Entropy is nothing but the measure of randomness in a sequence of bits. The PRNG ( pseudorandom number generator ) is a special device (e.g. /dev/random on Linux) to create randomness from server hardware activities. It uses interrupts generated from the keyboard, hard disk, mouse, network and other sources. The random number generator gathers environmental noise from device drivers and other sources into an entropy pool. In this post, I will cover haveged and rng-utils/rng-tools to generate random numbers and feed linux random device for your virtual or dedicated Linux server.