Process Monitoring Ruby - God

God est ce qu’on appelle un “process monitoring”, ou, en français, un processus dédié à la surveillance d’autres processus. Le principe est très simple : à intervalle régulier ou selon certains événements, God va analyser si les processus qu’il est chargé de surveiller sont toujours en cours d’exécution. Ca peut être en vérifiant la présence d’un fichier “pid” par exemple. Si le processus ne tourne plus, God va essayer de le relancer à plusieurs reprises jusqu’à ce que le processus soit de nouveau opérationnel.

Découvrons god

$ (sudo) gem install god

# simple.rb

loop do

	puts ‘Hello’

	sleep 1

end

# simple.god

God.watch do |w|

  w.name = "simple"

  w.start = "ruby /chemin/vers/simple.rb"

  w.keepalive

end

$ god -c chemin/vers/simple.god -D

$ sudo mkdir /var/run/god

I [2013-10-04 15:03:12]  INFO: Loading ./simple.god

I [2013-10-04 15:03:12]  INFO: Syslog enabled.

I [2013-10-04 15:03:12]  INFO: Using pid file directory: ~/.god/pids

I [2013-10-04 15:03:12]  INFO: Started on drbunix:///tmp/god.17165.sock

I [2013-10-04 15:03:12]  INFO: simple move 'unmonitored' to 'up'

I [2013-10-04 15:03:12]  INFO: simple moved 'unmonitored' to 'up'

I [2013-10-04 15:03:12]  INFO: simple [trigger] process is not running (ProcessRunning)

I [2013-10-04 15:03:12]  INFO: simple move 'up' to 'start'

I [2013-10-04 15:03:12]  INFO: simple start: ruby /chemin/vers/simple.rb

I [2013-10-04 15:03:12]  INFO: simple moved 'up' to 'up'

$ ps -Fe | grep simple.rb

$ sudo kill process_pid

I [2013-10-04 15:07:06]  INFO: simple [trigger] process is not running (ProcessRunning)

I [2013-10-04 15:07:06]  INFO: simple move 'up' to 'start'

I [2013-10-04 15:07:06]  INFO: simple start: ruby /chemin/vers/simple.rb

I [2013-10-04 15:07:06]  INFO: simple moved 'up' to 'up'

# simple.god

God.watch do |w|

  w.name = "simple"

  w.start = "ruby /full/path/to/simple.rb"

  w.keepalive(:memory_max => 150.megabytes,

              :cpu_max => 50.percent)

end

# simple.rb

data = ''

loop do

  puts 'Hello'

  100000.times { data << 'x' }

end

$ god restart simple

Sending 'restart' command



The following watches were affected:

  simple

I [2011-12-07 14:54:37]  INFO: simple [ok] process is running (ProcessRunning)

I [2011-12-07 14:54:37]  INFO: simple [ok] memory within bounds [2032kb] (MemoryUsage)

I [2011-12-07 14:54:37]  INFO: simple [ok] cpu within bounds [0.0%%] (CpuUsage)

I [2011-12-07 14:54:42]  INFO: simple [ok] process is running (ProcessRunning)

I [2011-12-07 14:54:42]  INFO: simple [ok] memory within bounds [2032kb, 13492kb] (MemoryUsage)

I [2011-12-07 14:54:42]  INFO: simple [ok] cpu within bounds [0.0%%, *99.7%%] (CpuUsage)

I [2011-12-07 14:54:47]  INFO: simple [ok] process is running (ProcessRunning)

I [2011-12-07 14:54:47]  INFO: simple [ok] memory within bounds [2032kb, 13492kb, 25568kb] (MemoryUsage)

I [2011-12-07 14:54:47]  INFO: simple [ok] cpu within bounds [0.0%%, *99.7%%, *100.0%%] (CpuUsage)

I [2011-12-07 14:54:52]  INFO: simple [ok] process is running (ProcessRunning)

