#OSCON – One tiny daemon to harvest your server statistics (and more)

• Presenter: Brandon Philips, Rackspace
• External monitoring: ping, nmap, curl. Lest we forget nagios, ganglia, cacti, zenoss, noitd
• Internal monitoring: scripts gathering stats, pushing to a monitoring server
• Beware cron’d monitoring agents – not going to help you much during panic conditions.  Whereas a daemon, you might be able to communicate with it.
• Overview: agent runs in the cloud, with TLS connection to a stud in each datacentre
• Rackspace’s monitoring agent is Virgo
  • Designed for low memory usage
  • Simple secure ‘proxyable’ protocol
  • High level scripting language
  • Designed to be statically linked
  • Avoided C++, used Lua instead (JavaScript’s long lost Brazilian cousin)
  • SSL + JSON newline delimitted + JSONRPC-esque
  • libuv
  • luvit
  • luajit
  • Lua code lives in a single zip file. Makes it easy to do upgrades and reduces presence on a client’s host.
  • Sigar for gathering system metrics.
• Virgo agent uses ~5mb memory, less than python (~9mb), ruby (~15mb) or c++ (~20mb)
• Slides posted here