Kubectl is a set of commands for controlling Kubernetes clusters. Every Kubernetes command has an API endpoint, and kubectl’s primary purpose is to carry out HTTP requests to the API.
While it is possible to issue HTTP requests yourself (e.g., using curl), kubectl is designed to make this process more comfortable and straightforward.
This tutorial will cover all the common kubectl operations and provide examples to familiarize yourself with the syntax.
Note: For more information about Kubernetes installation, refer to How to Install Kubernetes on a Bare Metal Server
List of kubectl Commands
Use the kubectl commands in the sections below as a quick reference when working with Kubernetes.
To list one or more pods, replication controllers, services, or daemon sets, use the
<strong>kubectl get</strong> command.
Generate a plain-text list of all namespaces:
kubectl get namespaces
Generate a plain-text list of all pods:
kubectl get pods
Generate a detailed plain-text list of all pods, containing information such as node name:
kubectl get pods -o wide
Generate a list of all pods running on a particular node server:
kubectl get pods --field-selector=spec.nodeName=[server-name]
List a specific replication controller in plain-text:
kubectl get replicationcontroller [replication-controller-name]
Generate a plain-text list of all replication controllers and services:
kubectl get replicationcontroller,services
Generate a plain-text list of all daemon sets:
kubectl get daemonset
Creating a Resource
Create a resource such as a service, a deployment, a job, or a namespace using the
<strong>kubectl create</strong> command.
For example, to create a new namespace, type:
kubectl create namespace [namespace-name]
Create a resource from a JSON or YAML file:
kubectl create –f [filename]
Applying and Updating a Resource
To apply or update a resource use the
kubectl apply command. The source in this operation can be either a file or the standard input (stdin).
Create a new service with the definition contained in [service-name].yaml:
kubectl apply -f [service-name].yaml
Create a new replication controller with the definition contained in [controller-name].yaml:
kubectl apply -f [controller-name].yaml
Create the objects defined in any .yaml, .yml, or .json file in a directory:
kubectl apply -f [directory-name]
To update a resource by editing it in a text editor, use
kubectl edit. This command is a combination of the
<strong>kubectl get</strong> and
kubectl apply commands.
For example, to edit a service, type:
kubectl edit svc/[service-name]
This command opens the file in your default editor. To choose another editor, specify it in front of the command:
KUBE_EDITOR=”[editor-name]” kubectl edit svc/[service-name]
Displaying the State of Resources
To display the state of any number of resources in detail, use the
kubectl describe command. By default, the output also lists uninitialized resources.
View details about a particular node:
kubectl describe nodes [node-name]
View details about a particular pod:
kubectl describe pods [pod-name]
Display details about a pod whose name and type are listed in pod.json:
Kubectl describe –f pod.json
See details about all pods managed by a specific replication controller:
kubectl describe pods [replication-controller-name]
Show details about all pods:
kubectl describe pods
To remove resources from a file or stdin, use the
kubectl delete command.
Remove a pod using the name and type listed in pod.yaml:
kubectl delete -f pod.yaml
Remove all pods and services with a specific label:
kubectl delete pods,services -l [label-key]=[label-value]
Remove all pods (the command includes uninitialized pods as well):
kubectl delete pods --all
Executing a Command
kubectl exec to issue commands to a container or to open a shell in a container.
Receive output from a command run on the first container in a pod:
kubectl exec [pod-name] -- [command]
Get output from a command run on a specific container in a pod:
kubectl exec [pod-name] -c [container-name] -- [command]
Run /bin/bash from a specific pod. The received output comes from the first container:
kubectl exec -ti [pod-name] -- /bin/bash
Modifying kubeconfig Files
<strong>kubectl config</strong> command lets you view and modify kubeconfig files. This command is usually followed by another sub-command.
Display the current context:
kubectl config current-context
Set a cluster entry in kubeconfig:
kubectl config set-cluster [cluster-name] --server=[server-name]
Unset an entry in kubeconfig:
kubectl config unset [property-name]
Printing Container Logs
To print logs from containers in a pod, use the
kubectl logs command.
The syntax for printing logs is:
kubectl logs [pod-name]
To stream logs from a pod, use:
kubectl logs -f [pod-name]
Short Names for Resource Types
Some of the kubectl commands listed above may seem unwieldy due to their length. For this reason the names of common kubectl resource types also have shorter versions.
For example, consider the command mentioned above:
kubectl create namespace [namespace-name]
You can also write this command as:
kubectl create ns [namespace-name]
Here is the full list of kubectl short names:
|Short Name||Long Name|
kubectl Cheat Sheet
You can find all the commands listed in this article in the one-page reference sheet below. Download the kubectl Command PDF and save it for future use.
This tutorial provided you with the most common kubectl commands to help you manage your Kubernetes API. The accompanying cheat sheet enables you to have all the commands in one place, easily accessible for a quick reference.