Defining And Running Pods - Complete Kubernetes Pod YAML & Commands Guide

Comprehensive guide to defining and running Kubernetes Pods with detailed YAML configuration examples, essential kubectl commands, pod management techniques, and troubleshooting tips. Learn pod YAML structure, kubectl create commands, and best practices for pod deployment.

Kubernetes Pod YAML Explained

# YAML Configuration for a Kubernetes Pod
apiVersion: v1 # Kubernetes API version
kind: Pod # Type of Kubernetes resource
metadata:
    name: myapp-pod # Name of the pod
    labels:
        app: myapp # Label for application identification
        type: front-end # Label for type classification
spec:
    containers:
    - name: nginx-container # Name of the container
      image: nginx # Docker image to use
      ports:
      - containerPort: 80 # Port the container exposes
        name: http # Name for the port
        protocol: TCP # Protocol used
      env:
        - name: DBCON # Environment variable name
          value: connectionstring # Environment variable value
      command: ["/bin/sh", "-c"] # Command to run in the container
      args: ["echo ${DBCON}"] # Arguments for the command

YAML Components Explained

apiVersion

Specifies the Kubernetes API version. For Pods, this is typically "v1".

kind

Defines the type of resource. In this case, it's a "Pod".

metadata

Contains identifying information about the pod, including name and labels.

spec

The specification that describes the desired state of the pod.

containers

Defines the containers that will run inside the pod. A pod can contain multiple containers.

env

Sets environment variables for the container. In this example, DBCON is set to "connectionstring".

command and args

These override the default command and arguments of the container image. Similar to Docker's ENTRYPOINT and CMD.

Kubernetes Pod Commands Reference

Command Description Action
kubectl create -f [file] Create a pod from a YAML definition file
kubectl run [podname] --image=[image] Run a pod with a specific image
kubectl get pods List all running pods
kubectl get pods -o wide List pods with additional information
kubectl describe pod [podname] Show detailed information about a specific pod
kubectl get pod [podname] -o yaml Extract the pod definition in YAML format
kubectl exec -it [podname] -- [command] Execute a command inside a running pod
kubectl delete -f [file] Delete a pod using its definition file
kubectl delete pod [podname] Delete a pod by name

Usage Tips

YAML First

Prefer kubectl create -f or apply -f for repeatable deployments instead of manual kubectl run.

Debug Pods

Use kubectl describe and kubectl logs to troubleshoot failing pods quickly.