Commonly Used Commands in Kubernetes, Docker, and Containerd

• To check if kubelet is working

systemctl status kubelet

• To check the Linux system logs when kubelet has an error

journalctl -xeu kubelet

• To check the kubelet logs when it has any error

kubectl get events --all-namespaces  --sort-by='.metadata.creationTimestamp'

• To check the Pod logs

kubectl logs <POD_NAME> -n <NAMESPACE> 

• To check the previous Pod logs if it is seen it restarted at least one time

kubectl logs --previous <POD_NAME> -n apinizer

• To check if there exist any general error on Pod or see the details of Pod

kubectl describe pod <POD_NAME> -n apinizer

• To execute any command inside of a working Pod

kubectl exec -it  <POD_NAME> -n prod /bin/bash

• To execute any command as it is from inside without getting inside of a working Pod

kubectl exec -it  <POD_NAME> -n prod -- curl x.y.gov.tr

• To restart all pods under a specific deployment

kubectl rollout restart deployment manager -n apinizer

• To delete a deployment as a whole

kubectl delete -f  apinizer-deployment.yaml

• To force a Pod to delete if it stucks on status "terminating"

kubectl delete pod <POD_NAME> -n apinizer --grace-period=0 --force 

• To update version when the necessary images loaded on the servers' dockers'. It is worked like "vi" editor which it needs to do ":wq" to save and exit and ":q!" to exit without save.

kubectl edit deployment manager -n apinizer
kubectl edit deployment cache -n prod
kubectl edit deployment worker -n prod

• To clean up pods in the "Evicted" state

kubectl get pod -n prod | grep Evicted | awk '{print $1}' | xargs kubectl delete pod -n prod

Docker

Containerd