[LTP] [PATCH] nfs: Adapt the lib to allow to test in 2-host mode

[Petr Vorel]

> Hi!
> > > And with that we would need some kind of "master file" that would
> > > explain which script should be executed on which host etc. But I guess
> > > that it would be tricky to desing this properly.

> > I'm not sure if separated file is worth of adding. There is tst_rhost_run()
> > function which should be used for checking, which works well on both netns and 2
> > host based setup (that's why v2).

> This is just me thinking if we can actually desing something more proper
> in the future now that runltp is gone. I think that the whole
> tst_rhost_run() infrastructure is a bit of a hack and that the
> multimachine test can be desingned differently. I would say that more
> proper solution would be to have the test split into one script per
> worker and having some master script/description to drive the testing.
> The testrunner would read the information about which script to run on
> which worker and would also have to handle synchronization.

FYI tst_rhost_run() is used for testing itself as well, more than for setup and
cleanup:

$ git grep -l tst_rhost_run |wc -l
35

Therefore we can rethink network test setup, but tst_rhost_run() will be needed
anyway.

> In the case of the NFS tests the master script would say to run a script
> that sets up NFS server and signal the testrunner once it's done and
> wait. The script that would be doing the actuall test would be executed
> once the the NFS server script to signaled it's completion and then
> start the actual test. Once it's finished testing it would exit, which
> would tell the testrunner to wake up the NFS server script in order to
> cleanup. If we decided to write multimachine tests this way we would
> need to add a way how to pass parameters such as IP addresses from kirk
> to tests and also add a way how to propagate events between tests via
> kirk so that we can have some kind of locking.

Also, you call it a hack, but it works standalone, without any runner. I would
be careful to add kirk as a hard dependency to run a single test without a
strong reason (sure, using kirk to handle metadata to run tests in paralel or
replace runtest files will be a great improvement, but I would like to still
keep executing a test itself by just calling it with proper PATH setup).

FYI "multimachine tests": I know only about 1 test which needs more than a
single machine: IPsec (implemented in openQA instead of LTP [1]).

Kind regards,
Petr

[1] https://github.com/linux-test-project/ltp/issues/920