PODs with YAML

Welcome to this comprehensive guide where you'll learn how to define and manage a Kubernetes Pod using a YAML configuration file. Kubernetes relies on declarative YAML manifests to create and update resources such as Pods, Deployments, and Services. By the end of this tutorial, you'll understand the required fields, best practices for YAML structure, and how to deploy and inspect your Pod.

Table of Contents

1. Understanding the Top-Level Fields
2. Pod Definition Skeleton
3. Detailed Field Breakdown
4. Deploying Your Pod
5. Inspecting Your Pod
6. Summary
7. Links and References

Understanding the Top-Level Fields

Every Kubernetes manifest shares four mandatory top-level fields. These fields tell Kubernetes what to create, how to version it, and any additional identifying metadata or configuration details.

Pod Definition Skeleton

Start with the minimal skeleton for a Pod manifest:

apiVersion: v1
kind: Pod
metadata:
spec:

You’ll expand each section to specify your Pod’s name, labels, and container settings.

Detailed Field Breakdown

apiVersion

Defines the API group and version that Kubernetes will use to process this resource.
For Pods, it’s always:

apiVersion: v1

kind

Specifies the type of object to create. For this tutorial:

kind: Pod

Other common values include Deployment, Service, and ReplicaSet.

metadata

Contains identifying information such as the resource’s name and optional labels for grouping and selection.

metadata:
  name: myapp-pod
  labels:
    app: myapp
    tier: frontend

• name: A unique identifier for the Pod within its namespace.
• labels: Arbitrary key/value pairs for organizational or selection purposes.

spec

Defines the desired state. In a Pod, this means listing the containers it should run.

spec:
  containers:
    - name: nginx-container
      image: nginx:latest
      ports:
        - containerPort: 80

Key points:

• containers is a YAML list; you can define multiple containers per Pod.
• Each container requires at least a name and image.
• You can optionally define ports, environment variables, volume mounts, and more.

Deploying Your Pod

1. Save your manifest to pod-definition.yaml.
2. Run the following command to create the Pod:

kubectl create -f pod-definition.yaml

You should see:

pod/myapp-pod created

Inspecting Your Pod

List All Pods

kubectl get pods

Sample output:

NAME        READY   STATUS    RESTARTS   AGE
myapp-pod   1/1     Running   0          30s

Describe a Pod

To view detailed status and event logs:

kubectl describe pod myapp-pod

Key sections in the output include Labels, Containers, Conditions, and recent Events.

Summary

In this lesson, you learned how to:

1. Structure a basic Kubernetes Pod manifest with the required top-level fields.
2. Define metadata and container specifications in YAML.
3. Deploy your Pod using kubectl create.
4. Inspect status and logs with kubectl get and kubectl describe.

Up next, we’ll explore Deployments and how they automate pod scaling and updates.

Links and References

• Kubernetes Official Documentation
• Kubernetes API Concepts
• Kubectl Cheat Sheet