I'm working on a small EC2 project that involves a handful of servers in two different regions (US East and EU West). My first task is to implement a Nagios monitoring solution. Monitoring within a region is simple - I just use the private domain names/IPs, but I'm a little unsure of the best way to handle monitoring the second region without setting up a second Nagios install. The environment is fairly static, so I'm not going to be scripting the configuration with the EC2 tools just yet.

As I see it, I have two options.

1. Two Nagios installations (which is over-kill for the small number of servers I'm dealing with).
   Pros: I don't have to alter the group permissions nor do I have to pay for the traffic, redundancy in the monitoring solution - I could monitor the Nagios servers.
   Cons: two installations to deal with and I'd need to run another server instance.
2. Have the single installation monitor both regions.
   Pros: one installation to deal with.
   Cons: slightly reduced security - security group will have to have NRPE (5666) opened for one source IP and also paying for a small amount of bandwidth at the Internet rate for data transfer between the regions.

I guess my question is - how have others handled this problem and what are your recommendations?

Thanks!