God 0.6.0 released (and mailing list)

!!!NEW MAILING LIST!!! We now have a mailing list at

This release is primarily focused on increased stability, robustness,
and code cleanliness.

The last release (0.5.0) switched from TCP sockets to Unix Domain
Sockets for the CLI tools. There were some issues regarding file
descriptors that would cause god to hang when restarting (the unix
socket was being held open by spawned processes). These problems are all
fixed in 0.6.0. You may need to kill any processes that were started
under god 0.5.0 when you upgrade to 0.6.0 (you will only need to do this
once during the upgrade process).

More attention is now paid to Syslogging behavior.

God will delete its own PID file when terminated via a user request.

A new command line option now allows you to check whether your
installation properly handles events (sometimes the C extension will
compile ok, but still not support events. Gentoo, I’m looking at you).
Run god check to see an attempt to use the event system. It will tell
you if your installation does not support events.

A watch can now be removed entirely at runtime using god remove <watch name>.

A new condition DiskUsage allows you to check the available disk space
on a given volume.

Updated documentation is now available on the website:



God is an easy to configure, easy to extend monitoring framework written
in Ruby.

Keeping your server processes and tasks running should be a simple part
of your deployment process. God aims to be the simplest, most powerful
monitoring application available.


God is still beta so I do not yet recommend you use it for mission
critical tasks. We are using it at Powerset, Inc. to monitor our public
facing applications, but then, we’re daring fellows.


sudo gem install god


  • Config file is written in Ruby
  • Easily write your own custom conditions in Ruby
  • Supports both poll and event based conditions
  • Different poll conditions can have different intervals
  • Easily control non-daemonized processes


The easiest way to understand how god will make your life better is by
looking at a sample config file. The following configuration file is
what I use at gravatar.com to keep the mongrels running:

run with: god -c /path/to/gravatar.god

This is the actual config file used to keep the mongrels of

gravatar.com running.

RAILS_ROOT = “/Users/tom/dev/gravatar2”

%w{8200 8201 8202}.each do |port|
God.watch do |w|
w.name = “gravatar2-mongrel-#{port}”
w.interval = 30.seconds # default
w.start = “mongrel_rails start -c #{RAILS_ROOT} -p #{port}
-P #{RAILS_ROOT}/log/mongrel.#{port}.pid -d”
w.stop = “mongrel_rails stop -P
w.restart = “mongrel_rails restart -P
w.start_grace = 10.seconds
w.restart_grace = 10.seconds
w.pid_file = File.join(RAILS_ROOT, “log/mongrel.#{port}.pid”)


w.start_if do |start|
  start.condition(:process_running) do |c|
    c.interval = 5.seconds
    c.running = false

w.restart_if do |restart|
  restart.condition(:memory_usage) do |c|
    c.above = 150.megabytes
    c.times = [3, 5] # 3 out of 5 intervals

  restart.condition(:cpu_usage) do |c|
    c.above = 50.percent
    c.times = 5

# lifecycle
w.lifecycle do |on|
  on.condition(:flapping) do |c|
    c.to_state = [:start, :restart]
    c.times = 5
    c.within = 5.minute
    c.transition = :unmonitored
    c.retry_in = 10.minutes
    c.retry_times = 5
    c.retry_within = 2.hours



Detailed documentation is available at http://god.rubyforge.org/


== 0.6.0 / 2007-12-4

  • Minor Enhancement
    • Move Syslog calls into God::Logger and clean up all calling code
    • Remove god’s pid file on user requested termination
    • Better handling and cleanup of DRb server’s unix domain socket
    • Allow shorthand for requesting a god log
    • Add god check to make it easier to diagnose event problems
    • Refactor god binary into class/method structure
    • Implement god remove to remove a Task altogether
  • New Conditions
    • DiskUsage < PollCondition - trigger if disk usage is above limit on
      mount [Rudy Desjardins]


Tom Preston-Werner
Kevin C.

Tom Preston-Werner

Looks very cool. I look forward to playing with it.

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