Some environments with low entropy might experience intermittent performance issues with SSL-based communication, such as certificate generation. This scenario is more typical on virtual machines but can also occur in physical instances. For best results, monitor the value of kernel.random.entropy_avail in the configuration file /etc/sysctl.conf.

To increase system entropy on a Windows system, move the mouse pointer in circles or type characters randomly into an empty text document.

  • On a UNIX or Linux system, ensure that rng-tools is installed and run the following command.
    sudo rngd -r /dev/urandom -o /dev/random
  • To check the level of a system entropy on a UNIX or Linux system, run the following command.
    cat /proc/sys/kernel/random/entropy_avail

    Values smaller than 3200 are considered too low to generate a certificate and might cause the system to hang indefinitely.