RNGD service consuming high CPU usage after pointing /dev/random to behave as urandom

[Sachin Aryal]

I have executed these commands while installing my application on Ubuntu system.

The following commands are specific for /dev/random to behave as urandom

sudo rm /dev/random
sudo mknod /dev/random c 1 9 # make /dev/random behave as urandom. 1 and 9 are device numbers of urandom
adding above changes to rc.local to make system changes persistent after reboot

sed -i -e "/^exit 0/ i\sudo rm /dev/random" -e "/^exit 0/ i\sudo mknod /dev/random c 1 9" /etc/rc.local
After executing these command I restarted the rng-tools

sudo systemctl restart rng-tools
And suddenly after restarting rng-tools , top command shows 100% CPU usage by rngd service.

My System Information:

NAME="Ubuntu"
VERSION="16.04.1 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.1 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
UBUNTU_CODENAME=xenial

and when I restore /dev/random to its normal behavior and restart the rng-tools and the CPU usage changes to normal.