Query regarding compatibility of operating system

General Discussions
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1

Hello All,

I use kubeadm to create cluster on a baremetal or cloud servers. I would like to know about the compatibility of OS of nodes. I use Ubuntu servers and would like to know if the OS versions should exactly be the same or the minor versions mismatch are acceptable. For example, I have below cluster.

master node :
k8s version 1.20
containerd version: 1.4.12
OS version: Ubuntu 20.04.3

Worker1 :
k8s version 1.20
containerd version: 1.4.12
OS version: Ubuntu 20.04.3

Now I need to add one more node with below config

Worker2 :
k8s version 1.20
containerd version: 1.4.12
OS version: Ubuntu 20.04.4

Please let me know if it is acceptable. Also, I’m unable to find the compatibility matrix of OS on official docs. Please help me with the link if possible.

Cluster information:

Kubernetes version: 1.20.0
Cloud being used: bare-metal
Installation method: kubeadm
Host OS: Ubuntu Server 20.04
CNI and version: Calico 3.21
CRI and version: Containerd 1.4

Hope I have provided all the details. Please let me know if you need any additional details.

Regards,
Praveen

2

Minor versions like that generally shouldn’t matter too much, but you never know if a bug will wind up causing issues for part of your fleet. Long term I would try and converge on them being at the same patch level, but if its for things like rolling updates or A/B testing of updates it shouldn’t be too bad.