Kubectl

Global

Change current context

kubectl config use-context <context_name>

Change current namespace

kubectl config set-context --current --namespace <namespace>

Get resource in every namespace

kubectl get <resource> -A

Show more resource infos

kubectl get <resource> -o wide

Apply resource from stdin

cat <file> | kubectl apply -f -

or

kubectl apply -f - <<EOF
<-- insert YAML content here -->
EOF

Pods

Get pod by node

kubectl get pods -A -o wide --field-selector spec.nodeName=<node>

Get pod by label

kubectl get pods -A -o wide -l <key>=<value>

Get pod labels

kubectl get pod --show-labels

Copy file or directory from local to container

kubectl cp <local_path> <namespace>/<pod_name>:<container_path>

Copy file or directory from container to local

kubectl cp <namespace>/<pod_name>:<container_path> <local_path>

Copy file or directory from one container to another

kubectl exec <source_pod_name> -- tar cf - <source_container_path> | kubectl exec -i <target_pod_name> -- tar xvf - -C <target_container_path>

Get pod quotas

kubectl get pods -A -o custom-columns='NAME:.metadata.name,CPU_REQ:spec.containers[].resources.requests.cpu,CPU_LIM:spec.containers[].resources.limits.cpu,MEM_REQ:spec.containers[].resources.requests.memory,MEM_LIM:spec.containers[].resources.limits.memory'

Nodes

Get node labels

kubectl get nodes --show-labels

Make a node unschedulable and remove workloads from it

kubectl drain <node_name> --ignore-daemonsets --delete-emptydir-data

Make a node unschedulable

kubectl cordon <node_name>

Remove a node from the cluster

kubectl delete node <node_name>

Make a node schedulable

kubectl uncordon <node_name>

Secrets

Create and apply secret

echo "apiVersion: v1
kind: Secret
type: Opaque 
metadata:
  name: <secret_name>
  namespace: <namespace>
stringData:
  foo: bar" \
  | kubectl apply -f -

Create and apply secret from file

kubectl create secret -n <namespace> generic <secret_name> \
  --from-file=<file_name>.yaml \
  --dry-run=client \
  -o yaml \
  | kubectl apply -f -

Read secret

kubectl -n <namespace> get secret <secret_name> -o jsonpath="{.data.<data_field>}" | base64 --decode

Read secret (all fileds)

kubectl -n <namespace> get secret <secret_name> -o yaml | yq '.data | map_values(. | @base64d)'

Network

Forward port

kubectl port-forward -n <namespace> svc/<service_name> <host_port>:<service_port>

or

kubectl port-forward -n <namespace> pod/<pod_name> <host_port>:<pod_port>