This is a quick-start tutorial for Docker using a node express web-server.
Project comes with a minimal setup for express, running a hello world webserver exposed on port 8000.
Run project by running npm start.
Project comes with a minimal docker setup.
The Dockerfile specifies the setup of the image, containing installation of required modules,
adding of the project files and running of the app.
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To install
dockerand the later useddocker-composewhen using mac, the most straight forward way is installing Docker Desktop. It comes with a useful GUI to control docker preferences. -
❯ docker build -t node-quickstart . Sending build context to Docker daemon 135.2kB Step 1/5 : FROM node:14 ---> a511eb5c14ec Step 2/5 : COPY package*.json ./ ---> f813b94104f8 Step 3/5 : RUN npm install ---> Running in 688a5686e89d added 50 packages from 37 contributors and audited 126 packages in 1.734s found 0 vulnerabilities Removing intermediate container 688a5686e89d ---> 1f518419cd22 Step 4/5 : COPY ./ ./ ---> 11802f3b0e25 Step 5/5 : CMD ["npm", "start"] ---> Running in 80e3bd397021 Removing intermediate container 80e3bd397021 ---> c65b8a5c0c55 Successfully built c65b8a5c0c55 Successfully tagged node-quickstart:latest
-tspecifies the tag of the image and can be freely chosen. -
❯ docker run node-quickstart 19:12:49 > docker-node-quickstart@1.0.0 start / > node app.js Example app listening at http://localhost:8000
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You will see the app start up just like being started without using docker. However, when accessing the server, you will receive a
Connection Refuseerror.❯ curl http://localhost:8000 curl: (7) Failed to connect to localhost port 8000: Connection refused
This is because currently the app is running on the docker container localhost and is not exposed to the host machine yet.
To expose a port from inside the container to the host machine, start the container with:❯ docker run -p 8000:8000 node-quickstart.v1 19:13:06 > docker-node-quickstart@1.0.0 start / > node app.js Example app listening at http://localhost:8000
Now the host local port
8000will redirect to the docker container port8000and accessing
http://localhost:8000will now succeed.❯ curl http://localhost:8000 Hello World!
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❯ docker run -p 8000:8000 -d --name node node-quickstart 18:21:48 c1bbff027182c57a1e8869dd5a3fe783f633fee6da7360987deca4d58f379ae9
The
--nameflag lets you assign a name to the container, which lets you easily reference it with docker commands. -
stopped / exited containers will not show
❯ docker ps 18:28:06 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c944e5e2f8ef node-quickstart "docker-entrypoint.s…" About a minute ago Up About a minute 0.0.0.0:8000->8000/tcp node
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❯ docker stop node 18:29:12 node
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❯ docker ps -a 18:29:52 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c944e5e2f8ef node-quickstart "docker-entrypoint.s…" 2 minutes ago Exited (0) 24 seconds ago node -
❯ docker rm node 18:30:16 node
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❯ docker run -p 8000:8000 -d --name node node-quickstart 5f3395d687558c0c2cffd61bf0d1f519b7902de64eb07e8daa7ed2090084e044 ❯ docker exec -it node /bin/bash 18:34:06 root@9828c2358b52:/# ls Dockerfile LICENSE README.md app.js bin boot dev etc home lib lib64 media mnt node_modules opt package-lock.json package.json proc root run sbin srv sys tmp usr var root@9828c2358b52:/#
This provides you with the foundational commands to run your current project containerized.
- Quick-start article covering the idea's and inner workings of docker
- Reference for the
Dockerfileconfiguration - Additional docker commands
You might notice that managing multiple containers, for let's say your frontend and backend will become painful.
I.e. you would have to build the image for frontend and backend and run the containers separately.
Fear not, docker-compose is here for the rescue 🎉🎉.
Docker-compose is taking care of building your images and running and configuring your containers.
It provides and yaml based configuration to programmatically define the behaviour of your containers
and replaces the need to use standalone docker commands all-together.
The project comes with a basic docker-compose.yml configuration to start our web-server.
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❯ docker-compose up 19:05:01 Starting node-2 ... done Starting node ... done Attaching to node, node-2 node | node | > docker-node-quickstart@1.0.0 start / node | > node app.js node | node-2 | node-2 | > docker-node-quickstart@1.0.0 start / node-2 | > node app.js node-2 | node | Example app listening at http://localhost:8000 node-2 | Example app listening at http://localhost:8000
You will notice that two containers started, without the need to specify any arguments.
Additionally, docker-compose will build any images that are not already built.
Both express servers are exposed to the host following the configuration (on port 8000 and port 9000)❯ curl http://localhost:8000 19:54:37 Hello World! ❯ curl http://localhost:9000 19:54:48 Hello World!
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❯ docker-compose up -d 19:41:36 Creating node-2 ... done Creating node ... done
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❯ docker-compose ps 19:41:56 Name Command State Ports ------------------------------------------------------------------------ node docker-entrypoint.sh npm start Up 0.0.0.0:8000->8000/tcp node-2 docker-entrypoint.sh npm start Up 0.0.0.0:9000->8000/tcp
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❯ docker-compose stop 19:42:08 Stopping node ... done Stopping node-2 ... done
- Reference for the
docker-compose.ymlconfiguration - Additional docker-compose commands
This quick-start does not cover docker volumes.
What are volumes?
Volumes let you share data with your containers and give you the possibility to persist data created inside the container.