What is the meaning of holdoff time over in systemd services?

I have installed Puppet Enterprise on CentOS 7. I can see that several Puppet services fail to start saying holdoff time over. What does this mean?

Sep 03 20:50:16 l-pm1 systemd[1]: pe-puppetdb.service holdoff time over, scheduling restart.
Sep 03 20:50:16 l-pm1 systemd[1]: Starting pe-puppetdb Service...

Solution 1:

After a service stops (or fails to start), systemd waits for a short period of time before attempting to restart it.

The amount of wait time is configurable by setting RestartSec= in the unit.

RestartSec=

Configures the time to sleep before restarting a service (as configured with Restart=). Takes a unit-less value in seconds, or a time span value such as "5min 20s". Defaults to 100ms.