Make sure rngd, a hardware RNG entropy gatherer daemon, is installed on
all DIB-built Red Hat family distro images. rngd comes installed by
default in a typical base installation as it's proven to help speed
things up.
Nova attaches the virtio-rng-pci device to VMs. virtio-rng-pci is a
device that provides feed random data. However, it is of little to no
use if the virtual machine is not configured to make use of given
device. That is where rngd can help by facilitating entropy to the pool
from virtio-rng-pci.
$ openstack image set --property hw_rng_model=virtio [...]
$ openstack flavor set --property hw_rng:allowed=True [...]
DIB-built minimal images do not come with rngd installed. This patch
makes sure the daemon is installed. Its systemd service comes already
enabled.
Change-Id: I34a989dbfc57d4c98113ac25c81dfb500945ff0a