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Kubectl Commands

Configuration and context⚑

Add a new cluster to your kubeconf that supports basic auth⚑

kubectl config set-credentials {{ username }}/{{ cluster_dns }} --username={{ username }} --password={{ password }}

Create new context⚑

kubectl config set-context {{ context_name }} --user={{ username }} --namespace={{ namespace }}

Get current context⚑

kubectl config current-context

List contexts⚑

kubectl config get-contexts

Switch context⚑

kubectl config use-context {{ context_name }}

Creating objects⚑

Create Resource⚑

kubectl create -f {{ resource.definition.yaml | dir.where.yamls.live | url.to.yaml }} --record

Create a configmap from a file⚑

kubectl create configmap {{ configmap_name }} --from-file {{ path/to/file }}

Deleting resources⚑

Delete the pod using the type and name specified in a file⚑

kubectl delete -f {{ path_to_file }}

Delete pods and services by name⚑

kubectl delete pod,service {{ pod_names }} {{ service_names }}

Delete pods and services by label⚑

kubectl delete pod,services -l {{ label_name }}={{ label_value }}

Delete all pods and services in namespace⚑

kubectl -n {{ namespace_name }} delete po,svc --all

Delete all evicted pods⚑

while read i; do kubectl delete pod "$i"; done < <(kubectl get pods | grep -i evicted | sed 's/ .*//g')

Editing resources⚑

Edit a service⚑

kubectl edit svc/{{ service_name }}

Information gathering⚑

Get credentials⚑

Get credentials 

kubectl config view --minify

Deployments⚑

Restart pods without taking the service down⚑

kubectl rollout deployment {{ deployment_name }}

View status of deployments⚑

kubectl get deployments

Describe Deployments⚑

kubectl describe deployment {{ deployment_name }}

Get images of deployment⚑

kubectl get pods --selector=app={{ deployment_name }} -o json |\
jq '.items[] | .metadata.name + ": " + .spec.containers[0].image'

Nodes⚑

List all nodes⚑

kubectl get nodes

Check which nodes are ready⚑

JSONPATH='{range .items[*]}{@.metadata.name}:{range @.status.conditions[*]}{@.type}={@.status};{end}{end}' \
&& kubectl get nodes -o jsonpath=$JSONPATH | grep "Ready=True"

External IPs of all nodes⚑

kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'

Get exposed ports of node⚑

export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')

Pods⚑

List all pods in the current namespace⚑

kubectl get pods

List all pods in all namespaces⚑

kubectl get pods --all-namespaces

List all pods of a selected namespace⚑

kubectl get pods -n {{ namespace }}

List with more detail⚑

kubectl get pods -o wide

Get pods of a selected deployment⚑

kubectl get pods --selector="name={{ name }}"

Get pods of a given label⚑

kubectl get pods -l {{ label_name }}

Get pods by IP⚑

kubectl get pods -o wide
NAME                               READY     STATUS    RESTARTS   AGE       IP            NODE
alpine-3835730047-ggn2v            1/1       Running   0          5d        10.22.19.69   ip-10-35-80-221.ec2.internal

Sort pods by restart count⚑

kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

Describe Pods⚑

kubectl describe pods {{ pod_name }}

Get name of pod⚑

pod=$(kubectl get pod --selector={{ selector_label }}={{ selector_value }} -o jsonpath={.items..metadata.name})

List pods that belong to a particular RC⚑

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})

Show the remaining space of a persistent volume claim⚑

Either look it in Prometheus or run in the pod that has the PVC mounted:

kubectl -n <namespace> exec <pod-name> -- df -ah

You may need to use kubectl get pod <pod-name> -o yaml to know what volume is mounted where.

Services⚑

List services in namespace⚑

kubectl get services

List services sorted by name 

kubectl get services --sort-by=.metadata.name

Describe Services⚑

kubectl describe services {{ service_name }}
kubectl describe svc {{ service_name }}

Replication controller⚑

List all replication controller⚑

kubectl get rc

Secrets⚑

View status of secrets⚑

kubectl get secrets

Namespaces⚑

View namespaces⚑

kubectl get namespaces

Limits⚑

kubectl get limitrange

kubectl describe limitrange limits

Jobs and cronjobs⚑

Get cronjobs of a namespace⚑

kubectl get cronjobs -n {{ namespace }}

Get jobs of a namespace⚑

kubectl get jobs -n {{ namespace }}

You can then describe a specific job to get the pod it created.

kubectl describe job -n {{ namespace }} {{ job_name }}

And now you can see the evolution of the job with:

kubectl logs -n {{ namespace }} {{ pod_name }}

Interacting with nodes and cluster⚑

Mark node as unschedulable⚑

kubectl cordon {{ node_name }}

Mark node as schedulable⚑

kubectl uncordon {{ node_name }}

Drain node in preparation for maintenance⚑

kubectl drain {{ node_name }}

Show metrics of all node⚑

kubectl top node

Show metrics of a node⚑

kubectl top node {{ node_name }}

Display addresses of the master and servies⚑

kubectl cluster-info

Dump current cluster state to stdout⚑

kubectl cluster-info dump

Dump current cluster state to directory⚑

kubectl cluster-info dump --output-directory={{ path_to_directory }}

Interacting with pods⚑

Dump logs of pod⚑

kubectl logs {{ pod_name }}

Dump logs of pod and specified container⚑

kubectl logs {{ pod_name }} -c {{ container_name }}

Stream logs of pod⚑

kubectl logs -f {{ pod_name }}
kubectl logs -f {{ pod_name }} -c {{ container_name }}

Another option is to use the kubetail program.

