Upgrading Kubernetes from v1.32.0 to v1.33.0 with kubeadm

Overview

Keeping your Kubernetes cluster up to date is crucial for security, stability, and access to the latest features.

In this tutorial, we’ll walk through upgrading a kubeadm-managed Kubernetes cluster from v1.32.0 to v1.33.0, following official best practices and real-world operational insights.

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Why Upgrade?

Each Kubernetes release introduces performance improvements, API enhancements, and critical security fixes.
The 1.33 release includes:

Native Sidecar Containers (Stable), official support for true sidecar lifecycle management
In-place Pod Resource Resizing (Beta)
API Deprecations & Cleanup, Endpoints API deprecated in favor of EndpointSlices
Improved Security Controls and RBAC refinements

Before upgrading production clusters, always test the upgrade in a staging environment, and ensure you have etcd snapshots and deployment manifests backed up.

Prerequisites

Before starting, make sure you meet these requirements:

Existing Cluster: Running Kubernetes v1.32.0 using kubeadm
SSH Access: Root or sudo privileges on all nodes
Internet Access: Nodes can reach Kubernetes package repositories
Backups Taken:

# Take etcd snapshot
ETCDCTL_API=3 etcdctl snapshot save /root/etcd-snapshot.db

1 2	# Take etcd snapshot ETCDCTL_API=3 etcdctl snapshot save /root/etcd-snapshot.db

5. Cluster Health:

kubectl get nodes
kubectl get pods -A

1 2	kubectl get nodes kubectl get pods -A

All nodes and core system pods should be in the Ready state.

kub

Step-by-Step Guide

Step 1: Make the controlplane UnSchedulable

kubectl drain controlplane --ignore-daemonsets

1	kubectl drain controlplane --ignore-daemonsets

step1

Step 2: Verify the package repository

pager /etc/apt/sources.list.d/kubernetes.list

1	pager /etc/apt/sources.list.d/kubernetes.list

Modify the version 1.32 to 1.33 so that you can upgrade

Step 3: Find the latest patch release for 1.33 using os package manager

sudo apt update
sudo apt-cache madison kubeadm

1 2	sudo apt update sudo apt-cache madison kubeadm

step3

So you can see we can upgrade to all these possible versions, but I will move ahead with the 1.33.0-1.1 version for this demo

Make sure you copy that

Step 4: Now, let’s upgrade the control plane

sudo apt-mark unhold kubeadm && \
sudo apt-get update && sudo apt-get install -y kubeadm='1.33.0-1.1' && \
sudo apt-mark hold kubedam

sudo apt-mark unhold kubeadm && \

sudo apt-get update && sudo apt-get install -y kubeadm='1.33.0-1.1' && \

sudo apt-mark hold kubedam

step4

So now kubedam is updated to the new version.

step4b

Step 5: Let’s plan the upgrade

sudo kubeadm upgrade plan

1	sudo kubeadm upgrade plan

step5

step5b

step5c

Step 6: Now upgrade to your desired version ( 1.33.0)

kubeadm upgrade apply v1.33.0

1	kubeadm upgrade apply v1.33.0

step6

Note that this step usually takes 5-10 minutes.

step6b

Step 7: Now let’s upgrade kubectl and kubelet as well

sudo apt-mark unhold kubelet kubectl && \
sudo apt-get update && sudo apt-get install -y kubelet='1.33.0-1.1' kubectl='1.33.0-1.1' && \
sudo apt-mark hold kubelet kubectl

sudo apt-mark unhold kubelet kubectl && \

sudo apt-get update && sudo apt-get install -y kubelet='1.33.0-1.1' kubectl='1.33.0-1.1' && \

sudo apt-mark hold kubelet kubectl

step7

Step 8: Once that’s done, make sure you restart the kubelet

sudo systemctl daemon-reload
sudo systemctl restart kubelet

1 2	sudo systemctl daemon-reload sudo systemctl restart kubelet

step8

Now, let’s make the node uncordon ( so they can schedule pods)

kubectl uncordon controlplane

step8b

Step 9: Now, let’s jump into upgrading worker nodes (node01)

