snap install-ed docker daemon fails to start with "no available network"

[lestephane]

Feb 28 10:59:57 localhost docker.dockerd[32334]: failed to start daemon: Error initializing network controller:
 list bridge addresses failed: PredefinedLocalScopeDefaultNetworks List: [172.17.0.0/16 172.18.0.0/16 
172.19.0.0/16 172.20.0.0/16 172.21.0.0/16 172.22.0.0/16 172.23.0.0/16 172.24.0.0/16 172.25.0.0/16 
172.26.0.0/16 172.27.0.0/16 172.28.0.0/16 172.29.0.0/16 172.30.0.0/16 172.31.0.0/16 192.168.0.0/20 
192.168.16.0/20 192.168.32.0/20 192.168.48.0/20 192.168.64.0/20 192.168.80.0/20 192.168.96.0/20 
192.168.112.0/20 192.168.128.0/20 192.168.144.0/20 192.168.160.0/20 192.168.176.0/20 192.168.192.0/20 
192.168.208.0/20 192.168.224.0/20 192.168.240.0/20]: no available network

[lestephane]

I found this, which refers to a docker0 interface which I don't have. I would have expected the snap install to create that interface if needed.

[tianon]

Interesting -- this does normally get created automatically. Do you have any more details about your environment that might help us figure out what's going wrong?

[lestephane]

Unfortunately not, now I see a docker0, and the problem has disappeared. I tried many different steps, hard to tell which one solved the problem. I did apt-get install bridge-utils for example, because some blogs explaining docker0 manual creation mentioning it. I thought maybe the snap install logic needed it to create docker0 on my behalf. But I never did create the docker0 interface manually myself. Eventually, docker0 got created, and the docker daemon started without the error.