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Improving kubectl cheat sheet (#1486) 

* Improving kubectl cheatsheet

* removing sentence and some cleanup
pull/1487/head
Chris Love 2016-10-24 18:56:11 -06:00 committed by Steve Perry
parent 7fc7c2c118
commit 8f02f91f53
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docs/user-guide/kubectl-cheatsheet.md
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@ -3,24 +3,57 @@ assignees:
- bgrant0607
- erictune
- krousey
- clove
---
An assortment of compact kubectl examples
See also: [Kubectl overview](/docs/user-guide/kubectl-overview/) and [JsonPath guide](/docs/user-guide/jsonpath).
See also: [Kubectl Overview](/docs/user-guide/kubectl-overview/) and [JsonPath Guide](/docs/user-guide/jsonpath).
## Kubectl Autocomplete
```console
$ source <(kubectl completion bash) # setup autocomplete in bash
$ source <(kubectl completion zsh) # setup autocomplete in zsh
```
## Kubectl Context and Configuration
Set which Kubernetes cluster `kubectl` communicates with and modify configuration
information. See [kubeconfig file](/docs/user-guide/kubeconfig-file/) documentation for
detailed config file information.
```console
$ kubectl config view # Show Merged kubeconfig settings.
# use multiple kubeconfig files at the same time and view merged config
$ KUBECONFIG=~/.kube/config:~/.kube/kubconfig2 kubectl config view
# Get the password for the e2e user
$ kubectl config view -o jsonpath='{.users[?(@.name == "e2e")].user.password}'
$ kubectl config current-context # Display the current-context
$ kubectl config use-context my-cluster-name # set the default context to my-cluster-name
# add a new cluster to your kubeconf that supports basic auth
$ kubectl config set-credentials kubeuser/foo.kubernetes.com --username=kubeuser --password=kubepassword
# set a context utilizing a specific username and namespace.
$ kubectl config set-context gce --user=cluster-admin --namespace=foo \
&& kubectl config use-context gce
```
## Creating Objects
```shell
$ kubectl create -f ./file.yml # create resource(s) in a json or yaml file
Kubernetes manifests can be defined in json or yaml. The file extension `.yaml`,
`.yml`, and `.json` can be used.
$ 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/
```console
$ kubectl create -f ./my-manifest.yaml # create resource(s)
$ kubectl create -f ./my1.yaml -f ./my2.yaml # create from multiple files
$ kubectl create -f ./dir # create resource(s) in all manifest files in dir
$ kubectl create -f https://git.io/vPieo # create resource(s) from url
$ kubectl run nginx --image=nginx # start a single instance of nginx
$ kubectl explain pods,svc # get the documentation for pod and svc manifests
# Create multiple YAML objects from stdin
$ cat <<EOF | kubectl create -f -
@ -61,68 +94,181 @@ data:
username: $(echo "jane" | base64)
EOF
# TODO: kubectl-explain example
```
## Viewing, Finding Resources
```shell
# Columnar output
```console
# Get commands with basic 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
$ kubectl get deployment my-dep # List a particular deployment
# 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
# Describe commands with verbose output
$ kubectl describe nodes my-node
$ kubectl describe pods my-pod
# List Services Sorted by Name
$ kubectl get services --sort-by=.metadata.name
$ kubectl get services --sort-by=.metadata.name # List Services Sorted by 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}'
$ 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})
$ echo $pods
$ sel=${$(kubectl get rc my-rc --output=json | jq -j '.spec.selector | to_entries | .[] | "\(.key)=\(.value),"')%?}
$ echo $(kubectl get pods --selector=$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"
$ JSONPATH='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}' \
&& kubectl get nodes -o jsonpath=$JSONPATH | grep "Ready=True"
```
## Modifying and Deleting Resources
## Updating Resources
```shell
$ 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
```console
$ kubectl rolling-update frontend-v1 -f frontend-v2.json # Rolling update pods of frontend-v1
$ kubectl rolling-update frontend-v1 frontend-v2 --image=image:v2 # Change the name of the resource and update the image
$ kubectl rolling-update frontend --image=image:v2 # Update the pods image of frontend
$ kubectl rolling-update frontend-v1 frontend-v2 --rollback # Abort existing rollout in progress
$ cat pod.json | kubectl replace -f - # Replace a pod based on the JSON passed into stdin
# TODO: examples of kubectl edit, patch, delete, replace, scale, and rolling-update commands.
# Force replace, delete and then re-create the resource. Will cause a service outage.
$ kubectl replace --force -f ./pod.json
# Create a service for a replicated nginx, which serves on port 80 and connects to the containers on port 8000
$ kubectl expose rc nginx --port=80 --target-port=8000
# Update a single-container pod's image version (tag) to v4
$ kubectl get pod mypod -o yaml | sed 's/\(image: myimage\):.*$/\1:v4/' | kubectl replace -f -
$ kubectl label pods my-pod new-label=awesome # Add a Label
$ kubectl annotate pods my-pod icon-url=http://goo.gl/XXBTWq # Add an annotation
$ kubectl autoscale deployment foo --min=2 --max=10 # Auto scale a deployment "foo"
```
## Patching Resources
Patch a resource(s) with a strategic merge patch.
