Docker Won’t Start After Update

I updated docker on CentOS 8 from docker-ce-3:19.03.13-3.el8.x86_64 to docker-ce-3:20.10.1-3.el8.x86_64 and failed to start after update. Oh no, now what? 🙂

"Job for docker.service failed because the control process exited with error code."

Let’s see more details:

sudo journalctl -eu docker

Dec 29 22:43:28 docker.whateverhostname.tld dockerd[9456]: failed to start daemon: Error initializing network controller: Error creating default "bridge" network: Failed to program NAT chain: ZONE_CONFLICT: 'docker0' already bound to a zone

Turned out the fix was to remove trusted.xml, or better move to a backup place in case I’d need it again:

sudo mv /etc/firewalld/zones/trusted.xml /backup/

After this docker and containers within are happy again, yay!

% sudo systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2020-12-29 22:44:42 UTC; 22min ago

Let’s check the firewall now:

% sudo firewall-cmd --state
running

% sudo firewall-cmd --list-all --zone=docker
docker (active)
  target: ACCEPT
  icmp-block-inversion: no
  interfaces: br-22beb4103797 br-256cb1d05e45 br-3567488aa35d br-5c95a1664a2f docker0
  sources:
  services:
  ports:
  protocols:
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules: