[ovirt-devel] ovirt-imageio leaves .guestfs-0 folder under /var/tmp during check-patch

[Barak Korren]

On 25 May 2017 at 15:42, Nir Soffer <nsoffer at redhat.com> wrote:
>
> In this case, I don't see how vdsm tests can pollute the host /var/tmp.
>
> Vdsm run 2 tests running virt-alignment-scan, one with --help, and one
> with non existing images, so the temporary directory cannot be created
> by these tests.

As you see in $subject, we are looking for something that is invoking
libgustfs, could vdsm or imageio be doing that?

> We need a location which exists on developer laptop, developer hosts,
> and CI environments, and /var/tmp proved to be a good choice so far.
> We expect that ovirt CI will not break this assumption in the future.

One thing you can do is use something like "/var/tmp/vdst_test" and
also include that string in an "automation/*.mounts" file. This will
cause 'mock_runner.sh' to mkdir and bind-mount it into the environment
so you are using the hosts real '/var/tmp/vdsm_test' which will
probably remain a real file-system for the time being.

But if you do this, please clean up when you're done...

> However, writing test data to storage is a waste of time, and having
> a memory based file system supporting direct I/O would speed up lot
> of tests.
>
> So we can do this:
>
> truncate -s 5g /tmp/backing
> mkfs.ext4 /tmp/backing
> mount -o loop /tmp/backing /tmp/mnt
>
> And now we have direct I/O support and great performance:
>
> This requires root to mounting and unmounting the backing file, so
> it is not a good solution for developers, when you need to run certain
> tests all the time, but it can be a good solution for the CI.

Have you tried doing this from inside mock? You are root there so it might work.

But note that /tmp is not in RAM in EL7. Better use /dev/shm for compatibility.

> Barak, do you think ovirt CI can provide this functionality?

I guess we could come up with some special syntax in the '*.mounts'
file to support something like this, but I'd rather not add any big
features to mock_runner before we rewrite it to use containers.

-- 
Barak Korren
RHV DevOps team , RHCE, RHCi
Red Hat EMEA
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