Tips and Tricks: K8S Context Commands

Thursday, Sep 23, 2021 16:00 · 437 words · 3 minutes read

Tips and Tricks

What is a K8S context?

Kubernetes context allows engineers to configure access to multiple clusters by using configuration files. It is a set of parameters, which describes K8S cluster, namespace and user, basically the information needed to access the K8S cluster and its resources. This information is stored on the filesystem within ~/.kube/config or ~/.kube/KUBECONFIG (by default), or defined across multiple configuration files.

...
contexts:
- context:
    cluster: dev-k8s
    namespace: apps
    user: clusterUser_dev-k8s
  name: clusterUser_dev-k8s

- context:
    cluster: minikube
    extensions:
    - extension:
        provider: minikube.sigs.k8s.io
        version: v1.21.0
      name: context_info
    namespace: default
    user: minikube
  name: minikube

current-context: dev-k8s
...

K8S context CLI commands

Display the merged K8S settings

kubectl config view

cat ~/.kube/config

Output:

...
contexts:
- context:
    cluster: dev-k8s
    namespace: apps
    user: clusterUser_dev-k8s
  name: clusterUser_dev-k8s

- context:
    cluster: minikube
    extensions:
    - extension:
        provider: minikube.sigs.k8s.io
        version: v1.21.0
      name: context_info
    namespace: default
    user: minikube
  name: minikube

current-context: dev-k8s
...

Display the current K8S context

kubectl config current-context

Output:

dev-k8s

List all K8S contexts

kubectl config get-contexts

Output:

*       dev-k8s            dev-k8s            clusterUser_dev-k8s                                apps
        minikube           minikube           minikube                                           default

Switch to a different K8S context

kubectl config use-context minikube

Output:

Switched to context "minikube".

Double check the current context

kubectl config get-contexts

Output:

        dev-k8s            dev-k8s            clusterUser_dev-k8s                                apps
*       minikube           minikube           minikube                                           default

Additional information

You could get more helpful information about the commands listed above or have a look at what else is available to do with the context by using:

kubectl config use-context --help

Output:

Sets the current-context in a kubeconfig file

Aliases:
use-context, use

Examples:
  # Use the context for the minikube cluster
  kubectl config use-context minikube

Usage:
  kubectl config use-context CONTEXT_NAME [options]

More kubectl config commands

kubectl config --help

Output:

Modify kubeconfig files using subcommands like "kubectl config set current-context my-context"

 ...

Available Commands:
  current-context Displays the current-context
  delete-cluster  Delete the specified cluster from the kubeconfig
  delete-context  Delete the specified context from the kubeconfig
  get-clusters    Display clusters defined in the kubeconfig
  get-contexts    Describe one or many contexts
  rename-context  Renames a context from the kubeconfig file.
  set             Sets an individual value in a kubeconfig file
  set-cluster     Sets a cluster entry in kubeconfig
  set-context     Sets a context entry in kubeconfig
  set-credentials Sets a user entry in kubeconfig
  unset           Unsets an individual value in a kubeconfig file
  use-context     Sets the current-context in a kubeconfig file
  view            Display merged kubeconfig settings or a specified kubeconfig file

Usage:
  kubectl config SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).