capi1O
commented
7 years ago Hi, I have a similar problem (logical volumes are not mounted when their corresponding docker volumes are used) but it happens even after a clean reboot.
As echa I then need to manually reset the counts in /var/lib/docker-lvm-plugin/lvmCountConfig.json for each docker volume and to restart docker-lvm-plugin and docker services (sudo systemctl restart docker-lvm-plugin and sudo systemctl restart docker).
Otherwise I have to manually mount the LV to the path specified in the docker volume. Ex for a docker volume named my-lv :
docker volume inspect my-lv :
[
{
"Name": "my-lv",
"Driver": "lvm",
"Mountpoint": "/var/lib/docker-lvm-plugin/my-lv",
"Labels": {},
"Scope": "local"
}
]sudo lvdisplay :
--- Logical volume ---
LV Path /dev/docker-vg/my-lv
LV Name my-lv
...After reboot the docker volume is not "linked" to the LV anymore (because LV is not mounted at the path specified by the docker volume) but it becomes a host directory mounted as a docker volume : data is stored on host in the dir at path /var/lib/docker-lvm-plugin/my-lv.
I need to manually mount the LV at this path to "link" back the LV to the docker volume :
sudo mount /dev/docker-vg/my-lv /var/lib/docker-lvm-plugin/my-lv
- docker-lvm-plugin version : git commit d918081f6b3e2944e2c6819b93f59a21e03fd85a
- go version : go1.6.2 linux/amd64
- godep version : godep v74 (linux/amd64/go1.6.2)
- docker version : 1.12.1-0ubuntu13~16.04.1
- docker host version : ubuntu 16.04 LTS
From the info I found the purpose of the count property of lvmDriver (that is saved to disk for each docker volume/LV in this lvmCountConfig.json file) is to keep count of how many docker containers use this volume, so a docker volume cannot be not removed when at least 1 container is using it (as explained here https://github.com/docker/docker/issues/17585).
Docker requires the plugin to provide a volume, given a user specified volume name. This is called once per container start. If the same volume_name is requested more than once, the plugin may need to keep track of each new mount request and provision at the first mount request and deprovision at the last corresponding unmount request.
source : https://docs.docker.com/engine/extend/plugins_volume/
Volumes are removed explicitly (i.e., docker volume rm) or implicitly via container remove (i.e., docker rm -v). Docker will only send a remove request to a volume driver when the internal reference count drops to zero. Since Docker’s reference counting is not multi-host aware, the volume driver must be.
source : http://www.blockbridge.com/multi-host-volumes-semantics-with-docker-1-9/
But I don't see how it relates to this mounting problem. Plus I did not really get this :
these are files for persisting the state of the memory stores on disk
source : https://github.com/shishir-a412ed/docker-lvm-plugin/issues/15
shishir-a412ed
maartenl945
echa
Hey guys, I just experienced a server crash and after reboot my existing lvm volumes never got auto-mounted again. Looking at the code this is to be expected.
Reason is that you trust information in
/var/lib/docker-lvm-plugin/lvmCountConfig.jsoneven after an unclean shutdown/crash. Counts were still set to 1 in my case since this was the last alive state (containers running, docker running, volumes mounted by kernel and exposed to containers).After manually resetting all counters to 0 and restarting docker + docker-lvm-plugin services the auto-mount worked as expected.
System was a CentOS 7.2 + EPEL:
docker version
Client: Version: 1.10.3 API version: 1.22 Package version: docker-common-1.10.3-46.el7.centos.14.x86_64 Go version: go1.6.3 Git commit: cb079f6-unsupported Built: Fri Sep 16 13:24:25 2016 OS/Arch: linux/amd64
Server: Version: 1.10.3 API version: 1.22 Package version: docker-common-1.10.3-46.el7.centos.14.x86_64 Go version: go1.6.3 Git commit: cb079f6-unsupported Built: Fri Sep 16 13:24:25 2016 OS/Arch: linux/amd64
yum info docker-lvm-plugin
Installed Packages Name : docker-lvm-plugin Arch : x86_64 Version : 1.10.3 Release : 46.el7.centos.14 Size : 8.6 M Repo : installed From repo : extras Summary : Docker volume driver for lvm volumes URL : https://github.com/docker/docker License : LGPLv3 Description : Docker Volume Driver for lvm volumes.