Pods

A Kubernets pod is the smallest and simplest deployable unit.

A pod represents a single instance of a running process in your cluster and can contain one or more containers that share the same network namespace and storage resources.

Run Docker's "Hello World" on Kubernetes

Docker images can run in Kubernetes as pods, the following command runs the hello-world image from Docker's Hub in Kubernetes.

This image runs its process which outputs text to the stdout and then exits with success code.

The --restart parameter specifies that after exiting the program should not rerun.

The --image parameter specifies the name of the image to pull.

The -it paremeter sets two options:

• i: Interactive, allows to interact with stdin.
• t: The tty option allocates a pseudo-terminal for interactive sessions.

With -it we can see the output in the terminal.

kubectl run hello-world \
    --restart=Never \
    --image=hello-world \
    -it

Process Logs

In regular use cases, the -it option is not likely to be used, instead output is kept in the runtime context for the pod.

The logs subcommand can be used to check on hello-world pod logs.

kubectl logs hello-world

List Pods

kubectl get pod

The command will list every cluster pods.

NAME                    READY   STATUS      RESTARTS      AGE
hello-world

Inspect on Pod Details

Retrieve more details on a pod using the describe pod subcommand.

kubectl describe pod hello-world

Delete Pod

Once a pod is no longer needed, it can be deleted with pod delete subcommand.

kubectl delete pod hello-world

Inspect on Pod's using k9s

k9s will list Pods available in the Cluster.

Logs for the pod can be seen using the k9s interface.