Assigning Specific Subnets to Docker Containers via Compose

When using docker-compose, containers may encounter IP conflicts with the host's internal network, particularly if both use similar address renges like 192.x.x.x. To avoid such issues, you can define custom subnets for container networks in your YAML configuration.

In the example below, a custom bridge network is created with a specific subnet (172.28.0.0/16) to ensure no overlap with the host’s network:

version: '3.9'
services:
  coredns:
    image: coredns/coredns:1.10.0
    container_name: coredns
    ports:
      - 53:53/udp
    networks:
      mynetwork:
        ipv4_address: 172.28.0.4
    volumes:
      - ./coredns/hostsfile:/etc/coredns/hostsfile
      - ./coredns/Corefile:/Corefile

networks:
  mynetwork:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: 172.28.0.0/16
          gateway: 172.28.0.1

Another example demonstrates assigning an explicit IP address within a defined subnet:

version: '3'
services:
  myservice:
    image: <image>
    networks:
      mynetwork:
        ipv4_address: 192.168.0.2

networks:
  mynetwork:
    driver: bridge
    ipam:
      config:
        - subnet: 192.168.0.0/16

Creating Custom Networks with Specific Subnets

To assign a particular subnet when running containers manually, first create a custom network:

docker network create --subnet=172.18.0.0/16 shadownet

Then launch a container using that network:

docker run --net shadownet -p 6008:6008 registry.cn-hangzhou.aliyuncs.com/fastgpt_docker/m3e-large-api

Inspect the container to confirm it received an IP from the specified subnet:

docker inspect <container_id>

Using Comppose with Custom Subnets

The same network setup can be expressed in a docker-compose.yml file:

version: '3'
services:
  myservice:
    image: registry.cn-hangzhou.aliyuncs.com/fastgpt_docker/m3e-large-api
    ports:
      - 6008:6008
    networks:
      - shadownet

networks:
  shadownet:
    driver: bridge
    ipam:
      config:
        - subnet: 172.18.0.0/16

Before running this configurasion, remove any conflicting networks:

docker network rm shadownet

Launch the stack using:

docker-compose -f /path/to/subnet.yml up

Disabling Auto-Restart for Docker Containers

To prevent a container from restarting automatically, modify its restart policy:

docker update --restart=no <container_name_or_id>

Verify the change:

docker inspect -f '{{.HostConfig.RestartPolicy.Name}}' <container_name_or_id>