Docker v29+ Unspecified

docker-compose.yaml

# Requires Docker v29+ which supports defining network subnets as unspecified
# with a concrete subnet size. The Docker demon then will allocate these
# subnets efficiently from its default address pools.
#
# When using the default "bridge" network driver, the unspecified subnets
# must be or size /29 or larger, because the bridge always gets allocated
# an IP address.
#
# Best checked using Edgeshark, https://github.com/siemens/edgeshark
services:
    foo-a:
        image: busybox
        init: true
        entrypoint:
            - /bin/sh
            - -c
            - while true; do sleep 1; done
        networks:
            - foonet
    foo-b:
        image: busybox
        init: true
        entrypoint:
            - /bin/sh
            - -c
            - while true; do sleep 1; done
        networks:
            - foonet
    bar-a:
        image: busybox
        init: true
        entrypoint:
            - /bin/sh
            - -c
            - while true; do sleep 1; done
        networks:
            - barnet
    bar-b:
        image: busybox
        init: true
        entrypoint:
            - /bin/sh
            - -c
            - while true; do sleep 1; done
        networks:
            - barnet

networks:
    foonet:
        ipam:
            driver: default
            config:
                - subnet: 0.0.0.0/29
        internal: true
    barnet:
        ipam:
            driver: default
            config:
                - subnet: 0.0.0.0/29
        internal: true