gitblit is hosted on antinomy.wikimedia.org which only have the default checks: puppet freshness, NTP and SSH.
https://icinga.wikimedia.org/cgi-bin/icinga/status.cgi?search_string=antimony
It would need a check that monitor whether gitblit is running.
templates/icinga/nrpe_local.cfg.erb has a bunch of examples if you look for 'java'. An example for Jenkins:
command[check_jenkins]=/usr/lib/nagios/plugins/check_procs -w 1:1 -c 1:1 --ereg-argument-array '^/usr/bin/java .*-jar /usr/share/jenkins/jenkins.war'
Which make sure there is one and only one java process with jenkins.war.
Version: wmf-deployment
Severity: enhancement