Error running DeleteDevice dm_task_run failed
重啟docker即可
Error starting daemon: error initializing graphdriver: \"/var/lib/docker\" contains several valid graphdrivers: devicemapper, overlay; Please cleanup or explicitly choose storage driver (-s <DRIVER>)
到/var/lib/docker根據情況，將下面的overlay或者devicemapper文件夾刪掉即可。這種情況發生在使用采用dc/os安裝后，原有的devicemapper模式修改成了overlay，但是docker同時只能支持一種存儲模式。