I'm trying to run imageio tests on el8 mock, and the tests fail early when trying to create storage

for testing:

[userstorage] INFO    Creating filesystem /var/tmp/imageio-storage/file-512-ext4-mount
Suggestion: Use Linux kernel >= 3.18 for improved stability of the metadata and journal checksum features.
[userstorage] INFO    Creating file /var/tmp/imageio-storage/file-512-ext4-mount/file
[userstorage] INFO    Creating backing file /var/tmp/imageio-storage/file-512-xfs-backing
[userstorage] INFO    Creating loop device /var/tmp/imageio-storage/file-512-xfs-loop
[userstorage] INFO    Creating filesystem /var/tmp/imageio-storage/file-512-xfs-mount
mount: /var/tmp/imageio-storage/file-512-xfs-mount: wrong fs type, bad option, bad superblock on /dev/loop4, missing codepage or helper program, or other error.
Traceback (most recent call last):
  File "/usr/local/bin/userstorage", line 10, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.6/site-packages/userstorage/__main__.py", line 42, in main
    create(cfg)
  File "/usr/local/lib/python3.6/site-packages/userstorage/__main__.py", line 52, in create
    b.create()
  File "/usr/local/lib/python3.6/site-packages/userstorage/file.py", line 47, in create
    self._mount.create()
  File "/usr/local/lib/python3.6/site-packages/userstorage/mount.py", line 53, in create
    self._mount_loop()
  File "/usr/local/lib/python3.6/site-packages/userstorage/mount.py", line 94, in _mount_loop
    ["sudo", "mount", "-t", self.fstype, self._loop.path, self.path])
  File "/usr/lib64/python3.6/subprocess.py", line 311, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', 'mount', '-t', 'xfs', '/var/tmp/imageio-storage/file-512-xfs-loop', '/var/tmp/imageio-storage/file-512-xfs-mount']' returned non-zero exit status 32.

https://jenkins.ovirt.org/job/ovirt-imageio_standard-check-patch/1593//artifact/check-patch.el8.ppc64le/mock_logs/script/stdout_stderr.log

Same code runs fine in Travis:

https://travis-ci.org/nirs/ovirt-imageio/jobs/595794863

And also locally on Fedora 29:

$ ../jenkins/mock_configs/mock_runner.sh -C ../jenkins/mock_configs -p el8

...

## Wed Oct  9 23:37:22 IDT 2019 Finished env: el8:epel-8-x86_64
##      took 85 seconds
##      rc = 0

My guess is that we run el8 jobs on el7 hosts with old kernels

(Suggestion: Use Linux kernel >= 3.18 for improved stability of the metadata and journal checksum features.)

This issue will affects vdsm, using similar code to create storage for testing.

For vdsm the issue is more tricky, since it requires same host/distro:

 49         - tests-py37:
 50             runtime-requirements:
 51               host-distro: same

So I think we need:

- make slaves with newer kernel (fc29? fc30?) with the el8 mock env

- add el8 slaves for running el8 mock with "host-distro: same"

If we don't have a solution we need to disable el8 tests, or continue testing without

storage, which will skip about 200 tests.

Nir