Kubernetes(k8s) Sample Commands - 02

Following are a few of the  kubectl commands for managing Kubernetes clusters:

• kubectl get nodes -o=jsonpath='{XX}'
• This command retrieves information about the nodes in the cluster using the jsonpath output format. Replace {XX} with the desired path.
• kubectl get nodes -o=custom-columns=<Column name>
• This command retrieves information about the nodes in the cluster using custom columns output format. Replace <Column name> with the desired column name
• --sort-by=
• This option is used to sort the output based on a specified field.
• kubectl get node node01 -o json > /opt/outputs/node01.json
• This command retrieves information about a specific node and saves it as a JSON file.
• kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.osImage}' > /opt/outputs/nodes_os.txt
• This command retrieves the OS image of all the nodes in the cluster and saves it in a text file.
• kubectl config view --kubeconfig=my-kube-config -o jsonpath="{.users[*].name}" > /opt/outputs/users.txt
• This command retrieves the names of all users in the kubeconfig file and saves it in a text file.
• kubectl get pv --sort-by=.spec.capacity.storage > /opt/outputs/storage-capacity-sorted.txt
• This command retrieves the capacity of all persistent volumes and sorts the output by storage capacity.
• kubectl config view --kubeconfig=my-kube-config -o jsonpath="{.contexts[?(@.context.user=='aws-user')].name}" > /opt/outputs/aws-context-name
• This command retrieves the context name for a specific user in the kubeconfig file.
• kubectl run test-nslookup --image=busybox:1.28 --rm -it --restart=Never -- nslookup nginx-resolver-service
• This command creates a pod named test-nslookup and runs a DNS lookup on nginx-resolver-service.
• kubectl run test-nslookup --image=busybox:1.28 --rm -it --restart=Never -- nslookup nginx-resolver-service > /root/CKA/nginx.svc
• This command creates a pod named test-nslookup and redirects the output of the DNS lookup to a file.
• K get nodes -o jason | jq -c paths |grep type
• This command retrieves the paths of all fields in the node objects in the cluster that contain the word "type".
• kubectl create deployment --image=nginx nginx --replicas=4 --dry-run=client -o yaml > nginx-deployment.yaml
• This command creates a deployment named nginx with 4 replicas and saves the deployment manifest as a YAML file. The --dry-run=client flag is used to simulate the deployment without actually creating it.