I install docker - 1.12.6 - 28 on CentOS 7 and use it.
In that Docker, multiple containers are operating normally, and it operated for about a month without any problem.
The other day, after stopping the docer engine service, I attempted to start the service by executing “systemctl start docker” command but the following message was displayed and failed to start.
June 19 15:07:00 HOSTNAME dockerd-current [16984]: time = “2017-06-19T15: 07: 00.335816789 + 09: 00” level = error msg = "[graphdriver] prior storage driver " devicemapper \ Failed: devmapper: Base Device UUID and Filesystem verification failed: devicemapper: Can not set cookie dm_task_set_cookie failed "
June 19 15:07:00 HOSTNAME dockerd-current [16984]: time = “2017-06-19T15: 07: 00.335880077 + 09: 00” level = fatal msg = "Error starting daemon: error initializing graphdriver: devmapper: Base Device UUID and Filesystem verification failed: devicemapper: Can not set cookie dm_task_set_cookie failed "
After that, trial and error, the following corrections were made, the service started.
-execute command “Dmsetup udevcomplete_all 10”
-Added “- s devicemapper” to OPTIONS of file “/etc/sysconfig/docker”
I was able to start up, but I can not understand why it came up and why.
Please tell me why.