So this one is pretty simple. However , I found a lot of false information along the way, so I figured that I might jot the proper (and most simple) process here.
Symptoms : the RHEL (or variant) VM that will takes a very long time to boot. On the VM console, you can see the following output as the VM boot process is stalled and waiting for a timeout. Note that the message below has nothing to do with cloud init, but its the output that I have got most often seen on the console while waiting for a VM to boot.
[106. 325574} random: crng init done
Note that I have encounter this issue in both OpenStack (when boot-up from external provider networks) and in KVM.
Upon initial boot of the VM, run the command below.
touch /etc/cloud/cloud-init. disabled