I upgraded from Kubernetes plugin 1.16 to 1.21 and suddenly many of our Jenkins slaves stopped working. We found that the issue is caused by the default HOME environment variable that the plugin adds to all containers in Jenkins slave pods in Openshift. https://github.com/jenkinsci/kubernetes-plugin/blob/33737fe0c96615e33b78205fe6e71aaffca2df49/src/main/java/org/csanchez/jenkins/plugins/kubernetes/PodTemplateBuilder.java#L104

That variable has a default value of /home/jenkins but if that folder does not exist then the container can fail.