no apparent support for loop devices!FAILED to loop mount image

[liuxiaopiao]

When using shifter, met the below error when starting container: [test@slurm-ctl18 ~]$ shifter --image=alpine ERROR: no apparent support for loop devices!FAILED to loop mount image: /images/f33084b4b6032f9c77744a165174368fa4aed696ac301bfe504fa5533121690f.squashfs FAILED to mount image on loop device. FAILED to setup image. Image can pull successfully and also did [test@slurm-ctl18 ~]$ sudo modprobe loop [test@slurm-ctl18 ~]$ lsmod | grep loop loop 32768 0 [test@slurm-ctl18 ~]$ echo loop > /etc/modules-load.d/loop.conf I have followed the step mentioned in https://github.com/NERSC/shifter/blob/master/doc/install/centos7.rst#id1 and built with Slurm support.
Could you please help me give me some suggestions on this? Thanks a lot

[dmjacobsen]

it looks like shifter is looking for /dev/loop0

do you have /dev/loop0?

[liuxiaopiao]

Thanks @dmjacobsen a lot for helping checking this. I didn't have /dev/loop0 on this vm. [test@slurm-ctl18 ~]$ ls -ltr /dev/loop* crw-rw----. 1 root disk 10, 237 Dec 18 22:00 /dev/loop-control

Do I need to create one /dev/loop0 manually before running the shifter container?

[liuxiaopiao]

Manually created one /dev/loop0 and now it works.

But I have installed 17.11 version rpms which are downloaded from http://portal.nersc.gov/project/bigdata/shifter/ and it works fine without manually creating /dev/loop0.

So want to know

1. why we need to create this manually.
2. Is it special for shifter package with slurm support.
3. Is it special for 18.03 version?

@dmjacobsen , could you please give me a hand on this when you have bandwidth? Thanks a lot.

[scanon]

This is dependent on the host system. The loop back is used through Shifter. So not unique to the Slurm integration.

The 18.03 has several new features and is a little easier to deploy. I'll take an action to create some new RPMs and advertise those.

[scanon]

Closing this.