Kubernetes Essential Commands

Here are some essential commands using kubectl.

1- Get worker nodes status and verify if kubernetes worker nodes are ready.

Commands	Description
az aks get-credentials --resource-group aks-resgrp --name demo	Configure Cluster Creds (kube config) for Azure AKS Clusters
kubectl get nodes	Get Worker Node Status
kubectl get nodes -o wide	Get Worker Node Status with wide option

2- Create Kubernetes Pod

Commands	Description
kubectl run <pod-name> --image <Docker-Container-Image>	Create Kubernetes pod by providing pod name and docker container image
Eg. kubectl run demo-pod --image asif120/demodocker:1.0.0	Replace Pod Name,Docker Container Image In above given commands

1. Kubernetes created a pod
2. Pulled the docker image from docker hub
3. Created the container in the pod
4. Started the container present in the pod

3- Get the list of pods

Commands	Description
kubectl get pods	Get the list of pods
kubectl get pods -o wide	Get the list of pods with wide option which also provide Node information on which Pod is running
kubectl get po	Giving alias name for pods is po

4- Describe pods helps during troubleshooting.

Commands	Description
kubectl get pods	Get the list of pods
kubectl describe pod <Pod-Name>	Describe the pod details .Events will be shown it will be helpful during troubleshooting
Eg . kubectl describe pod demo-pod	Replace pod name in above given command.

5- Delete pod details

Commands	Description
kubectl get pods	Get the list of pods
kubectl delete pod <Pod-Name>	Delete the pod
Eg . kubectl delete pod demo-pod	Replace pod name in above given command

6- Expose pods with service (Load Balancer Service) to access application externally  (from internet) .Currently we can access this application only inside worker nodes.To access it externally, we need to create a NodePort or Load Balancer Service.

Ports

• Port: Port on which node port service listens in Kubernetes cluster internally
• targetPort: We define container port here on which our application is running.

Commands	Description
kubectl expose pod <Pod-Name>  --type=LoadBalancer --port=80 --name=<Service-Name>	Expose Pod as a Service
Eg . kubectl expose pod pod-demo  --type=LoadBalancer --port=80 --name=demo-service	Replace pod and service name in above commands
kubectl get service	Get Service Info
kubectl get svc	Get Service Info
kubectl describe service demo-service	Describe Service to get more details for troubleshooting
http://<External-IP-from-get-service-output>	Access Application

Verify Azure Standard Load Balancer created for Azure AKS Cluster

• Frontend IP Configuration
• Load Balancing Rules
• Azure Public IP

7- Get more pod logs for troubleshooting using kubectl

Commands	Description
kubectl get po	Get Pod Name
kubectl logs <pod-name> kubectl logs demo-pod	Dump Pod logs
kubectl logs <pod-name> kubectl logs -f demo-pod	Stream pod logs with -f option and access application to see logs

Reference for Interacting with running Pods for additional log options: kubectl Cheat Sheet | Kubernetes

8- Get YAML Output of Pod & Service

Commands	Description
kubectl get pod my-first-pod -o yaml	Get pod definition YAML output
kubectl get service my-first-service -o yaml	Get service definition YAML output

9- Other useful commands

Commands	Description
kubectl exec -it <pod-name> -- /bin/bash kubectl exec -it demo-pod -- /bin/bash	Connect to a ngnix Container in POD and execute commands
kubectl exec -it <pod-name> -- env kubectl exec -it demo-pod -- env kubectl exec -it demo-pod -- ls	Execute some running individual commands in a Container
kubectl get all	Get all Objects in default namespace
kubectl delete svc demo-service	Delete Services
kubectl delete pod demo-pod	Delete Pod