SoFunction
Updated on 2025-04-11

How to define a bridge network and configure an IP address pool for the docker-compose

docker-compose defines a bridge network and configures an IP address pool for the network

If you want to define a bridge network in Docker Compose and configure an IP address pool for the network so that the service automatically assigns IP addresses from it,

You can follow the steps below

  1. Define the network and specify a subnet range.
  2. Set the gateway address.
  3. Enable the function of automatically assigning IP addresses.

Here is an exampleFile, showing how to define a bridged network containing an IP address pool:

version: '3.9'
services:
  web:
    image: nginx:latest
    networks:
      - my-bridge-network

  db:
    image: postgres:latest
    networks:
      - my-bridge-network

networks:
  my-bridge-network:
    driver: bridge
    ipam:
      config:
        - subnet: 172.20.0.0/16
          gateway: 172.20.0.1

explain

Network definition (networks):

  • my-bridge-network: Define a namemy-bridge-networkbridge network.
  • driver: bridge: Specify that the network type is bridged.
  • ipam: Defines the IP address manager.
  • config: Configure subnet and gateway information.
    • subnet: Set the network subnet range, here is172.20.0.0/16。
    • gateway: Set the gateway address of the network, here is172.20.0.1。

Service definition (services):

  • web: Use Nginx mirroring.
  • db: Use Postgres mirroring.
  • networks: Every service has been addedmy-bridge-networknetwork.

When Docker Compose starts a service, it automatically assigns an unused IP address to each service from the defined subnet range.

This means that the service will get a dynamically assigned IP address, rather than a fixed IP address.

Things to note

  • Make sure that the IP address assigned to the service is within the defined subnet range.
  • If you need more services or different subnets, please extend the configuration accordingly.
  • When the service starts, Docker Compose automatically selects the available IP address from the defined subnet to assign to the service.
  • Make sure that the selected subnet does not overlap with the existing network to avoid conflict.

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.