The document discusses the Sensu monitoring system, detailing its architecture, installation, and components such as Sensu server and client. It highlights the use of checks and metrics, as well as the integration with various tools and plugins. Additionally, it covers configuration methods, event handling, and community support resources.

1. #monitoringlove
with Sensu
OSMC 2014, Nuremberg,
Germany

2. http://sensuapp.org

3. Why Sensu?
• Written in clean Ruby
• Scalable architecture
• Plugins in any language
• Can use Nagios checks
• Collects both checks and metrics
• Great community

4. Jochen Lillich
http://freistil.it
@geewiz

5. Sensu Core

6. Sensu Enterprise

7. Installation
• Omnibus packaging
• Configuration in JSON files
• Sensu cookbook for Chef
• Puppet module

10. • Connects all Sensu components
• Asynchronous communication

11. Sensu Server
• Orchestrates check execution
• Processes check results
• Triggers event handlers

12. Sensu Client
• Registers automatically with the Server
• Sends keepalive information
• Receives check execution requests
• Schedules checks locally
• Executes checks
• Publishes check results
• Publishes external events

13. API
• get event data
• get agent data
• trigger check execution
• resolve events
• silence checks

14. Dashboard
• Uchiwa
• sensu-admin

16. Scheduling
• Standard checks (server)
• Standalone checks (client)
• Manual checks (API)

17. {
"checks": {
"disk_free": {
"type": "status",
"subscribers": [ "all" ],
"handlers": [ "default" ],
"command": "/usr/lib/nagios/plugins/check_disk
-w :::disk_warn::: -c :::disk_crit:::
-A -x /dev/shm -X nfs -i /boot",
"interval": 60
}
}
}

18. Checks in Chef
sensu_check 'mysql_server' do
command "/usr/lib/nagios/plugins/check_mysql " +
"-u 'monitoring' " +
"-p '#{node['mysql']['server_mon_password']}'"
handlers ['default']
standalone true
interval 30
end

19. Metrics check
{
"checks": {
"load_metrics": {
"type": "metric",
"command": "load-metrics.rb",
"subscribers": [
"production"
],
"interval": 10
}
}
}

20. Metrics output
$ ruby load-metrics.rb
srv3.local.load_avg.one 0.89 1365270842
srv3.local.load_avg.five 1.01 1365270842
srv3.local.load_avg.fifteen 1.06 1365270842
$ echo $?
0

21. External events
echo '{ "name": "my_check",
"output": "some output",
"status": 0 }'
> /dev/tcp/localhost/3030
Useful: https://github.com/solarkennedy/sensu-shell-helper

23. Handler types
• Pipe
• TCP
• UDP
• Transport
• Sets

24. Common event handlers
• Email
• PagerDuty
• Graphite
• IRC
• Slack

26. Example handler code
#!/usr/bin/env ruby
require 'rubygems'
require 'json'
# Read event data
event = JSON.parse(STDIN.read, :symbolize_names => true)
# Write the event data to a file
file_name = "/tmp/sensu_#{event[:client][:name]}_" +
"#{event[:check][:name]}"
File.open(file_name, 'w') do |file|
file.write(JSON.pretty_generate(event))
end

27. Example handler configuration
{
"handlers": {
"file": {
"type": "pipe",
"command": "/etc/sensu/handlers/file.rb"
}
}
}

28. Sensu CLI
https://github.com/agent462/sensu-cli
• sensu-cli resolve srv3 apache_http
• sensu-cli client delete srv3
• sensu-cli silence srv3 --reason "Shut up already"
--expire 3600

29. #chatops
https://github.com/sensu/sensu-hubot
• sensu events summarize
• sensu events filter severity critical
• sensu events filter subscription webservers

30. Monitoring your monitoring
• Check RabbitMQ ready queue!

31. Scaling Sensu

32. Scaling a single site
• Sensu Server
• Sensu API
• RabbitMQ
• Redis

33. Multi-DC operation

37. HA
• High availability monitoring with Sensu

38. References

39. Community plugins
https://github.com/sensu/sensu-community-plugins
• Over 600 plugins
• 80 contributors

40. Support
• #sensu on FreeNode IRC
• sensu-users mailing list
• Commercial support from HeavyWater

41. Thank you!
@geewiz
jochen@freistil.it

42. Credits
• Samuel Beckett Bridge by Miguel Mendez https://flic.kr/p/
dyn2FU