Description

• re-raised from Error initializing Docker network controller: Conflict with existing bridge network docker0 docker/for-linux#1512
• originally reported by @poqdavid

I'm encountering an issue with Docker on my Linux server where the Docker daemon fails to start due to a network conflict involving the default docker0 bridge network. And I would appreciate it if anyone can help me figure out this problem.
Below are the details from the logs:

Dec 18 03:48:16 server dockerd[2720]: failed to start daemon: Error initializing network controller: error creating default "bridge" network: cannot create network e6df46e3462f284f46bb95fe8bdfa5530dfb1451b2859e886896fcecffe0f00a (docker0): conflicts with network 34958e77236c09db2c3cbe6198a3eb085736a648650638a1295480847abcf4b6 (docker0): networks have same bridge name

Here is the full log: docker_log1.log
Also my firewall log: firewalld_log1.log

Steps to Reproduce:

1. Start the Docker service on the affected system.
2. Observe that the daemon fails to start and the error above is logged.

Temporary Fix:
As a temporary workaround, I can resolve the issue by running the following commands:

rm -rf /var/lib/docker/network
systemctl restart docker

However, this fix is not permanent, and the issue reoccurs after some time.

System Details:

• Docker version: 27.4.1, build b9d17ea
• Linux distribution: Ubuntu 24.04.1 LTS
• Kernel version: 6.8.0-51-generic x86_64
• Firewall: Firewalld 2.1.1 with nftables v1.0.9 (Old Doc Yak #3)

Update 1:
After testing, a few things I noticed delaying the startup for the service fixes the problem but I am not completely sure if its a proper fix or not

[Unit]
PartOf=firewalld.service

[Service]
ExecStartPre=/bin/sleep 3
Restart=no