Unable to start service matrix-synapse.service: Failed to start matrix-synapse.service

[ralfi]

Describe the bug
Today's update fails after just -u update and just install-all with message above

see here:

journalctl -xeu matrix-synapse.service tells me:

Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error running hook #0: error running hook: exit status 1, stdout: , stderr: failed to add interface vetha630877 to sandbox: error setting interface "vetha630877" IP to 172.23.0.2/16: cannot program address 172.23.0.2/16 in sandbox interface because it conflicts with existing route {Ifindex: 7576 Dst: 0.0.0.0/0 Src: <nil> Gw: 172.19.0.1 Flags: [] Table: 254 Realm: 0}: unknown

It seems to me this error is related to docker and/or iptables.

Additional context
How can i debug this?

[ralfi]

just stop-all tells me:

[ralfi]

But i am also never modify anything related to valkey... only modified to little-federation-helper in my vars.yml

[ralfi]

Mmmh, all other docker container works on my server (nextcloud and many others...) but this is only related to matrix-synapse.service.

I found this:
https://unix.stackexchange.com/questions/712659/what-does-it-means-when-the-docker-daemon-failed-to-add-an-interface-to-sandbox
https://stackoverflow.com/questions/74481450/failed-to-add-interface-to-sandbox

[ralfi]

[ralfi]

Grrrrh, since long time everything works but now every time i try it fails to start my homeserver on the same point...

[rcurtin]

I encountered this too today. I am not sure of your setup, but for me this had to do with the Debian upgrade of docker from version 26.1.5+dfsg1-4 to version 26.1.5+dfsg1-4+b1. I still had the older .debs sitting around in /var/cache/apt/archives/ so I just installed them with dpkg -i docker-cli-... docker.io-... runc-... containerd-... (add the version numbers of what you've got for those).

I'm assuming there was some policy change inside of Docker or something that hasn't found its way to this project yet. I'm not going to dig further and plan to just hide from the problem and not upgrade docker for a few months and hope someone solves the issue in the interim. :)

[spantaleev]

Sounds like Debian folks broke the Docker package somehow, or you need to do a full reboot to make it work again.

As far as I know, the playbook is not doing anything strange when starting containers, so I'm inclined to think of all such issues as a regression either in Docker or in the way it's packaged.

[ralfi]

@spantaleev @rcurtin
Thank you very much, i will try to investigate further. Full reboot do not work for me.

[ralfi]

@rcurtin Can you upload the deb's without the +b1 extension or share? Or can i find this on debian mirrors? I also have my own filetransfer server based on firefox send...

[ralfi]

@rcurtin found the related deb's

[ralfi]

can confirm, works again with the deb's without the name extension +b1, strange...

[comradeferret]

I had this issue too. I was on trixie, and just uninstalling docker and changing my apt sources back to bookworm before reinstalling docker did the trick. Unfortunately rolling back using cached packages did not, as I didn't have a cached version of runc and didn't know where to find one elsewhere.

[ralfi]

@comradeferret Do you look at snapshot.debian.org or debian archive?

[comradeferret]

@ralfi I didn't, but I'll know for next time, thanks! I don't use Debian often, just for this server, so I'm not the most knowledgeable.