DevOps Classroom notes 27/Jun/2026

How to write manifest files

ApiVersioning

• k8s api server exposes k8s Workloads as Resources
• K8s maintains api Versions for them
• K8s has api Versioning scheme Refer Here
• API Versioning:
  • alpha: v1alpha
  • beta: v1beta
  • stable: v1 or v2
• K8s groups multiple resources into api Groups

apiVersion: <group>/<version>

# if the group name is core write version directly

• Example:
  • group: core
  • Resource: Pod
  • version: v1

apiVersion: v1
kind: Pod

• Example 2:
  • group: apps
  • version: v1
  • Resource: Deployment

apiVersion: apps/v1
kind: Deployment

• Lets write first two fields of multiple resources using k8s 1.35 api reference
• Namespace

apiVersion: v1
kind: Namespace

• PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim

• Statefulset

apiVersion: apps/v1
kind: StatefulSet

metadata

• This contains information about the object which we are going to create
• on major note we will fill
  • name
  • labels
  • annonatations
• For today lets focus only on names

Example 1

• Lets write a spec for a pod with name example-1

apiVersion: v1
kind: Pod
metadata:
  name: example-1

• Lets create a deployment with a name deploy-1

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-1

Spec

• This is field for around 95 % of what we do
• This is where we provide our desired state
• To fill this field we need to understand the functionality

Status

• This is filled by k8s not by use

Pod in k8s

• Pod has container(s)

Filling pod specs

Example 1

• Lets write a manifest for k8s pod which has a httpd image based container

---
apiVersion: v1
kind: Pod
metadata:
  name: example-1
spec:
  containers:
    - image: httpd
      name: web 

• To create pod

kubectl apply -f <filepath>

• To delete the pod

kubectl delete -f <filepath>

• To view the pods

kubectl get pods

• To get more info on pods

kubectl get pods -o wide

• To get detailed info

kubectl describe pod <name>

• Commands:
  • apply
  • delete
  • describe
  • get
• In k8s what we create is referred as objects
• kubectl has interesting command

kubectl api-resources

• Exercise:
  • Write a spec to create a mysql container and pass environment variable for root password
  • Write a spec to create a nginx container and fill the port information.