Pod terminated during upgrade process

Cluster information:

Kubernetes version: 1.21.2
Cloud being used: Baremetal
Installation method: Kubespray
Host OS: CentOS 7
CNI and version:
CRI and version:


I have installed the setup and I was trying to upgrade the K8s cluster to 1.21.4. During the upgraded process, when worker node was getting upgraded, a Pod running on it got terminated. My question why is Kubelet terminating a Pod even if container runtime is not being upgraded? Is there any specific reason behind this behavior?


The kubespray playbooks use kubeadm as the underlying tool.

All containers are restarted after upgrade, because the container spec hash value is changed.