I [2011-12-07 14:54:52]  INFO: simple [ok] memory within bounds [2032kb, 13492kb, 25568kb, 37556kb] (MemoryUsage)

I [2011-12-07 14:54:52]  INFO: simple [trigger] cpu out of bounds [0.0%%, *99.7%%, *100.0%%, *98.4%%] (CpuUsage)

I [2011-12-07 14:54:52]  INFO: simple move 'up' to 'restart'

God et Delayed Jobs

ENV = “production”

if ENV == "production"

  PROJECTS_ROOT = “/var/www/”

  application_root = "#{PROJECTS_ROOT}/application.fr"

  application_shared_root = application_root

else

  PROJECTS_ROOT = “/home/user/RailsWorkspace”

  application_root = "#{PROJECTS_ROOT}/ActualProjectsWorkspace/application"

  application_shared_root = application_root

end



God.watch do |w|

  w.name = "application-delayed-job"

  w.group = "application"

  w.interval = 1.minute



  w.start = "/bin/bash -c 'cd #{application_root}; /usr/bin/env RAILS_ENV=#{ENV} script/delayed_job start > /tmp/application_delay_job.out'"

  w.stop = "/bin/bash -c 'cd #{application_root}; /usr/bin/env RAILS_ENV=#{ENV} script/delayed_job stop'"



  w.log = "#{application_shared_root}/log/god_delayed_job.log"

  w.start_grace = 30.seconds

  w.restart_grace = 30.seconds



  w.pid_file = File.join(application_shared_root, "tmp/pids/delayed_job.pid")



  w.behavior(:clean_pid_file)



  w.start_if do |start|

     start.condition(:process_running) do |c|

        c.interval = 15.seconds

        c.running = false

     end

  end



  w.restart_if do |restart|

	restart.condition(:memory_usage) do |c|

  	   c.above = 150.megabytes

       c.times = [3,5]

	end

	restart.condition(:cpu_usage) do |c|

   	   c.above = 30.percent

       c.times = 8

	end

  end



  w.lifecycle do |on|

	on.condition(:flapping) do |c|

  	   c.to_state = [:start, :restart]

       c.times = 5

       c.within = 10.minute

       c.transition = :unmonitored

       c.retry_in = 10.minutes

       c.retry_times = 5

       c.retry_within = 2.hours

	end

  end

end

ENV = “production”

if ENV == "production"

  PROJECTS_ROOT = “/var/www/”

  application_root = "#{PROJECTS_ROOT}/application.fr"

  application_shared_root = application_root

else

  PROJECTS_ROOT = “/home/user/RailsWorkspace”

  application_root = "#{PROJECTS_ROOT}/ActualProjectsWorkspace/application"

  application_shared_root = application_root

end

God.watch do |w|

  w.name = "application-delayed-job"

  w.group = "application"

  w.interval = 1.minute

$ god restart group_name (ici “application”)

  w.start = "/bin/bash -c 'cd #{application_root}; /usr/bin/env RAILS_ENV=#{ENV} script/delayed_job start > /tmp/application_delay_job.out'"

  w.stop = "/bin/bash -c 'cd #{application_root}; /usr/bin/env RAILS_ENV=#{ENV} script/delayed_job stop'"



  w.log = "#{application_shared_root}/log/god_delayed_job.log"

$ god stop application-delayed-job

  w.start_grace = 30.seconds

  w.restart_grace = 30.seconds



  w.pid_file = File.join(application_shared_root, "tmp/pids/delayed_job.pid")



  w.behavior(:clean_pid_file)

  w.start_if do |start|

	start.condition(:process_running) do |c|

  	c.interval = 15.seconds

  	c.running = false # Teste si le processus n'est plus en cours d'exécution - notez qu'il ne faut pas utiliser ==

	end

  end

  w.restart_if do |restart|

	restart.condition(:memory_usage) do |c|

  	c.above = 150.megabytes

  	c.times = [3,5]	end



	restart.condition(:cpu_usage) do |c|

  	c.above = 30.percent

  	c.times = 8

	end

  end

  w.lifecycle do |on|

	on.condition(:flapping) do |c|

  	c.to_state = [:start, :restart]  	c.times = 5

  	c.within = 10.minute

  	c.transition = :unmonitored

  	c.retry_in = 10.minutes

  	c.retry_times = 5

  	c.retry_within = 2.hours

	end

  end

Multi Rails App et God

# almighty.god

ENV = "production"



if ENV == "production"

