Some thoughs on mod_gearman benefits.
- It calls back Gearmand, so it can be fitted in a vlan behind a firewall and you do not have to open any ports towards the vlan;
- You can have more than one worker to monitor a host or service. They share the load, so you have a round robin balancing and if one faints, the others take all the checks and execute them. So, you have an easy way to redundancy for the workers.
In this chart I “collapsed” the gearmand daemon under the “Monitor” box.