Attach to running container⚑

kubectl attach {{ pod_name }} -i

Get a shell of a running container⚑

kubectl exec {{ pod_name }} -it bash

Get a debian container inside kubernetes⚑

kubectl run --generator=run-pod/v1 -i --tty debian --image=debian -- bash

Run a pod in a defined node⚑

Get the node hostnames with kubectl get nodes, then override the node with:

kubectl run mypod --image ubuntu:18.04 --overrides='{"apiVersion": "v1", "spec": {"nodeSelector": { "kubernetes.io/hostname": "my-node.internal" }}}' --command -- sleep 100000000000000

Get a root shell of a running container⚑

  1. Get the Node where the pod is and the docker ID 

    kubectl describe pod {{ pod_name }}

  2. SSH into the node 

    ssh {{ node }}

  3. Get into docker 

    docker exec -it -u root {{ docker_id }} bash

Forward port of pod to your local machine⚑

kubectl port-forward {{ pod_name }} {{ pod_port }}:{{ local_port }}

Expose port⚑

kubectl expose {{ deployment_name }} --type="{{ expose_type }}" --port {{ port_number }}

Where expose_type is one of: ['NodePort', 'ClusterIP', 'LoadBalancer', 'externalName']

Run command on existing pod⚑

kubectl exec {{ pod_name }} -- ls /
kubectl exec {{ pod_name }} -c {{ container_name }} -- ls /

Show metrics for a given pod and it's containers⚑

kubectl top pod {{ pod_name }} --containers

Extract file from pod⚑

kubectl cp {{ container_id }}:{{ path_to_file }} {{ path_to_local_file }}

Upload a file to a pod⚑

kubectl cp {{ path_to_local_file }} {{ container_id }}:{{ path_to_file }}

Scaling resources⚑

Scale a deployment with a specified size⚑

kubectl scale deployment {{ deployment_name }} --replicas {{ replicas_number }}

Scale a replicaset⚑

kubectl scale --replicas={{ replicas_number }} rs/{{ replicaset_name }}

Scale a resource specified in a file⚑

kubectl scale --replicas={{ replicas_number }} -f {{ path_to_yaml }}

Updating resources⚑

Deployment⚑

Modify the image of a deployment⚑

kubectl set image {{ deployment_name }} {{ label }}:{{ label_value }}
for example 
kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1

Or edit it by hand 

kubectl edit {{ deployment_name }}

Get the status of the rolling update⚑

kubectl rollout status {{ deployment_name }}

Get the history of the deployment⚑

kubectl rollout history deployment {{ deployment_name }}

To get more details of a selected revision: 

kubectl rollout history deployment {{ deployment_name }} --revision={{ revision_number }}

Get back to a specified revision⚑

To get to the last version 

kubectl rollout undo deployment {{ deployment_name }}

To go to a specific version 

kubectl rollout undo {{ deployment_name }} --to-revision={{ revision_number }}

Pods⚑

Rolling update of pods⚑

Is prefered to use the deployment rollout

kubectl rolling-update {{ pod_name }} -f {{ new_pod_definition_yaml }}

Change the name of the resource and update the image⚑

kubectl rolling-update {{ old_pod_name }} {{ new_pod_name }} --image=image:{{ new_pod_version }}

Abort existing rollout in progress⚑

kubectl rolling-update {{ old_pod_name }} {{ new_pod_name }} --rollback

Force replace, delete and then re-create the resource⚑

** Will cause a service outage **

kubectl replace --force -f {{ new_pod_yaml }}

Add a label⚑

kubectl label pods {{ pod_name }} new-label={{ new_label }}

Autoscale a deployment⚑

kubectl autoscale deployment {{ deployment_name }} --min={{ min_instances }} --max={{ max_instances }} [--cpu-percent={{ cpu_percent }}]

Copy resources between namespaces⚑

kubectl get rs,secrets -o json --namespace old | jq '.items[].metadata.namespace = "new"' | kubectl create-f -

Formatting output⚑

-o=custom-columns=<spec>

-o=custom-columns-file=<filename>

Output a JSON formatted API object⚑

-o=json

-o=jsonpath=<template>

-o=jsonpath-file=<filename>

-o=name

Output in the plain-text format with any additional information, and for pods, the node name is included⚑

-o=wide

Output a YAML formatted API object⚑

-o=yaml

References⚑