hb_report is an error reporting tool that comes with heartbeat >= version 2.1.3. It collects all information needed to describe your cluster configuration and what happened over a given time period and packs them into one tar.gz file. This file can be posted to the mailinglist and will contain the information we need to help you out. It is still helpful if you explain your hardware and network setup, though 
hb_report relies on ssh to collect the information. Therefore it might ask you for passwords while it is running. Ssh with publickey authentication can help here.
Say you want to create a report for the time between 10 am and 10.30 am, you can easily create one like this:
hb_report -u root -f 10:00 -t 10:30 /tmp/myreport
This will create /tmp/myreport.tar.gz, which you can attach as an attachment to your problem description in bugzilla.