Certificate Hub data encryption operations require a robust entropy source to improve randomness. To check if your host system has enough entropy, run the following command.

head -c 8192 /dev/random | hexdump

If the command completes almost immediately, the server has enough entropy. However, if it takes several minutes, the server has not enough entropy, and you must install the rngd daemon.

sudo yum -y install rng-tools
sudo systemctl start rngd
sudo systemctl enable rngd

Run the above commands in the host machine because the Docker containers use the entropy provided by the host machine.