On Ubuntu 16.04 Docker fails to start on system startup if Docker was configured to use devicemapper as storage driver with direct-lvm as storage-pool. The following errors occur
#$ sudo systemctl status docker ● docker.service - Docker Application Container Engine Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Di 2016-07-12 16:22:33 CEST; 1min 30s ago Docs: Process: 1880 ExecStart=/usr/bin/docker daemon -H fd:// $DOCKER_OPTS (code=exited, status=1/FAILURE) Main PID: 1880 (code=exited, status=1/FAILURE) Jul 12 16:22:33 docker-lvm systemd[1]: Starting Docker Application Container Engine... Jul 12 16:22:33 docker-lvm docker[1880]: time="2016-07-12T16:22:33.304838820+02:00" level=fatal msg="Error starting daemon: error initializing graphdriver: devicemapper: Non existing device ubuntu--vg-thinpool" Jul 12 16:22:33 docker-lvm systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILURE Jul 12 16:22:33 docker-lvm systemd[1]: Failed to start Docker Application Container Engine. Jul 12 16:22:33 docker-lvm systemd[1]: docker.service: Unit entered failed state. Jul 12 16:22:33 docker-lvm systemd[1]: docker.service: Failed with result 'exit-code'. Jul 12 16:22:33 docker-lvm systemd[1]: docker.service: Start request repeated too quickly. Jul 12 16:22:33 docker-lvm systemd[1]: Failed to start Docker Application Container Engine.
1 Answer
The status messages indicated that my thinpool was not available. lvdisplay said the same:
#$ sudo lvdisplay ubuntu-vg/thinpool --- Logical volume --- LV Name thinpool VG Name ubuntu-vg LV UUID Or2cLx-ENFq-sZqh-kxUw-0FEQ-rEzi-vXCi3C LV Write Access read/write LV Creation host, time docker-lvm, 2016-07-12 15:57:06 +0200 LV Pool metadata thinpool_tmeta LV Pool data thinpool_tdata LV Status NOT available LV Size 14,07 GiB Current LE 3601 Segments 1 Allocation inherit Read ahead sectors auto
Note: LV Status NOT available
Trying to activate it said:
#$ sudo lvchange -ay ubuntu-vg/thinpool /usr/sbin/thin_check: execvp failed: No such file or directory Check of pool ubuntu-vg/thinpool failed (status:2). Manual repair required!
The tools for thinpools are configured in /etc/lvm/lvm.conf and there i found the following paragraph:
# Configuration option global/thin_check_executable. # The full path to the thin_check command. # LVM uses this command to check that a thin metadata device is in a # usable state. When a thin pool is activated and after it is # deactivated, this command is run. Activation will only proceed if # the command has an exit status of 0. Set to "" to skip this check. # (Not recommended.) Also see thin_check_options. # (See package device-mapper-persistent-data or thin-provisioning-tools) # This configuration option has an automatic default value. # thin_check_executable = "/usr/sbin/thin_check"I looked up the packages mentioned there and i found that the package thin-provisioning-tools is available but not installed.
#$ sudo apt-cache policy thin-provisioning-tools thin-provisioning-tools: Installed: (none) Candidate: 0.5.6-1ubuntu1 Version table: 0.5.6-1ubuntu1 500 500 xenial/universe amd64 Packages
After installation the package the utils for thinpools were available. Manual Activation of the docker-thinpool succeeded and also on system startup the volume was activated and docker starts successfully.
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