kubectl cluster-info

kubectl get nodes # list all nodes in the cluster
kubectl get pods # list all pods in the namespace or with --all-namespaces flag
kubectl get services
kubectl get deployments
kubectl get secrets
kubectl edit <resource-type> <resource-name> # edit a resource in the default editor
watch -n 2 kubectl get pods  # Continuously monitor pod status every X seconds

--all-namespaces # list the requested object(s) across all namespaces
--watch # after listing/getting the requested object, watch for changes
-o # output format example -o yaml or -o json
--show-labels # show labels in the last column
--selector # filter results by label selector example --selector env=prod
--sort-by # sort list types using a jsonpath expression example --sort-by='{.metadata.name}'
--field-selector # filter results by a field selector example --field-selector metadata.name=nginx
--no-headers # when using the default or custom-column output format, don't print headers (default print headers) 
--output-watch-events # output watch event objects when --watch or --watch-only is used example kube get pods --watch --output-watch-events

kubectl describe nodes <node-name>
kubectl describe pods <pod-name>
kubectl describe services <service-name>
kubectl describe deployments <deployment-name>
kubectl explain <resource-type> # get the documentation of a resource type example kubectl explain pods

kubectl create -f <file-name>
kubectl apply -f <file-name>

kubectl delete pods <pod-name>
kubectl delete services <service-name>
kubectl delete -f <file-name>
kubectl delete deployment <deployment-name> # delete a deployment
kubectl delete namespace <namespace-name> # delete a namespace

kubectl scale deployment <deployment-name> --replicas=<number-of-replicas>

kubectl expose deployment <deployment-name> --type=ClusterIP --port=<port> # Exposes the service on a cluster-internal IP. Choosing this value makes the service only reachable from within the cluster.
kubectl expose deployment <deployment-name> --type=NodePort --port=<port>
kubectl expose deployment <deployment-name> --type=LoadBalancer --port=<port> # In cloud providers that support load balancers, an external IP address would be provisioned to access the service.

kubectl rollout status deployment <deployment-name> # Check the status of a rollout
kubectl rollout history deployment <deployment-name> # Check the history of a rollout
kubectl rollout undo deployment <deployment-name> # Rollback to the previous revision
kubectl rollout undo deployment <deployment-name> --to-revision=<revision-number> # Rollback to a specific revision

kubectl logs <pod-name> -n <namespace> # print the logs for a pod in a namespace
kubectl logs -f <pod-name> # follow the logs
kubectl logs -p <pod-name> # print the logs for the previous instance of the container in a pod if it exists

kubectl exec <pod-name> -- <command> # execute a command in a container
kubectl exec -it <pod-name> -- <command> # execute a command in a container interactively
# enter the container's shell
kubectl exec -it <pod-name> -- /bin/bash # bash shell, very common to get into a container
# copy files to and from a container
kubectl cp <pod-name>:<path-to-file> <path-to-local-file> -c <container-name>
kubectl cp <path-to-local-file> <pod-name>:<path-to-file> -c <container-name>

kubectl port-forward <pod-name> <local-port>:<container-port>
kubectl port-forward <service-name> <local-port>:<container-port>

kubectl label pods <pod-name> <label-key>=<label-value>
kubectl annotate pods <pod-name> <annotation-key>=<annotation-value>

kubectl taint nodes <node-name> <key>=<value>:<effect> # taint a node
kubectl taint nodes <node-name> <key>:<effect> # remove a taint from a node
kubectl taint nodes <node-name> <key>:NoSchedule # prevent pods from being scheduled on the node
kubectl taint nodes <node-name> <key>:NoExecute # prevent pods from being scheduled on the node and evict existing pods
kubectl taint nodes <node-name> <key>:PreferNoSchedule # prefer not to schedule pods on the node

kubectl config view # display merged kubeconfig settings or a specified kubeconfig file
kubectl config view --minify --output 'jsonpath={..namespace}' # display the namespace within the context
kubectl config current-context # display the current-context
kubectl config use-context <context-name> # set the current-context in a kubeconfig file
kubectl config set-context <context-name> # set a context entry in kubeconfig
kubectl config set-cluster <cluster-name> # set a cluster entry in kubeconfig
kubectl config set-credentials <user-name> # set a user entry in kubeconfig
kubectl config unset users.<name> # unset a user entry in kubeconfig

kubectl config set-cluster <cluster-name> \
  --certificate-authority=<path-to-ca-file> \
  --embed-certs=<true|false> \
  --server=<address-and-port-of-api-server> \
  --kubeconfig=<path-to-kubeconfig-file>

kubectl apply --dry-run=client -f <file-name>

kubectl get pods -o name | cut -d/ -f2 | xargs -I {} kubectl delete pod {}
for pod in $(kubectl get pods -o name | cut -d/ -f2); do kubectl delete pod $pod; done

 kubectl get secrets -o json | jq -r '.items[] | .metadata.name as $name | .data | to_entries[] | "\($name) \(.key): \((.value|@base64d))"'

cat <<EOF | kubectl create -f -
# create a n nginx pod
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
    containers:
    - name: nginx
        image: nginx
EOF

kubectl api-resources
kubectl api-resources --namespaced=true # namespaced resources
# how to get curl call from kubectl with log level 9
kubectl get pods -v=9  2>&1 | grep curl # get curl call for a specific resource
kubectl get pods -v=9  2>&1 | grep curl | sed 's/.*curl -k -v -XGET/https/' | sed 's/ -H .*//' # get curl call for a specific resource

KUBECONFIG=~/.kube/config:~/.kube/config2:~/.kube/config3 kubectl config view --flatten > ~/.kube/merged-config

export KUBECONFIG=~/.kube/merged-config