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Warmup: Fundamental kubectl Commands!

FYhiT-BWAAAA2FB

Welcome back! This warmup is designed to help you review some essential kubectl commands. Some experienced Kubernetes folks might find this elementary, but if you're new to Kubernetes, these are critical skills worth practicing!

Your goal is to understand and get hands-on practice with the following commands:

  • kubectl apply
  • kubectl get
  • kubectl describe
  • kubectl delete

Let's get to it! 🧑‍💻

Step 1: Verify the Pod Manifest

Our environment already has a pod manifest available. Before we start, let's review what the manifest looks like:

student@bchd~$ batcat ~/mycode/yaml/my_first_pod.yaml

You'll see something like this:

apiVersion: v1
kind: Pod
metadata:
  name: myfirstpod
spec:
  containers:
  - name: webster
    image: registry.gitlab.com/alta3/webby:latest

This manifest defines a pod named myfirstpod that runs a container using the image webby:latest.

Step 2: Apply the Pod Manifest

First, let's create (or update) the pod using the apply command. This will create the pod based on the manifest.

student@bchd~$ kubectl apply -f ~/mycode/yaml/my_first_pod.yaml

What if the pod is already running?

  • If you’ve already applied this manifest before, you might see something like this:

    pod/myfirstpod unchanged

    That’s okay! This means the pod is already running, and the manifest hasn’t changed.

Step 3: Get Basic Info About the Pod

Next, let's check the status of your pod using the get command. This will give you a quick overview of your pod's state.

student@bchd~$ kubectl get pods

You should see something like this:

NAME         READY   STATUS    RESTARTS   AGE
myfirstpod   1/1     Running   0          1m
  • STATUS: This tells you whether the pod is running, pending, or failed.
  • RESTARTS: Number of times the pod has restarted (due to failures, etc.).

Step 4: Describe the Pod in Detail

To see a detailed breakdown of what's happening with your pod, use the describe command.

student@bchd~$ kubectl describe pod myfirstpod

This will give you loads of info, including:

  • Pod events
  • Container statuses
  • Resource usage

Look for the Events section to see how Kubernetes is managing your pod.

Step 5: Get Pod Logs

To view the logs produced by the container inside your pod, use the logs command:

student@bchd~$ kubectl logs myfirstpod

This will display any output the container has generated. Super handy for debugging!

Step 6: Delete the Pod

Let’s clean up our environment by deleting the pod using the delete command:

student@bchd~$ kubectl delete pod myfirstpod

You should see something like:

pod "myfirstpod" deleted

This removes the pod, but don't worry—you can always reapply the manifest if you need to bring it back!

Bonus Commands!

Here are a couple of other useful commands you should practice:

Get All Resources in a Namespace:

student@bchd~$ kubectl get all

This shows all resources (pods, services, deployments, etc.) running in the current namespace.

Explain a Kubernetes Resource:

If you ever need a quick refresher on what a resource does, use explain!

student@bchd~$ kubectl explain pod

This will give you a summary of what a pod is and what fields you can define in its manifest.

Conclusion

Boom! 💥 You've just gone through the basics of working with kubectl. Whether you're applying, getting, describing, or deleting, mastering these commands is key to managing Kubernetes like a pro!