Mounted `sif` containers not unmounted after running.

[ast0815]

Version of Singularity

$ singularity --version
singularity version 3.7.3-1.el7

Describe the bug

Singularity does not unmount the sif containers after running. After a while, all loop devices are "used up" and I need to unmount them manually to be able to run again.

To Reproduce

$ mount
...
tmpfs on /run/user/1003 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=796564k,mode=700,uid=1003,gid=1003)
$ singularity run shub://GodloveD/lolcow
INFO:    Use cached image
 ___________________
< Are you a turtle? >
 -------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||
$ mount
...
tmpfs on /run/user/1003 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=796564k,mode=700,uid=1003,gid=1003)
/root/.singularity/cache/shub/a59d8de3121579fe9c95ab8af0297c2e3aefd827 on /run/media/root/disk type squashfs (ro,nosuid,nodev,relatime,seclabel,uhelper=udisks2)
$ singularity run shub://GodloveD/lolcow
INFO:    Use cached image
 ________________________________________
/ You will be advanced socially, without \
\ any special effort on your part.       /
 ----------------------------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||
$ mount
...
tmpfs on /run/user/1003 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=796564k,mode=700,uid=1003,gid=1003)
/root/.singularity/cache/shub/a59d8de3121579fe9c95ab8af0297c2e3aefd827 on /run/media/root/disk type squashfs (ro,nosuid,nodev,relatime,seclabel,uhelper=udisks2)
/root/.singularity/cache/shub/a59d8de3121579fe9c95ab8af0297c2e3aefd827 on /run/media/root/disk1 type squashfs (ro,nosuid,nodev,relatime,seclabel,uhelper=udisks2)

Expected behavior

The mounted loop devices should be unmounted after the container exits.

OS / Linux Distribution

$ cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="http://cern.ch/linux/"
BUG_REPORT_URL="http://cern.ch/linux/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

Installation Method

Installed via yum.

Additional context

Running sandboxes does not seem to be causing any problems. Only the sif container files.

[dtrudg]

Hi @ast0815,

I've dropped the bug label here as singularity does not mount anything under /run/media/xxxx. That location is usually managed by a Linux Desktop Environment or associated process, which auto-mounts CDs, inserted USB sticks etc.

Is this a CERN specific customization of CentOS 7? Which desktop environment (if any) is used?

[ast0815]

I think the machine has Gnome installed (interpreting the output of htop, but I only work on it remotely via SSH.

[dtrudg]

I have done development work on various machines running different versions of GNOME and KDE, and haven't seen this issue.

Singularity does not mount anything under /run/media/xxx so the issue must be due to an external process. In the absence of a way to reproduce, I'll close this as there is nothing we can do here.