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Mokhutso Manaswe
Mokhutso Manaswe

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Documentation on my success to deploy web application to a featured Kubernetes environment.

#docker #kubernetes #deploy

Prerequisites

  • Download and Install Docker
  • Download and install Docker desktop
  • IDE (Visual Studio Code)
  • Sign-up to Docker Hub
  • Install compose plugin

Get app

  • Cloned node.js todo wep app github

Build the app’s container image

  • In the app directory created a Dockerfile
  • Added the folowing content to the Dockerfile [image]
  • Build the container image docker build -t sca-project
  • Started the app container docker run -dp 3000:3000 sa-project
  • Opened web browser to localhost to see the app

localhost3000

Share application

  • Created docker repository [image] on Docker Hub docker-repo
  • Docker login -u my_username
  • docker tag sca-project my_username/sca-project
  • docker push my_username/sca-project

Persist the database

  • docker volume create todo-db
  • docker run -dp 3000:3000 –mount type-volume, src=todo-db,target=/etc/todos sa-project
  • Got to see my list being stored
  • docker volume inspect todo-db

Run app in a development container with a bind mount 

docker run -dp 3000:3000 \ -w /app --mount type=bind,src="$(pwd)",target=/app \ node:18-alpine \ sh -c "yarn install && yarn run dev"
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docker run -dp 3000:3000 ` -w /app --mount "type=bind,src=$pwd,target=/app" ` node:18-alpine ` sh -c "yarn install && yarn run dev"
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  • docker logs -f <container-id>
  • Make changes to app.js , save file (restarts the app inside the container automatically)
  • Refresh the pages and saw my changes being reflected almost immediately

Multi container apps

- docker network create todo-app 

docker run -d \ --network todo-app --network-alias mysql \ -v todo-mysql-data:/var/lib/mysql \ -e MYSQL_ROOT_PASSWORD=secret \ -e MYSQL_DATABASE=todos \ mysql:8.0
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  • docker exec -it <my-sql-container-id> myqsl -u root -p
  • Into mysql shell -> show databases; (don’t forget the semi-colons or else nothing will be displayed)
  • Exit the mysql shell

Connect mysql

- docker network create todo-app 

docker run -d ` --network todo-app --network-alias mysql ` -v todo-mysql-data:/var/lib/mysql ` -e MYSQL_ROOT_PASSWORD=secret ` -e MYSQL_DATABASE=todos ` mysql:8.0
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  • Docker logs -f <container-id>
  • docker exec -it <my-sql-container-id> myqsl -p todos

mysql

  • Into mysql shell -> select * from todos_items

  • Exit the mysql shell

    Docker compose

  • docker compose version

  • In the root folder created docker-compose.yml

  • Insert into docker-compose.yml file

services:
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Define the app service

  • docker-compose.yml file should look like: 
services: app: image: node:18-alpine command: sh -c "yarn install && yarn run dev" ports: - 3000:3000 working_dir: /app volumes: - ./:/app environment: MYSQL_HOST: mysql MYSQL_USER: root MYSQL_PASSWORD: secret MYSQL_DB: todos mysql: image: mysql:8.0 volumes: - todo-mysql-data:/var/lib/mysql environment: MYSQL_ROOT_PASSWORD: secret MYSQL_DATABASE: todos volumes: todo-mysql-data:
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Run the application stack

  • docker compose up -d

  • See the app stack in docker desktop dashboard

    Describe apps using kubernetes yaml

  • Create deployment.yaml in the app root folder

  • Fill deploment.yaml with this code

apiVersion: apps/v1 kind: Deployment metadata: name: bb-demo namespace: default spec: replicas: 1 selector: matchLabels: bb: web template: metadata: labels: bb: web spec: containers: - name: bb-site image: getting-started imagePullPolicy: Never --- apiVersion: v1 kind: Service metadata: name: bb-entrypoint namespace: default spec: type: NodePort selector: bb: web ports: - port: 3000 targetPort: 3000 nodePort: 30002
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Create and monitor deployment

  • Enabled Kubernetes on Docker Desktop setting
  • Kubectl apply -f deplyment.yaml
  • Kubectl rollout status deployment/app-deployment

deploy

  • Now can access the app with the yaml configuration nodePort :30002

30002

  • Kubectl get deployments -> view pods configured by yaml file]
  • Kubectl get pods
  • Kubectl get services
  • Kubectl describe deploments

monitor

Scale deployment

  • Kubectl scale deployment/app-deployment –replicas=3
  • Horizontal pod autoscaling
  • Kubectl autoscale deployment/app-deployment –min=3 –max–10 –cpu-percentage=80

scaling

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