt-mark unhold kubelet kubectl && \
  apt-get update && apt-get install -y kubelet='1.26.x-*' kubectl='1.26.x-*' && \
  apt-mark hold kubelet kubectl
  

  # replace x in 1.26.x-* with the latest patch version
  yum install -y kubelet-'1.26.x-*' kubectl-'1.26.x-*' --disableexcludes=kubernetes
  

  
  

• Restart the kubelet:

  sudo systemctl daemon-reload
  sudo systemctl restart kubelet
  

Uncordon the node

• Bring the node back online by marking it schedulable:

  # replace <node-to-uncordon> with the name of your node
  kubectl uncordon <node-to-uncordon>
  

What's next

• See how to Upgrade Windows nodes.