09_Deployment_Lab

K8s | Deployment Lab

Problem Statement:-

In this lab we will deploy a few of our microservices in the Kubernetes cluster using Kubernetes Deployment:

• MySQL
• Attendance
• Gateway
• Frontend
• Webserver

By the end of this lab, you should be able to have these individual MS up and running.

What you will not have is the persistence of your MySQL database i.e. if your MySQL pod is restarted you will lose complete data.

Deleting Old Replica sets

Before going to the deployment we have to clean up the old replica sets.

kubectl delete rs empms-db empms-attendance empms-gateway empms-frontend empms-webserver

Deployments

MySQL Deployment

Create a MySQL Deployment manifest with name mysql-deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-db
  name: empms-db
spec:
  replicas: 1
  selector:
    matchLabels:
      app: empms-db
  template:
    metadata:
      labels:
        app: empms-db
    spec:
      containers:
      - image: opstree/empms-db:1.0
        imagePullPolicy: Always
        name: empms-db
        env:
        - name: MYSQL_DATABASE
          value: attendancedb
        ports:
        - containerPort: 3306

Create a resource from this manifest.

kubectl apply -f mysql-deployment.yaml

Validate the service

kubectl get deployments
kubectl get pods

Attendance

Create an attendance Deployment manifest with name attendance-deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-attendance
  name: empms-attendance
spec:
  replicas: 1
  selector:
    matchLabels:
      app: empms-attendance
  template:
    metadata:
      labels:
        app: empms-attendance
    spec:
      containers:
      - image: opstree/empms-attendance:1.0
        imagePullPolicy: Always
        name: empms-attendance
        ports:
        - containerPort: 8081

Create a resource from this manifest.

kubectl apply -f attendance-deployment.yaml

Validate the service

kubectl get deployments
kubectl get pods

Gateway

Create a gateway Deployment manifest with name gateway-deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-gateway
  name: empms-gateway
spec:
  replicas: 1
  selector:
    matchLabels:
      app: empms-gateway
  template:
    metadata:
      labels:
        app: empms-gateway
    spec:
      containers:
      - image: opstree/empms-gateway:1.0
        imagePullPolicy: Always
        name: empms-gateway
        ports:
        - containerPort: 8080

Create a resource from this manifest.

kubectl apply -f gateway-deployment.yaml

Validate the service

kubectl get deployments
kubectl get pods

Frontend

Create a frontend Deployment manifest with name frontend-deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-frontend
  name: empms-frontend
spec:
  replicas: 1
  selector:
    matchLabels:
      app: empms-frontend
  template:
    metadata:
      labels:
        app: empms-frontend
    spec:
      containers:
      - image: opstree/empms-frontend:1.0
        imagePullPolicy: Always
        name: empms-frontend
        ports:
        - containerPort: 5000

Create a resource from this manifest.

kubectl apply -f frontend-deployment.yaml

Validate the service

kubectl get deployments
kubectl get pods

Webserver

Create a webserver Deployment manifest with name webserver-deployment.yaml

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-webserver
  name: empms-webserver
spec:
  replicas: 1
  selector:
    matchLabels:
      app: empms-webserver
  template:
    metadata:
      labels:
        app: empms-webserver
    spec:
      containers:
      - image: opstree/empms-webserver:1.0
        imagePullPolicy: Always
        name: empms-webserver
        ports:
        - containerPort: 80

Create a resource from this manifest.

kubectl apply -f webserver-deployment.yaml

Validate the service

kubectl get deployments
kubectl get pods

Attendance V2

So if you try to list the attendance from UI there will be a blank page, which means attendance listing functionality is not working. So we can update the deployment to use the version of the image.

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: empms-attendance
  name: empms-attendance
spec:
  replicas: 5
  selector:
    matchLabels:
      app: empms-attendance
  template:
    metadata:
      labels:
        app: empms-attendance
    spec:
      initContainers:
      - name: init-mysql
        image: opstree/empms-mysql-healthcheck:1.0
        imagePullPolicy: Always
        env:
        - name: MYSQL_USERNAME
          value: "root"
        - name: MYSQL_PASSWORD
          value: "password"
        - name: MYSQL_HOST
          value: "empms-db"
        - name: MYSQL_DATABASE
          value: "attendancedb"
        - name: SLEEP_INTERVAL
          value: "30"
      containers:
      # Changing the tag from 1.0 to 2.0
      - image: opstree/empms-attendance:2.0
        imagePullPolicy: Always
        name: empms-attendance
        ports:
        - containerPort: 8081

Update the deployment

kubectl apply -f attendance-deployment.yaml

Validate the deployment

kubectl get pods -w