Let’s make them first unscheduled

kubectl drain node01 --ignore-daemonsets

1	kubectl drain node01 --ignore-daemonsets

step9

Step 10: Let’s SSH into node01 to perform upgradation

step10

Step 11: Let’s update the Kubernetes package repository list.

pager /etc/apt/sources.list.d/kubernetes.list

1	pager /etc/apt/sources.list.d/kubernetes.list

step11

Step 12: Now let’s upgrade kubelet & kubectl.

sudo apt-mark unhold kubelet kubectl && \
sudo apt-get update && sudo apt-get install -y kubelet='1.33.0-1.1' kubectl='1.33.0-1.1' && \
sudo apt-mark hold kubelet kubectl

sudo apt-mark unhold kubelet kubectl && \

sudo apt-get update && sudo apt-get install -y kubelet='1.33.0-1.1' kubectl='1.33.0-1.1' && \

sudo apt-mark hold kubelet kubectl

step12

Step 13: Once that’s done, let’s restart kubelet

sudo systemctl daemon-reload
sudo systemctl restart kubelet

1 2	sudo systemctl daemon-reload sudo systemctl restart kubelet

step13

Now, exit or log out from node01 (worker node)

Step 14: Now let’s uncordon this node so pods can be scheduled and verify the upgradation

Kubectl uncordon node01

1	Kubectl uncordon node01

step14

Step 15: Check all system components

kubectl get pods -n kube-system

1	kubectl get pods -n kube-system

Rollback Plan (Optional but Important)

If something goes wrong:

Restore your etcd snapshot:

ETCDCTL_API=3 etcdctl snapshot restore /root/etcd-snapshot.db

1	ETCDCTL_API=3 etcdctl snapshot restore /root/etcd-snapshot.db

Revert node packages to v1.32.0:

sudo apt-get install kubeadm=1.32.0-00 kubelet=1.32.0-00 kubectl=1.32.0-00

1	sudo apt-get install kubeadm=1.32.0-00 kubelet=1.32.0-00 kubectl=1.32.0-00

Final Checklist

Etcd Backup Taken
Control Plane Upgraded
Worker Nodes Upgraded
Kubelet Restarted
Cluster Verified

Conclusion

Upgrading a Kubernetes cluster might seem daunting, but with kubeadm, it’s a clean, predictable, and reversible process.
By upgrading from v1.32.0 to v1.33.0, you ensure that your environment benefits from the latest security patches, improved performance, and new stable features, such as sidecar containers and pod resizing.

Drop a query if you have any questions regarding Kubernetes and we will get back to you quickly.

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About CloudThat

CloudThat is an award-winning company and the first in India to offer cloud training and consulting services worldwide. As a Microsoft Solutions Partner, AWS Advanced Tier Training Partner, and Google Cloud Platform Partner, CloudThat has empowered over 850,000 professionals through 600+ cloud certifications winning global recognition for its training excellence including 20 MCT Trainers in Microsoft’s Global Top 100 and an impressive 12 awards in the last 8 years. CloudThat specializes in Cloud Migration, Data Platforms, DevOps, IoT, and cutting-edge technologies like Gen AI & AI/ML. It has delivered over 500 consulting projects for 250+ organizations in 30+ countries as it continues to empower professionals and enterprises to thrive in the digital-first world.

WRITTEN BY Akshay Ramnani

Akshay Ramnani works as a DevOps Engineer with over 3 years of hands-on experience in architecting CI/CD pipelines, Kubernetes-based deployments, and multi-cloud automation across AWS, GCP, and Azure. He has a proven track record in scaling microservices on Amazon EKS, streamlining observability platforms, and driving infrastructure as code using Terraform, Helm, and ArgoCD.