Hey guys, I was happily running 44 docker containers for a while on Debian host. Today I tried to add a new service (uptime-kuma) using portainer stacks, but I got this error:
Error response from daemon: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network
Quick google led me to this link where I found possible problem with max number of docker networks. I did docker network prune, it removed 5 networks that were not in use and viola, uptime-kuma is working now!
Am I reaching the limit? What to do if I need 10 more services on the same host? I bet I saw some people in this community running many more services
Docker network pools are huge by default. I had to change this as well.
This article covers the issue and the solution in detail:
https://straz.to/2021-09-08-docker-address-pools/
If you just want the solution, skip to the section titled How to configure docker to allow >500 bridge networks. I think you’ll need to remake all your networks after making the change, if I remember correctly.
Here’s my config now:
$ sudo cat /etc/docker/daemon.json { "default-address-pools": [ { "base":"172.16.0.0/12", "size":24 }, { "base":"172.17.0.0/12", "size":24 }, { "base":"172.18.0.0/12", "size":24 }, { "base":"172.19.0.0/12", "size":24 }, { "base":"172.20.0.0/12", "size":24 }, { "base":"172.21.0.0/12", "size":24 }, { "base":"172.22.0.0/12", "size":24 }, { "base":"172.23.0.0/12", "size":24 }, { "base":"172.24.0.0/12", "size":24 }, { "base":"172.25.0.0/12", "size":24 }, { "base":"172.26.0.0/12", "size":24 }, { "base":"172.27.0.0/12", "size":24 }, { "base":"172.28.0.0/12", "size":24 }, { "base":"172.29.0.0/12", "size":24 }, { "base":"172.30.0.0/12", "size":24 }, { "base":"172.31.0.0/12", "size":24 } ], "log-opts": { "max-size": "1g" } }I’m pretty sure all of those entries are in the same /12 network - 172.16.0.0/12. Apparently there’s nothing wrong with it, but I think you can significantly simplify that config by just removing all the extra ones
Could simplify it by making a 28 block at most. That is 14 IPs per bridge which seems like way more than one would generally need anyhow.
{ "default-address-pools": [ { "base":"172.16.0.0/12", "size":28 }, ] }Had to do exactly that last week when I hit Docker’s rather low network limit.
Good point!
Thx, Ill read that, it looks promising