What you will learn
- Use bridge networks
- Link containers by name
- Publish ports
New to this? Start here
The basics, in plain English
Apps are rarely alone; a web app needs to reach its database. Docker networking lets containers find and talk to each other, and lets you expose a container to the outside world through a port.
- Network
- A private space where containers can reach each other by name.
- Publish a port
- Opening a container’s port to your computer so you can reach the app from a browser.
- Service discovery
- Containers finding each other by name instead of by changing IP addresses.
- Host
- The actual machine running the containers.
- Mapping ( 8080:80 )
- Connecting a port on your machine (8080) to a port inside the container (80).
01
Networks
Containers on the same user-defined bridge network reach each other by name. -p publishes a container port to the host.
Try it yourself
bash
$docker network create app↳Create a private network so containers can talk by name.$docker run --network app --name db postgres↳Start the database, reachable on the network as “db”.$docker run --network app -p 8080:80 web↳Start the web app and expose port 80 as 8080 on your host.↳ lines explain what each command does — only the commands get copied
Finished this topic?
Mark it done to earn 100 XP and keep your streak alive.