Cannot connect to the Docker daemon at unix:///var/run/docker.sock

General
1

i am struggling with docker demon start after pointing docker to use a device mapper. my configuration given below

Can someone please tell me what am i doing wrong here

sudo systemctl status docker

● docker.service
Loaded: loaded (/etc/systemd/system/docker.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Wed 2017-08-30 12:46:01 PDT; 5s ago
Process: 29286 ExecStart=/usr/bin/docker --iptables=false --storage-driver=devicemapper --storage-opt=dm.thinpooldev=/dev/mapper/docker-thinpool --storage-opt=dm.use_deferred_removal=true --storage-opt=dm.use_deferred_deletion=true --storage-opt=dm.basesize=6G (code=exited, status=125)
Main PID: 29286 (code=exited, status=125)

Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: start Start one or more stopped containers
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: stats Display a live stream of container(s) resource usage statistics
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: stop Stop one or more running containers
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: top Display the running processes of a container
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: unpause Unpause all processes within one or more containers
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: update Update configuration of one or more containers
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: version Show the Docker version information
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: wait Block until one or more containers stop, then print their exit codes
Aug 30 12:46:01 docker-vm.rackwareinc.lab docker[29286]: Run ‘docker COMMAND --help’ for more information on a command.

[root@docker-vm ~]# docker info
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

[root@docker-vm ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
fd0 2:0 1 4K 0 disk
sda 8:0 0 50G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 49.5G 0 part
├─rhel-root 253:0 0 45.6G 0 lvm /
└─rhel-swap 253:1 0 3.9G 0 lvm [SWAP]
sdb 8:16 0 10G 0 disk
├─sdb1 8:17 0 5G 0 part
└─sdb2 8:18 0 5G 0 part
sdc 8:32 0 10G 0 disk
├─vg01DockerPool-thinpool_tmeta 253:3 0 100M 0 lvm
│ └─vg01DockerPool-thinpool 253:5 0 9.5G 0 lvm
└─vg01DockerPool-thinpool_tdata 253:4 0 9.5G 0 lvm
└─vg01DockerPool-thinpool 253:5 0 9.5G 0 lvm
sdd 8:48 0 10G 0 disk
├─docker-fkdocker_thinpool_tmeta 253:2 0 100M 0 lvm
│ └─docker-fkdocker_thinpool 253:7 0 9.5G 0 lvm
└─docker-fkdocker_thinpool_tdata 253:6 0 9.5G 0 lvm
└─docker-fkdocker_thinpool 253:7 0 9.5G 0 lvm
sr0 11:0 1 1024M 0 rom

If incase if i revert my changes it does without any issues …i just want to use /dev/sdd as a mapper device for thin pool to provision containers on volumes

2

Can you check the contents of /var/lib/docker/devicemapper/metadata/deviceset-metadata? I think it is pointing to the UUID of the old device - sda (?)

You can also look at the docker journal logs to get the correct UUID to update the file with.