The following commands will help increase entropy in a headless server . For example any cloud server.

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
sudo rpm -Uvh epel-release-latest-7*.rpm
yum install haveged
yum install rng-tools
systemctl start haveged
systemctl enable haveged
cat /dev/random | rngtest -c 1000