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kubectl-cheatsheet.md

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WARNING WARNING WARNING WARNING WARNING

PLEASE NOTE: This document applies to the HEAD of the source tree

If you are using a released version of Kubernetes, you should refer to the docs that go with that version.

Documentation for other releases can be found at releases.k8s.io.

An assortment of compact kubectl examples

See also: Kubectl overview and JsonPath guide.

Creating Objects

$ kubectl create -f ./file.yml                   # create resource(s) in a json or yaml file

$ kubectl create -f ./file1.yml -f ./file2.yaml  # create resource(s) in a json or yaml file

$ kubectl create -f ./dir                        # create resources in all .json, .yml, and .yaml files in dir

# Create from a URL
$ kubectl create -f http://www.fpaste.org/279276/48569091/raw/

# Create multiple YAML objects from stdin
$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "1000000"
---
apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep-less
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "1000"
EOF

# Create a secret with several keys
$ cat <<EOF | kubectl create -f -
apiVersion: v1
kind: Secret
metadata:
  name: mysecret
type: Opaque
data:
  password: $(echo "s33msi4" | base64)
  username: $(echo "jane" | base64)
EOF

# TODO: kubectl-explain example

Viewing, Finding Resources

# Columnar output
$ kubectl get services                          # List all services in the namespace
$ kubectl get pods --all-namespaces             # List all pods in all namespaces
$ kubectl get pods -o wide                      # List all pods in the namespace, with more details
$ kubectl get rc <rc-name>                      # List a particular replication controller
$ kubectl get replicationcontroller <rc-name>   # List a particular RC

# Verbose output
$ kubectl describe nodes <node-name>
$ kubectl describe pods <pod-name>
$ kubectl describe pods/<pod-name>              # Equivalent to previous
$ kubectl describe pods <rc-name>               # Lists pods created by <rc-name> using common prefix

# List Services Sorted by Name
$ kubectl get services --sort-by=.metadata.name

# List pods Sorted by Restart Count
$ kubectl get pods --sort-by=.status.containerStatuses[0].restartCount

# Get the version label of all pods with label app=cassandra
$ kubectl get pods --selector=app=cassandra rc -o 'jsonpath={.items[*].metadata.labels.version}'

# Get ExternalIPs of all nodes
$ kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=ExternalIP)].address}'

# List Names of Pods that belong to Particular RC
# "jq" command useful for transformations that are too complex for jsonpath
$ sel=$(./kubectl get rc <rc-name> --output=json | jq -j '.spec.selector | to_entries | .[] | "\(.key)=\(.value),"')
$ sel=${sel%?} # Remove trailing comma
$ pods=$(kubectl get pods --selector=$sel --output=jsonpath={.items..metadata.name})`

# Check which nodes are ready
$ kubectl get nodes -o jsonpath='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}'| tr ';' "\n"  | grep "Ready=True"

Modifying and Deleting Resources

$ kubectl label pods <pod-name> new-label=awesome                  # Add a Label
$ kubectl annotate pods <pod-name> icon-url=http://goo.gl/XXBTWq   # Add an annotation

# TODO: examples of kubectl edit, patch, delete, replace, scale, and rolling-update commands.

Interacting with running Pods

$ kubectl logs <pod-name>         # dump pod logs (stdout)
$ kubectl logs -f <pod-name>      # stream pod logs (stdout) until canceled (ctrl-c) or timeout

$ kubectl run -i --tty busybox --image=busybox -- sh      # Run pod as interactive shell
$ kubectl attach <podname> -i                             # Attach to Running Container
$ kubectl port-forward <podname> <local-and-remote-port>  # Forward port of Pod to your local machine
$ kubectl port-forward <servicename> <port>               # Forward port to service
$ kubectl exec <pod-name> -- ls /                         # Run command in existing pod (1 container case) 
$ kubectl exec <pod-name> -c <container-name> -- ls /     # Run command in existing pod (multi-container case)

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