What does this docker log entry mean?

Solution 1:

I had docker package installed through apt and snap at the same time. So the issue is fixed by removing docker through the snap packaging system.

# apt list --installed | grep docker   
docker/bionic,now 1.5-1build1 amd64 [installed]
docker-ce/bionic,now 5:19.03.5~3-0~ubuntu-bionic amd64 [installed]
docker-ce-cli/bionic,now 5:19.03.5~3-0~ubuntu-bionic amd64 [installed,automatic]

# snap list | grep docker
docker                18.09.9                     418   stable    canonical✓  -

# snap remove docker
docker removed

Solution 2:

Someone at Cannonical screw things up few hours ago - it's tracked on launchpad - https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1852720

My system was installed yesterday with docker only and same as rest of folks here - syslog killed entire free space on disk, purging docker from snap helped.