Kubernetes Pods: An Introduction

What is a k8s pods?

A Kubernetes (k8s) pod is the smallest deployable unit in Kubernetes, which can contain one or more containers. Pods are used to manage and run applications within a Kubernetes cluster.

When you create a Deployment, Kubernetes creates a Pod to host your application instance. A Pod is a Kubernetes abstraction that represents a group of one or more application as containers and share resources for those containers.
These resources include:

• Shared storage, as Volumes.

• Networking, as a unique cluster IP address.

• Information about how to run each container, such as the container image version or ports to be used.

We can create Kubernetes (k8s) pods in two primary ways:

Imperative Method

In the imperative approach, you directly issue commands to create and manage Pods.

• Creating a Pod:

    kubectl run my-pod --image=nginx --restart=Never
  

  This command creates a Pod named "my-pod" using "nginx" image.

• Listing Pods:

    kubectl get pods
  

  This command displays all the Pods in the current namespace.

• Deleting a Pod:

    kubectl delete pod my-pod
  

  This command removes the specified Pod.

Declarative Method

In the declarative method, you define the desired state of your Pods in a YAML configuration file.

1. Create a Pod YAML file (pod.yaml):

    apiVersion: v1
    kind: Pod
    metadata:
      name: my-pod
    spec:
      containers:
      - name: my-container
        image: nginx
   

   The manifest (YAML): We will break the manifest down into four parts:

   • ApiVersion — Version of the Kubernetes API you’re using

   • Kind — Kind of object you want to create.

   • Metadata — Information that uniquely identifies the object, such as name or namespace.

   • Spec — Specified configuration of our pod, for example image name, container name, volumes, etc.

2. Applying the configuration:

    kubectl apply -f pod.yaml
   

   This command creates the Pod according to the specifications defined in the YAML file.

3. Viewing the Pod’s status:

    kubectl describe pod my-pod
   

   This provides detailed information about the Pod, including its status and events.

4. Deleting a Pod:

    kubectl delete -f pod.yaml
   

   This removes the Pod defined in the YAML configuration.

Key Concepts

• Pod: The smallest deployable unit in Kubernetes, typically encapsulating a single container.

• Imperative vs. Declarative: The imperative method involves command-based actions, while the declarative method relies on configuration files to manage resources.

• kubectl: The command-line tool used to interact with the Kubernetes API.

That’s a quick rundown of setting up a Kubernetes cluster, creating PODs using both imperative and declarative methods, and managing them with key commands. Kubernetes is all about managing containers at scale, and these approaches helped me gain a deeper understanding of POD management!

"I believe this article will be beneficial, allowing you to uncover fresh insights and gain enriching knowledge."

Happy Learning🙂

PARTH SHARMA