gistfile1.rb

#!/usr/local/bin/ruby
#
# watch for bloating passengers and kill them gracefully if possible (SIGUSR), then with extreme prejudice (SIGTERM)
#

require 'yaml'
require 'rubygems'
require 'syslog_logger'

logger = SyslogLogger.new("passenger")

# required by passenger
ENV['HTTPD'] = 'apache2'

WARN_MEM_LIMIT = ARGV[0] || 280
CRIT_MEM_LIMIT = ARGV[1] || 550

module Process
  def self.running?(pid)
    begin
      return Process.getpgid(pid) != -1
    rescue Errno::ESRCH
      return false
    end
  end
end

`/usr/local/bin/passenger-memory-stats`.each_line do |line|
  if line =~ /Rails: /
    parts = line.split
    pid, private_dirty_rss, path = parts[0].to_i, parts[4].to_f, parts[7]
    if private_dirty_rss > CRIT_MEM_LIMIT.to_i
      logger.info "Found process #{pid} with critical size #{private_dirty_rss.to_s} at path #{path}"
      logger.info "Attempting graceful kill with SIGUSR1..."
      Process.kill("SIGUSR1", pid)
      logger.info "Finished kill attempt. Sleeping for 10 seconds..."
      sleep 10
      if Process.running?(pid)
        logger.info "Process #{pid} is still running. Killing with extreme predjudice (SIGTERM)!"
        Process.kill("TERM", pid)
      end
      logger.info "Done."
    elsif private_dirty_rss > WARN_MEM_LIMIT.to_i
      logger.info "Found process #{pid} with size #{private_dirty_rss.to_s} at path #{path}"
      logger.info "Gracefully killing with SIGUSR1..."
      Process.kill("SIGUSR1", pid)
      logger.info "Done."
    end
  end
end

line 1 and 28 need to be updated in order to get this working