Managing Multiple Kubernetes Clusters

Summary

Wanted to notate some things I learned about Kubernetes clusters and how to switch between multiple. I manage a few either in “production” or within a lab environment. So I needed to confirm that I’m not setting things up on the wrong cluster.

Contexts

Contexts are mentioned regarding the connection to different clusters. Kind of like a connection string in MySQL or Postgres. Like the connection strings for MySQL and Postgres these would contain all of the necessary information to connect to a Kubernetes cluster. Stored in YAML format.

Contexts can be listed either by running a command or checking the ~/.kube/config to show what’s listed and I believe these contexts are appended to this file when you setup the configuration to administer another cluster.

You can read your current configuration by issuing the following command. Which will provide every cluster you connect to.

cat ~/.kube/config

Get Current Context

Can be useful to know which context you’re in currently. This can be done by using the current-context subcommand.

kubectl config current-context

This will output the current context; or current connected cluster. In this case we are in the minikube context.

minikube

Listing Contexts

To know what contexts are avaialable. It would probably be a good idea to list them. This can be done by issuing the following command.

kubectl config get-contexts

Below is a simplified version of the table this provides. This table will give us which context we’re currently in, the cluster name, the context name, cluster name, authorization info for the cluster, the namespace we’re working in for that cluster.

CURRENT   NAME            CLUSTER         AUTHINFO          NAMESPACE
          kuberneteslab   kuberneteslab   kuberneteslab
*         minikube        minikube        minikube          default

Changing Contexts

The next thing I would like to note is changing contexts.

kubectl config use-context kuberneteslab

This will output the following indicating that context was switched.

Switched to context "kuberneteslab".

In the event that you don’t trust the output; for whatever reason, you can check for it using the config current-context command.