[CRIU] Adding pre-migration checks into criu

[Adrian Reber]

Sometimes migration of a process is not possible and it is not really
CRIU faults that it doesn't work. Simplest reasons are the binary is not
available or different size, libraries are missing, files are missing or
cgroup structure are not available.

I was thinking of adding something to CRIU which checks all these
obvious reasons for restoration failures.

My first idea was to add an option to make a light-dump and a light-restore.
It would be checkpoint without ending the process and without dumping
the memory. This light-checkpoint could then be transferred to the
destination system to make sure all the simple and obvious errors can be
excluded and that the chances that the process will be restored are much
higher.

That the binary and the libraries do exist on the destination system,
that they have the same size and MD5/SHA1/SHAsomething, that all
required files are available and that enough free memory is available
can easily be done in external tools, but as CRIU knows how to collect
these informations already it seems to make sense to include this into
CRIU.

Does this sound useful or maybe even completely wrong?

		Adrian