Trying to get my facts straight here.
Is Sensu (pretty new kid on the block) meant to be a replacement for both the following?:
- Nagios (monitoring & alerting)
- collectD (feeding info to Nagios in this setup)
Let's summarize what each of these programs do-
Nagios and sensu are comparable software, but collectd is not. You could imagine using collectd to feed nagios data via ncsa or feed sensu data via amqp, although doing either of these would require writing new plugins for collectd.
I suspect it's possible to use Sensu as a replacement for Nagios (it supports checks and actions)..
As far as replacing collectD, perhaps. It's difficult to tell without asking someone who actually works on it.
My first thought was "Hmm, only release 0.9, I wonder if it's really ready for production use".