Docker "ERROR: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network"

Question

I've seen it suggested docker may be at its maximum of created networks. The command docker network prune can be used to remove all networks not used by at least one container.

My issue ended up being, as Robert commented about: an issue with openvpn service openvpn stop 'solved' the problem.

I ran into this problem because I had OpenVPN running. As soon as I killed OpenVPN, docker-compose up fired right up, and the error disappeared.

I ran in this problem with OpenVPN working as well and I've found a solution where you should NOT stop/start OpenVPN server.

Idea that You should specify what exactly subnet you want to use. In docker-compose.yml write:

networks:
  default:
    driver: bridge
    ipam:
      config:
        - subnet: 172.16.57.0/24

That's it. Now, default network will be used and if your VPN did not assign you something from 172.16.57.* subnet, you're fine.

Following Peter Hauge's comment, upon running docker network ls I saw (among other lines) the following:

NETWORK ID          NAME                                    DRIVER              SCOPE
dc6a83d13f44        bridge                                  bridge              local
ea98225c7754        docker_gwbridge                         bridge              local
107dcd8aa889        host                                    host                local

The line with NAME and DRIVER as both host seems to be what he is referring to with "networks already created on your host". So, following https://gist.github.com/bastman/5b57ddb3c11942094f8d0a97d461b430, I ran the command

docker network rm $(docker network ls | grep "bridge" | awk '/ / { print $1 }')

Now docker-compose up works (although newnym.py produces an error).

I have the same problem. I ran docker system prune -a --volumes, docker network prune, but neither helped me.

I use a VPN, I turned off the VPN and, after it docker started normal and was able to create a network. After that, you can enable VPN again.

TL;DR

Add

version: '3.7'
services:
  web:
    ...
    network_mode: bridge

Read about network_mode in the documentation.

Long version

Disclaimer: I am not very knowledgeable about Docker networking, but this did the trick for me. YMMV.

When I ran docker run my-image the networking gave me no problems, but when I converted this command to a docker-compose.yml file, I got the same error as the OP.

I read Arenim's answer and some other stuff on the internet that suggested to re-use an existing network.

You can find existing networks like this:

# docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
ca0415dfa442        bridge              bridge              local
78cbbda034dd        host                host                local
709f13f4ce2d        none                null                local

I wanted to reuse the default bridge network, so I added

services:
  web:
    ...

networks:
  default:
    external:
      name: bridge

to the the root of my docker-compose.yml (so not inside one of my services, but at the root indentation).

I now got the following error:

ERROR: for your-container network-scoped alias is supported only for containers in user defined networks

This led met to this Docker Github issue, that plainly stated that I should add the network_mode object to my docker-compose:

version: '3.7'
services:
  web:
    ...
    network_mode: bridge

This was tested on Docker version 18.09.8, docker-compose version 1.24.1 and the compose file format 3.7.