Description of problem: In nova/conf/libvirt.py there is: cfg.StrOpt('rng_dev_path', help='A path to a device that will be used as source of ' 'entropy on the host. Permitted options are: ' '/dev/random or /dev/hwrng'), This note about devices is outdated. Since libvirt 1.3.4, any path is permitted: https://libvirt.org/formatdomain.html#elementsRng And in particular /dev/urandom *is* a valid choice, and indeed a good default choice, since /dev/random is quite limited and easily blocks.
See also https://bugzilla.redhat.com/show_bug.cgi?id=1074464
Patch posted: https://review.openstack.org/577385 conf: libvirt: Update the outdated `rng_dev_path` docs
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2019:0045