DevOps Classroom notes 02/Jul/2026

Deployments

• In Reality we have an application which we containerize
• we need to deploy this application
• I.e. when we get a newer version of application we need to delete and recreate replica sets
• in enterprise cases, we might need the following options
  • Capability to move to next version with minimum or no downtime
  • If the newer version is not working or having issues quickly rolling back to previous version.
• Refer Here for official docs
• Deployment strategies
  • recreate: will remove all older versions and recreates a new version
  • rollingUpdate: we can define
    • maxSurge: maximum number or percentage of pods which can be created beyond max number (default => 25%)
    • maxUnavailable: maximum number of pods or percentage that can be unavailable during deployment (default => 25%)

Experiment

• Lets create a deployment with 3 nginx pods (consider this version 1)
• Then we will simulate a newer release by changing the image to httpd
• note: i will use service here, which can be ignored by you for todays
• First version of yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ex1
  labels:
    app: web
    env: dev
spec:
  replicas: 4
  minReadySeconds: 5
  selector:
    matchLabels:
      app: web
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
  template:
    metadata:
      labels:
        app: web
        version: v1
    spec:
      containers:
        - image: nginx
          name: web
          ports:
            - containerPort: 80
              protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
  name: ex1-nodeport
spec:
  type: NodePort
  selector:
    app: web
  ports:
    - name: http
      protocol: TCP
      port: 80          # Service Port
      targetPort: 80    # Container Port
      nodePort: 30080   # NodePort (must be in the allowed range)   

• With deployments, daemeonsets and statefulsets we can use kubectl rollout
• Now execute rollout commands such as history and status
• Now make changes in the yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ex1
  labels:
    app: web
    env: dev
spec:
  replicas: 4
  minReadySeconds: 5
  selector:
    matchLabels:
      app: web
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
  template:
    metadata:
      labels:
        app: web
        version: v1.1
    spec:
      containers:
        - image: httpd
          name: web
          ports:
            - containerPort: 80
              protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
  name: ex1-nodeport
spec:
  type: NodePort
  selector:
    app: web
  ports:
    - name: http
      protocol: TCP
      port: 80          # Service Port
      targetPort: 80    # Container Port
      nodePort: 30080   # NodePort (must be in the allowed range)  

Phippy goes to zoo

• Refer Here for the story