To facilitate GPU plugin scalability testing on a real cluster.
Pre-existing (fake) sysfs & devfs content needs to be removed first:
* Fake devfs directory is mounted from host so OCI runtime can "mount"
device files also to workloads requesting fake devices. This means
that those files can persist over fake GPU plugin life-time, and
earlier files need to be removed, as they may not match
* DaemonSet restarts failing init containers, so errors about content
created on previous generator run would prevent getting logs of the
real error on first generator run
* Before removal, check that removed directory content is as expected,
to avoid accidentally removing host sysfs/devfs content (in case
container was erronously granted access to the real thing)
Container runtime requires fake device files to real be devices:
* Use NULL devices to represent fake GPU devices:
https://www.kernel.org/doc/Documentation/admin-guide/devices.txt
* Give more detailed logging for MkNod() failures as device
node creation is most likely operation to fail when container
does not have the necessary access rights
Created content is based on JSON config file (instead of e.g.
commandline options) so that (configMap providing) it can be updated
independently of the pod where generator is run.
Signed-off-by: Eero Tamminen <eero.t.tamminen@intel.com>
