Kubernetes Docker Containerd Commands

Provides frequently used commands for Kubernetes, Docker, and Containerd. Offers practical command examples for daily operational tasks such as pod management, log viewing, deployment operations, and image management.

Kubernetes Commands

Kubelet Status Check

Checking kubelet service status:

systemctl status kubelet

Viewing kubelet errors from Linux system:

journalctl -xeu kubelet

Viewing kubelet errors from Kubernetes:

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

Pod Log and Status Check

Viewing pod logs:

kubectl logs <POD_NAME> -n <NAMESPACE>

Viewing previous pod logs (if pod was restarted):

kubectl logs --previous <POD_NAME> -n apinizer

Viewing pod details:

kubectl describe pod <POD_NAME> -n apinizer

Pod Operations

Entering pod:

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

Making request without entering pod:

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

Deployment Operations

Restarting deployment:

kubectl rollout restart deployment manager -n apinizer

Setting deployment replica count:

kubectl scale deploy cache -n prod --replicas=0

Deleting deployment:

kubectl delete -f apinizer-deployment.yaml

Force deleting pod in Terminating state:

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

Version update:

After pulling images to servers, the following commands are used. These commands work like the “vi” editor, use “:wq” to save and exit.

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

Cleaning evicted pods:

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

Node Affinity Configuration

Preventing pod from running on specific nodes:

affinity:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: NotIn
              values:
                - kuberdemo55
                - kuberdemo56

Docker Commands

Image Operations

Listing images:

docker images

Listing all containers:

docker ps -a

Image pull operation:

sudo docker pull apinizercloud/manager:2024.xx.0

Image export:

sudo docker save apinizercloud/manager:2024.xx.0 > manager_2024.xx.0.tar

Image import:

sudo docker load < manager_2024.xx.0.tar

Containerd Commands

Namespace Operations

Listing namespaces:

sudo ctr namespaces list

Listing containers by namespace:

sudo ctr --namespace k8s.io containers ls

Image Operations

Listing Apinizer images:

sudo ctr -n k8s.io images list | grep apinizer

Image pull operation:

sudo ctr --namespace k8s.io images pull docker.io/apinizercloud/manager:2024.05.0

Image export:

sudo ctr -n k8s.io images export /tmp/manager:2024.05.0.tar docker.io/apinizercloud/manager:2024.05.0

Image import:

sudo ctr --namespace k8s.io images import /tmp/manager:2024.05.0.tar