Commonly Used Commands in Kubernetes, Docker, and Containerd
Kubernetes
To check if kubelet is working
systemctl status kubelet
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To check the Linux system logs when kubelet has an error
journalctl -xeu kubelet
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To check the kubelet logs when it has any error
kubectl get events --all-namespaces --sort-by='.metadata.creationTimestamp'
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To check the Pod logs
kubectl logs <POD_NAME> -n <NAMESPACE>
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To check the previous Pod logs if it is seen it restarted at least one time
kubectl logs --previous <POD_NAME> -n apinizer
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To check if there exist any general error on Pod or see the details of Pod
kubectl describe pod <POD_NAME> -n apinizer
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To execute any command inside of a working Pod
kubectl exec -it <POD_NAME> -n prod /bin/bash
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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
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To restart all pods under a specific deployment
kubectl rollout restart deployment manager -n apinizer
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- Bir deployment altındaki podların sayısınıfı sıfıra çekmek için
kubectl scale deploy cache -n prod --replicas=0
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To delete a deployment as a whole
kubectl delete -f apinizer-deployment.yaml
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To force a Pod to delete if it stucks on status "terminating"
kubectl delete pod <POD_NAME> -n apinizer --grace-period=0 --force
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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
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To clean up pods in the "Evicted" state
kubectl get pod -n prod | grep Evicted | awk '{print $1}' | xargs kubectl delete pod -n prod
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Preventing Pod from Running on Specific Nodes Using Kubernetes Node Affinity
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: NotIn
values:
- kuberdemo55
- kuberdemo56
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Docker
Image listing
docker images
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List All Containers
docker ps -a
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Image Pull
sudo docker pull apinizercloud/manager:2024.xx.0
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Image Export
sudo docker save apinizercloud/manager:2024.xx.0 > manager_2024.xx.0.tar
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Image Import
sudo docker load < manager_2024.xx.0.tar
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Containerd
Namespace Listing
sudo ctr namespaces list
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Containers listing with namespace
sudo ctr --namespace k8s.io containers ls
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Images of Apinizer listing with namespace
sudo ctr -n k8s.io images list | grep apinizer
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Image Pull
sudo ctr --namespace k8s.io images pull docker.io/apinizercloud/manager:2024.05.0
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Image Export
sudo ctr -n k8s.io images export /tmp/manager:2024.05.0.tar docker.io/apinizercloud/manager:2024.05.0
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Image Import
sudo ctr --namespace k8s.io images import /tmp/manager:2024.05.0.tar
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