How to use command line tools to manage your Kubernetes cluster

Hey there, fellow Kubernetes enthusiasts! Are you ready to learn how to manage your clusters like a pro using command line tools? If so, you're in the right place. Today, we're going to explore how to use command line tools to manage your Kubernetes cluster.

But before we get started, let's make sure we're all on the same page. Kubernetes is a powerful open-source platform that automates the deployment, scaling, and management of containerized applications. It can be tricky to get the hang of, but once you do, it's a game-changer.

One way to manage your Kubernetes cluster is through the command line. Using the command line interface (CLI), you can interact with Kubernetes using a series of commands that allow you to manage your cluster from the comfort of your terminal. But which tools are the best to use? Let's take a look at some of the most popular options.

kubectl

The most popular and widely used command line tool for working with Kubernetes is kubectl. Developed by Google, kubectl is a powerful tool that allows you to interact with a Kubernetes cluster by running commands from the terminal.

To get started with kubectl, you need to have it installed on your machine. You can download it as a standalone binary for most operating systems from the Kubernetes release page. Once you've installed it, you'll need to connect to your cluster using the kubectl command.

$ kubectl config use-context <context-name>

Once you're connected, you can start running commands to manage your cluster. For example, you can create a new deployment with the following command:

$ kubectl create deployment nginx --image=nginx

This command creates a new deployment with the name nginx and pulls the nginx image from Docker Hub. You can check the status of the deployment with the following command:

$ kubectl get deployments

This command lists all the deployments in your cluster, along with their current status. If you want to see more details about a specific deployment, you can use the describe command:

$ kubectl describe deployment nginx

This command provides detailed information about the nginx deployment, including its current state, the pods it's running, the ReplicaSets associated with it, and more.

kubectl is a powerful tool, and there's a lot more you can do with it than what we've covered here. If you're interested in learning more, check out the official Kubernetes documentation.

k9s

If you're looking for a more interactive and user-friendly way to manage your Kubernetes cluster from the command line, k9s might be the tool for you. k9s is a terminal-based UI that allows you to easily navigate and manage your Kubernetes resources.

To get started with k9s, you'll need to install it on your machine. You can download the latest release from the k9s GitHub page. Once you've installed it, you can connect to your Kubernetes cluster by running the k9s command.

$ k9s

This command launches the k9s UI, which provides a real-time view of your cluster's resources. You can use the arrow keys to navigate through the different resources and press enter to view more details about each resource.

One of the great things about k9s is that it provides a more natural and intuitive way to manage your cluster than kubectl. For example, if you want to scale a deployment, you can simply highlight it in the k9s UI and press the + key to add more replicas.

+ Deployment nginx

This command increases the number of replicas for the nginx deployment by one. You can see the new replica count reflected in the UI.

k9s also provides features like search and filtering, which make it easier to find and manage specific resources in your cluster. If you're interested in learning more about k9s, check out the official documentation.

stern

When you're running containerized applications in Kubernetes, it's essential to be able to view and analyze their logs. That's where stern comes in. stern is a command line tool that allows you to easily tail the logs of multiple pods at once.

To get started with stern, you'll need to install it on your machine. You can download the latest release from the stern GitHub page. Once you've installed it, you can use the stern command to tail the logs of a specific pod.

$ stern <pod-name>

This command tails the logs of the specified pod in real-time. One of the great things about stern is that it can tail the logs of multiple pods at once, which makes it easier to keep track of what's happening in your cluster.

$ stern nginx-*  

This command tails the logs of all pods in the nginx deployment, which is useful if you want to monitor the logs of all instances of a particular application.

stern also provides some useful filtering and formatting options, which make it easier to find and analyze the logs you're interested in. If you're interested in learning more about stern, check out the official documentation.

kubectx and kubens

If you're working with multiple Kubernetes clusters or namespaces, it can be challenging to keep track of which one you're currently using. That's where kubectx and kubens come in. kubectx is a command line tool that allows you to switch between different Kubernetes contexts quickly, while kubens allows you to switch between different namespaces within a context.

To get started with kubectx and kubens, you'll need to install them on your machine. You can download the latest releases from the kubectx and kubens GitHub pages. Once you've installed them, you can use the kubectx command to switch between different Kubernetes contexts.

$ kubectx <context-name>

This command switches to the specified context. If you're working with multiple contexts, you can list them all with the kubectx command:

$ kubectx

This command lists all the available contexts on your machine. You can use the arrow keys to navigate through the list and press enter to switch to a specific context.

Similarly, you can use the kubens command to switch between different namespaces within a context.

$ kubens <namespace-name>

This command switches to the specified namespace. If you're working with multiple namespaces, you can list them all with the kubens command:

$ kubens

This command lists all the available namespaces within the current context. You can use the arrow keys to navigate through the list and press enter to switch to a specific namespace.

kubectx and kubens are simple tools, but they can save you a lot of time and confusion when working with multiple Kubernetes clusters and namespaces.

Wrapping up

And there you have it, folks. These are just a few of the many command line tools available for managing your Kubernetes cluster. Whether you're using kubectl to deploy new applications, k9s to navigate through your resources, or stern to tail your logs, there's a tool out there that can make your life easier.

If you're new to Kubernetes, it can be overwhelming at first. But with the right tools and some practice, you'll be managing your clusters like a pro in no time. Thanks for reading, and happy Kube-ing!

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