Tutorial: Dockerize a node HTTP Server

Step-by-step tutorial for bringing traditional app into Docker world, but leave some questions and tips for brainstorming :-)

Prerequisites

• Docker-CE 20.10+

Follow the steps

Step 1: Prepare a simple app

$ vim httpServer.js

Step 2: Execute the app locally

$ node httpServer.js

Step 3: Search sutible official image

Docker Hub

if possible, try to use official image, but not to create customized one

Step 4: Execute the app with Docker

$ docker run --privileged -d \
    -v $(pwd):/opt/app:ro    \
    -w /opt/app              \
    -p 8080                  \
    node:18-alpine           \
      node httpServer.js

Question: how do I expose 8080 to world?

Step 5: Dockerize the app with Dockerfile

$ cat Dockerfile

$ docker build -t http_server_image .

Question: what will happen if I change the file httpServer.js?

Step 6: Execute the app via customized image

$ docker run -d -p 8080 http_server_image

Question: how do I check the console log while it is running as daemon?

Step 7: Define app with docker-compose

$ cat docker-compose.yaml

$ docker compose down && docker compose up

Question: when to use down command?

Step 8: Try to modify the app

$ vim httpServer.js

$ docker compose up

Question: why is the app not updated?

Step 9: Increase capacity with "scale"

$ docker compose scale web=2

Question: why this command will failed? how to achieve the scaling goal?

Step 10: Setup load balancer after application scaled

Question: how to setup load balancer to share loading across all the web service?

Step 11: Connected the app with database

Question: hot to setup database connection between web service and database?

Reference

• Dockerfile Reference

License

GPLv2