  PROJECTS_ROOT = "/var/www/"

else

  PROJECTS_ROOT = "/home/user/RailsWorkspace"

end



load File.join(File.dirname(__FILE__), 'application1.fr', 'application1_tasks.god')

load File.join(File.dirname(__FILE__), 'application2.fr', 'application2_tasks.god')

load File.join(File.dirname(__FILE__), 'application3.com', 'application1_tasks.god')

$ god -c chemin/almighty.god

Linux et God

#!/bin/sh

# god init script

### BEGIN INIT INFO

# Provides:         	god

# Required-Start:   	$all

# Required-Stop:    	$all

# Default-Start:    	2 3 4 5

# Default-Stop:     	0 1 6

# Short-Description:	God

### END INIT INFO



# En local pour dev

#PATH=/home/user/.rvm/bin:/sbin:/bin:/usr/sbin:/usr/bin

#CONFIGFILE=/home/user/RailsWorkspace/all.god

#DAEMON=/home/user/.rvm/bin/boot_god



source /usr/local/rvm/environments/ruby-1.9.3-p385



#PATH=/usr/local/rvm/bin:/sbin:/bin:/usr/sbin:/usr/bin

DESC="God Monitoring Tool"

NAME=god

DAEMON=/usr/local/rvm/bin/boot_god

PIDFILE=/var/run/god.pid

LOGFILE=/var/log/god.log

SCRIPTNAME=/etc/init.d/god

CONFIGFILE=/var/www/almighty.god



#DEBUG_OPTIONS="--log-level [debug|info|warn|error|fatal]DEBUG_OPTIONS="--log-level debug"



# Exit if 'god' gem is not available

[ -x "$DAEMON" ] || (echo "God gem isn't available"; exit 0)



# Read configuration variable file if it is present

[ -r /etc/default/$NAME ] && . /etc/default/$NAME



# Load the VERBOSE setting and other rcS variables

. /lib/init/vars.sh



# Define LSB log_* functions.

# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.

. /lib/lsb/init-functions



RETVAL=0



case "$1" in

  start)

	echo -n "Starting $DESC: "

	$DAEMON -l $LOGFILE -P $PIDFILE $DEBUG_OPTIONS -c $CONFIGFILE

	RETVAL=$?

	echo "$NAME."

	;;

  stop)

	echo -n "Stopping $DESC: "

	$DAEMON terminate

	RETVAL=$?

	echo "$NAME."

	;;

  restart)

	echo -n "Restarting $DESC: "

	$DAEMON terminate

	$DAEMON -l $LOGFILE -P $PIDFILE $DEBUG_OPTIONS -c $CONFIGFILE

	RETVAL=$?

	echo "$NAME."

	;;

  status)

	$DAEMON status

	RETVAL=$?

	;;

  *)

	echo "Usage: god {start|stop|restart|status}"

	exit 1

	;;

esac



exit $RETVAL

$ which god

> path/to/god

$ ln -s path/to/god /usr/local/rvm/bin/boot_god

$ sudo chmod a+x god

$ sudo update-rc.d god defaults

$ sudo /etc/init.d/god start

# Et optionnellement : 

$ sudo ln -s /usr/local/rvm/bin/boot_god /usr/local/bin/god

# Pour ensuite pouvoir faire : 

$ sudo god restart my-process-name

Index -- Article précédent: Formation Ruby On Rails à Paris -- Article suivant: Terminal Bash et Git

• 
• Administration Système
• ruby on rails
• tutoriel