```console
$ kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}' # Partially update a node
# Update a container's image; spec.containers[*].name is required because it's a merge key
$ kubectl patch pod valid-pod -p '{"spec":{"containers":[{"name":"kubernetes-serve-hostname","image":"new image"}]}}'
# Update a container's image using a json patch with positional arrays
$ kubectl patch pod valid-pod --type='json' -p='[{"op": "replace", "path": "/spec/containers/0/image", "value":"new image"}]'
```
## Editing Resources
The edit any API resource in an editor.
```console
$ kubectl edit svc/docker-registry # Edit the service named docker-registry
$ KUBE_EDITOR="nano" kubectl edit svc/docker-registry # Use an alternative editor
```
## Scaling Resources
```console
$ kubectl scale --replicas=3 rs/foo # Scale a replicaset named 'foo' to
$ kubectl scale --replicas=3 -f foo.yaml # Scale a resource specified in "foo.yaml" to 3
$ kubectl scale --current-replicas=2 --replicas=3 deployment/mysql # If the deployment named mysql's current size is 2, scale mysql to 3
$ kubectl scale --replicas=5 rc/foo rc/bar rc/baz # Scale multiple replication controllers
```
## Deleting Resources
```console
$ kubectl delete -f ./pod.json # Delete a pod using the type and name specified in pod.json
$ kubectl delete pod,service baz foo # Delete pods and services with same names "baz" and "foo"
$ kubectl delete pods,services -l name=myLabel # Delete pods and services with label name=myLabel
$ kubectl -n my-ns delete po,svc --all # Delete all pods and services in namespace my-ns
```
## Interacting with running Pods
```shell
$ 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)
```console
$ kubectl logs my-pod # dump pod logs (stdout)
$ kubectl logs -f my-pod # stream pod logs (stdout)
$ kubectl run -i --tty busybox --image=busybox -- sh # Run pod as interactive shell
$ kubectl attach my-pod -i # Attach to Running Container
$ kubectl port-forward my-pod 5000 6000 # Forward port 6000 of Pod to your to 5000 on your local machine
$ kubectl port-forward my-svc 6000 # Forward port to service
$ kubectl exec my-pod -- ls / # Run command in existing pod (1 container case)
$ kubectl exec my-pod -c my-container -- ls / # Run command in existing pod (multi-container case)
$ kubectl top pod POD_NAME --containers # Show metrics for a given pod and its containers
```
## Interacting with Nodes and Cluster
```console
$ kubectl cordon my-node # Mark my-node as unschedulable
$ kubectl drain my-node # Drain my-node in preparation for maintenance
$ kubectl uncordon my-node # Mark my-node as schedulable
$ kubectl top node my-node # Show metrics for a given node
$ kubectl cluster-info # Display addresses of the master and services
$ kubectl cluster-info dump # Dump current cluster state to stdout
$ kubectl cluster-info dump --output-directory=/path/to/cluster-state # Dump current cluster state to /path/to/cluster-state
# If a taint with that key and effect already exists, its value is replaced as specified.
$ kubectl taint nodes foo dedicated=special-user:NoSchedule
```
## Resource types
The following table includes a list of all the supported resource types and their abbreviated aliases.
Resource type | Abbreviated alias
-------------------- | --------------------
`clusters` |
`componentstatuses` |`cs`
`configmaps` |`cm`
`daemonsets` |`ds`
`deployments` |`deploy`
`endpoints` |`ep`
`event` |`ev`
`horizontalpodautoscalers` |`hpa`
`ingresses` |`ing`
`jobs` |
`limitranges` |`limits`
`namespaces` |`ns`
`networkpolicies` |
`nodes` |`no`
`petset` |
`persistentvolumeclaims` |`pvc`
`persistentvolumes` |`pv`
`pods` |`po`
`podsecuritypolicies` |`psp`
`podtemplates` |
`replicasets` |`rs`
`replicationcontrollers` |`rc`
`resourcequotas` |`quota`
`scheduledjob` |
`secrets` |
`serviceaccount` |`sa`
`services` |`svc`
`storageclasses` |
`thirdpartyresources` |
### Formatting output
To output details to your terminal window in a specific format, you can add either the `-o` or `-output` flags to a supported `kubectl` command.
Output format | Description
--------------| -----------
`-o=custom-columns=<spec>` | Print a table using a comma separated list of custom columns
`-o=custom-columns-file=<filename>` | Print a table using the custom columns template in the `<filename>` file
`-o=json` | Output a JSON formatted API object
`-o=jsonpath=<template>` | Print the fields defined in a [jsonpath](/docs/user-guide/jsonpath) expression
`-o=jsonpath-file=<filename>` | Print the fields defined by the [jsonpath](/docs/user-guide/jsonpath) expression in the `<filename>` file
`-o=name` | Print only the resource name and nothing else
`-o=wide` | Output in the plain-text format with any additional information, and for pods, the node name is included
`-o=yaml` | Output a YAML formatted API object