Upgrading kubeadm clusters from v1.14 to v1.18

Posted on Thursday April 23, 2020

This page explains how to upgrade a Kubernetes cluster created with kubeadm from version 1.14.x to version 1.15.x, and from version 1.15.x to 1.18.y

The upgrade workflow at high level is the following:

Upgrade the primary control plane node.
Upgrade additional control plane nodes.
Upgrade worker nodes.

The Setup

The kubernetes cluster is running with 1- Master and 1 Worker node with the v1.14.0 our traget is get this cluster to v1.18.2 version. The enviroment is running on ubuntu platform, for centos family only the repository will chnage the concept will remain the same.

master $ kubectl get nodes
NAME     STATUS   ROLES    AGE   VERSION
master   Ready    master   73m   v1.14.0
node01   Ready    <none>   72m   v1.14.0

master $ kubectl version
Client Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.0", GitCommit:"641856db18352033a0d96dbc99153fa3b27298e5", GitTreeState:"clean", BuildDate:"2019-03-25T15:53:57Z", GoVersion:"go1.12.1", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.0", GitCommit:"641856db18352033a0d96dbc99153fa3b27298e5", GitTreeState:"clean", BuildDate:"2019-03-25T15:45:25Z", GoVersion:"go1.12.1", Compiler:"gc", Platform:"linux/amd64"}
master $ kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.0", GitCommit:"641856db18352033a0d96dbc99153fa3b27298e5", GitTreeState:"clean", BuildDate:"2019-03-25T15:51:21Z", GoVersion:"go1.12.1", Compiler:"gc", Platform:"linux/amd64"}
master $

node01 $ kubectl version
Client Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.0", GitCommit:"641856db18352033a0d96dbc99153fa3b27298e5", GitTreeState:"clean", BuildDate:"2019-03-25T15:53:57Z", GoVersion:"go1.12.1", Compiler:"gc", Platform:"linux/amd64"}
The connection to the server localhost:8080 was refused - did you specify the right host or port?
node01 $ kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.0", GitCommit:"641856db18352033a0d96dbc99153fa3b27298e5", GitTreeState:"clean", BuildDate:"2019-03-25T15:51:21Z", GoVersion:"go1.12.1", Compiler:"gc", Platform:"linux/amd64"}
node01 $

v1.14.x-v.1.15.x

Master Node - upgrade kubeadm

apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.15.11-00 && \
apt-mark hold kubeadm

kubeadm upgrade plan
kubeadm upgrade apply v1.15.11

Master Node - upgrade kubelet

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.15.11-00 kubectl=1.15.11-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Worker Node

Master Node - drain the Worker Node

kubectl drain node01 --ignore-daemonsets --delete-local-data

Worker Node - upgrade kubelet

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.15.11-00 kubectl=1.15.11-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Master Node - uncordon the Worker Node

kubectl uncordon node01

v1.15.x-v.1.16.x

Master Node - upgrade kubeadm

apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.16.9-00 && \
apt-mark hold kubeadm

kubeadm upgrade plan
kubeadm upgrade apply v1.16.9

Master Node - upgrade kubectl

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.16.9-00 kubectl=1.16.9-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Worker Node

Master Node - drain the Worker Node

kubectl drain node01 --ignore-daemonsets --delete-local-data

Worker Node - upgrade kubeadm

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubeadm=1.16.9-00 kubeadm=1.16.9-00 && \
apt-mark hold kubelet kubectl

kubeadm upgrade node

Worker Node - upgrade kubelet

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.16.9-00 kubectl=1.16.9-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Master Node - uncordon the Worker Node

kubectl uncordon node01

v1.16.x-v.1.17.x

Master Node - upgrade kubeadm

apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.17.5-00 && \
apt-mark hold kubeadm

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubeadm=1.17.5-00

kubeadm upgrade plan
kubeadm upgrade apply v1.17.5

Master Node - upgrade kubectl

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.17.5-00 kubectl=1.17.5-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Worker Node

Master Node - drain the Worker Node

kubectl drain node01 --ignore-daemonsets --delete-local-data

# replace x in 1.17.x-00 with the latest patch version
apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.17.5-00 && \
apt-mark hold kubeadm

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubeadm=1.17.5-00

Worker Node - upgrade kubeadm

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubeadm=1.17.5-00

kubeadm upgrade node

Worker Node - upgrade kubectl

# replace x in 1.17.x-00 with the latest patch version
apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.17.5-00 kubectl=1.17.5-00 && \
apt-mark hold kubelet kubectl

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubelet=1.17.5-00 kubectl=1.17.5-00

systemctl restart kubelet

Master Node - uncordon the Worker Node

kubectl uncordon node01

v1.17.x-v.1.18.x

Master Node - upgrade kubeadm

apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.18.2-00 && \
apt-mark hold kubeadm

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubeadm=1.18.2-00

kubeadm upgrade plan
kubeadm upgrade apply v1.18.2

Master Node - upgrade kubectl

# replace x in 1.18.x-00 with the latest patch version
apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.18.2-00 kubectl=1.18.2-00 && \
apt-mark hold kubelet kubectl

# since apt-get version 1.1 you can also use the following method
apt-get update && \
apt-get install -y --allow-change-held-packages kubelet=1.18.2-00 kubectl=1.18.2-00

systemctl restart kubelet

Worker Node

Master Node - drain the Worker Node

kubectl drain node01 --ignore-daemonsets --delete-local-data

Worker Node - upgrade kubeadm

apt-mark unhold kubeadm && \
apt-get update && apt-get install -y kubeadm=1.18.2-00 && \
apt-mark hold kubeadm

Worker Node - upgrade kubectl

apt-mark unhold kubelet kubectl && \
apt-get update && apt-get install -y kubelet=1.18.2-00 kubectl=1.18.2-00 && \
apt-mark hold kubelet kubectl

systemctl restart kubelet

Master Node - uncordon the Worker Node

kubectl uncordon node01

since it's kubernetes you may encounter some issues, feel free to poke me

Video Demo for Ubuntu v1.14-v1.18

Video Demo for RHEL

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