I am running Docker 1.12.5 on CentOS 7.2 . I have converted Docker to use Devicemapper with direct-lvm, since Devicemapper with default loop devices is not good for production:
[root@docker01 ~]# docker info | less Containers: 35 Running: 22 Paused: 0 Stopped: 13 Images: 48 Server Version: 1.12.5 Storage Driver: devicemapper Pool Name: docker-thinpool Pool Blocksize: 524.3 kB Base Device Size: 10.74 GB Backing Filesystem: xfs Data file: Metadata file: Data Space Used: 16.51 GB Data Space Total: 255 GB Data Space Available: 238.5 GB Metadata Space Used: 6.316 MB Metadata Space Total: 2.68 GB Metadata Space Available: 2.674 GB Thin Pool Minimum Free Space: 25.5 GB Udev Sync Supported: true Deferred Removal Enabled: true Deferred Deletion Enabled: true Deferred Deleted Device Count: 0 Library Version: 1.02.135-RHEL7 (2016-09-28) Data Space Available: 238.5 GB ...
On one of my Docker hosts, the / volume filled up. When I looked deeper, I noticed that the files for some containers actually reside on / , while other are a
shm device and seem to use the Devicemapper direct-lvm device.
For example, this container uses shm:
[root@docker01 ~]# df -h /var/lib/docker/containers/fdad640aabb19b7a6a8712edecb5a4123d8c29736f939e213cf8d09ca7151b7d/shm/ Filesystem Size Used Avail Use% Mounted on shm 64M 0 64M 0% /var/lib/docker/containers/fdad640aabb19b7a6a8712edecb5a4123d8c29736f939e213cf8d09ca7151b7d/shm [root@docker01 ~]#
However, this container uses the root filesystem:
[root@docker01 ~]# df -h /var/lib/docker/containers/ffce9d013b613534984f191ccddca83ed6ce949812a1584556b519cd9626f52c/shm/ Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_01-lv_root 9.8G 9.8G 20K 100% / [root@docker01 ~]#
Shouldn’t all of these Containers use an actual