1. What is nagios?
Version 2 8/
M.A.Newhall

2. History Rewrite/replacement for netsaint 1999 Popular fork Icinga 2009
Licence - GPL

3. Dual engine
monitoring engine
escalation engine

4. Is nagios for you? You? Can you be an open source advocate?
Become computer scientist.

5. Computer science Promises and contracts vs data and testing
Open source is computer science
Get in the authors head.
Experiment, test, program, solve, establish best practices
Don't assume anything works!

6. Why open source? Huge pool of pre written checks.
Search engine penetration?- outstanding
Support $1650-$4750
5 incident phone $1000

7. Upside No upgrade treadmill. Keep ahead of events. 'On it'
Integration with everything
web interface
tiered user interaction, directory authentication, whitelist, blacklist, etc.
Customizable

9. Downside Tons of decisions to be made
Decisions best recorded in config files
No server side automation
Self discipline

10. Organization
self discipline
inheritance
bogus hosts and groups.

11. Are your customers realistic?
When to page?
Reliability?

12. Beep frequency and escalation
1. Who - contact group or contact
2. When - timeperiods
3. How - ? beep? Hack power grid?
4. How often? - How many trys, how often to retries, rebeep?
5. Acceleration (escalation) - Speed up, slow down, beep someone new.

13. What is Nagios good at?
Watch systems - Web interface with user definable views and many ways to drill down and sort data
Remote alerts - You can beep/ /run scripts for any event with an frequency.

14. Not so good - Monitoring
Cacti

15. Targets? Network stack Linux systems OSX systems Windows systems
Log servers - (syslogd,eventviewer,splunk,etc)
Everything

16. Redundancy? Why? vms vs hardware vs what datacenter?
Examine and test example. - my/postgresql backend.

17. Software
Nagios
Nagios-plugins
Web server
Mail server

18. Install
Windows? Beta
Linux? Mature

19. Picking right Linux
Redhat
Centos
Fedora
Debian
Ubuntu

20. Automation Windows? - sorry don't know
Linux client deploy - yes! - Ansible,Puppet,Chef, etc
Linux Nagios server deploy - homegrown.

21. Install on Linux .rpm/.deb apt-get install nagios yum install nagios
cd someplace; tar xzvf nagios-VERSION.tar.gz
cd nagios
./config; make ; make install

22. Installing web server.
apt-get or yum
Apache https
nginx https

23. Mail server.
yum install postfix
Test
mail -S test

24. Clients
NRPE
NSCLIENT++
Nageventlog
SNMP
SNMP server

25. NRPE startup
demon vs xinitd
systemd vs initscripts

26. Install plugins tar xzvf nagios-plugins-VERSION.tar.gz
cd nagios-plugins
./configure
make
make install

27. Find a check Review Install plugins
Search plugin repos for specific check
Write check (return values plus text output)

28. Server

29. Concepts parents escalation IP vs hostname templates flapping
Inheritance

30. Core conf files
Cgi.cfg
nagios.cfg

31. core conf files (typically .cfg files)
hostgroups.cfg
hosts.cfg - Own directory (hosts)
define hostgroup{
hostgroup_name critical-linux
alias Critical Linux
contact_groups linux-admins,bean-counters
members example, example2, example3 }
define host{
use pingable-host
host_name example
Address
parents important-switch1 }

32. Additional conf files services.cfg define service{
use generic-service ; Name of service template to use
hostgroup_name critical-linux
service_description PING
is_volatile
check_period x7
max_check_attempts
normal_check_interval
retry_check_interval
contact_groups linux-admins
notification_interval
notification_period x7
notification_options w,u,c
check_command check_ping!100.0,20%!400.0,60% }

33. Additional conf files checkcommands.cfg contacts.cfg contactgroups.cfg
timeperiods.cfg
# 'check_ping' command definition
define command{
command_name check_ping
command_line $USER1$/check_ping -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -p 3 }

34. Accepting changes checking viability nagios service reload On fail...
nagios service restart
NAGIOSPATH/nagios -v /etc/nagios.cfg

35. git

36. Old samples
example-commands.txt

37. Questions?