There's a race condition when trying to perform file injection without
libguestfs, which causes a fallback to nbd device. Although the kpartx
command succeeds, it does so after the code has tested for success, so
Nova thinks it failed.
Retry a few times to avoid this.
Co-Authored-By: Paul Carlton <paul.carlton2@hp.com>
Change-Id: Ie5c186562475cd56c55520ad7123f47a0130b2a4
Closes-Bug: #1428639
Closes-Bug: #1484586