If necessary, you can utilize various hardware random number generators to create entropy, or you can use a less secure method of running rng-tools to create pseudorandom entropy that is piped to /dev/random. For example, you can use rngd -r /dev/urandom to run the RNG service on /dev/urandom. The process immediately daemonizes and begins running in the background. Sufficient levels of entropy should then be generated to resolve the entropy starvation, causing any processes that are blocked due to low entropy in /dev/random to immediately start running again.
For instructions on configuring the carry over of seed data in the entropy pool across shut-downs and start-ups, refer to the urandom man pages on your server.