cvs.andrew.net.au/presentations/nagios.mgp

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% This default.mgp is "TrueType fonts" oriented.
%% First, you should create "~/.mgprc" whose contents are:
%%	tfdir "/path/to/truetype/fonts"
%%
%% To visualize English, install "times.ttf", "arial.ttf", and "cour.ttf"
%% into the "tfdir" directory above:
%%	http://microsoft.com/typography/fontpack/default.htm
%%
%% To visualize Japanese, install "MSMINCHO.ttf" and 
%% "watanabenabe-mincho.ttf" into the "tfdir" directory above:
%%	http://www.mew.org/mgp/xtt-fonts_0.19981020-3.tar.gz
%%
%deffont "standard" xfont "helvetica-medium-r", tfont "standard.ttf", tmfont "hoso6.ttf"
%deffont "thick" xfont "helvetica-bold-r", tfont "thick.ttf", tmfont "hoso6.ttf"
%deffont "typewriter" xfont "courier-medium-r", tfont "typewriter.ttf", tmfont "hoso6.ttf"
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%%
%% Default settings per each line numbers.
%%
%default 1 area 90 90, leftfill, size 2, fore "gray20", back "white", font "standard", hgap 0
%default 2 size 7, vgap 10, prefix " ", ccolor "black"
%default 3 size 2, bar "gray70", vgap 10
%default 4 size 5, fore "gray20", vgap 30, prefix " ", font "standard"
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Default settings that are applied to TAB-indented lines.
%%
%tab 1 size 5, vgap 40, prefix "  ", icon box "green" 50
%tab 2 size 4, vgap 40, prefix "      ", icon arc "yellow" 50
%tab 3 size 3, vgap 40, prefix "            ", icon delta3 "white" 40
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%page
%nodefault
%size 6.5, font "standard", back "white", ccolor "black"


%center, fore "Blue", font "standard", hgap 60, size 6.5
An introduction to Nagios
%bar "skyblue" 6 15 70
%font "standard", hgap 0
%image "logofullsize.png"


%size 5, fore "darkblue"
Andrew Pollock
%size 4.5
me@andrew.net.au

%size 1.5
Nagios and Nagios logo are registered trademarks of Ethan Galstad

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page
%bgrad 0 0 256 0 0 "white" "blue"

Overview 

	Theory of operation
	Configuration files
	Plugins

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page
%bgrad 0 0 256 0 0 "white" "blue"

Theory of operation 

	Central monitoring server
	Hard and soft service statuses
	Service check scheduling
	Dependencies


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page

Nagios just schedules plugin execution

%CENTER
%IMAGE "plugintheory.png"

It has no real idea of what you're monitoring, just the results of the plugin
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page
%bgrad 0 0 256 0 0 "white" "blue"

State types

The current state of a service or host check is determined by the status of the check and the type the state is in.
	Soft states
		Check result is non-OK and not yet been rerun the configured number of times for it to go into a hard state
		If the check recovers before going to the hard state it is a soft recovery
		Completely optional (set max_check_attempts to 0)
	Hard states
		Repeated (max_check_attempts) checks have returned non-OK
		If the check recovers, it is a hard recovery

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page
%bgrad 0 0 256 0 0 "white" "blue"

Scheduling

	Service checks can be individually scheduled
		Frequency of execution
		Frequency and quantity of rechecks on failure

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page
%bgrad 0 0 256 0 0 "white" "blue"

Dependencies

Hosts have a concept of parents
If a host goes down, any other hosts that have it as a parent are considered unreachable and therefore in an unknown state.

Proper configuration of hierarchy will allow for a reasonable logical diagram to be automatically constructed

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%page

Hierarchy example

%CENTER
%IMAGE "physical-network.png"

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Configuration files

	nagios.cfg
		Main configuration file
		"Includes" addition configuration files to provide logical separation
	hosts.cfg
		Defines your hosts
	services.cfg
		Defines the services checked
	commands.cfg
		Defines what a command actually is
	resource.cfg
		Defines macros/variables you can use in other config files

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Configuration files

You can end up with too much logical separation. 

There's no reason not to merge hosts.cfg and services.cfg if it makes sense in your environment.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

A walk through nagios.cfg

	log_file
		Specifies where the main logfile should go
	cfg_file
		"Includes" additional files as configuration files
		cfg_file=/opt/local/nagios/etc/hosts.cfg
		cfg_file=/opt/local/nagios/etc/services.cfg
		cfg_file=/opt/local/nagios/etc/commands.cfg
		This is where you can merge files if it all gets too distributed
	cfg_dir
		Will read all .cfg files as config files as per above
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

nagios.cfg (continued)

	resource_file
		Defines macros/variables
		Macros are not expanded when the configuration is viewed via the web interface
		Allows you to protect sensitive values like passwords
		Can be used multiple times to specify multiple files
	host_check_timeout & service_check_timeout
		Global setting for maximum number of seconds a plugin execution can run for before it considered to have timed out
		Can be adjusted on a per-service basis

Plenty of other options you're not likely to need to tweak. See the documentation for more information.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Object configuration files

	What is object data?
		Services
		Hosts
		Host groups
		Contacts
		Contact groups
		Commands
		Time Periods
		Service Escalations
		Service Dependencies
		Host Escalations
		Host Dependencies
		Hostgroup Escalations
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Object configuration files (continued)

	Has a template based system that supports inheritance
		Makes "carbon-copy" services easy to maintain
		Reduces the size and complexity of your configuration files

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Host Definitions

	Used to define a physical device on the network
	A host has services
%size 2
define host{
%fore "red"
        host_name	host_name
        alias	alias 
        address address 
%fore "black"
        parents	host_names 
        check_command command_name 
%fore "red"
        max_check_attempts 	# 
%fore "black"
        checks_enabled	[0/1] 
        event_handler	command_name 
        event_handler_enabled	[0/1] 
        low_flap_threshold	# 
        high_flap_threshold	# 
        flap_detection_enabled	[0/1] 
        process_perf_data	[0/1] 
        retain_status_information	[0/1] 
        retain_nonstatus_information	[0/1] 
%fore "red"
        notification_interval	# 
        notification_period	timeperiod_name 
        notification_options	[d,u,r] 
%fore "black"
        notifications_enabled	[0/1] 
        stalking_options	[o,d,u]
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Service Definitions

	A service runs on a host
	Can be a network service or any other metric you want to associate with a host

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Service Definitions (continued)

%size 2
define service{ 
%fore "red"
        host_name	host_name 
        service_description	service_description 
%fore "black"
        is_volatile	[0/1] 
%fore "red"
        check_command	command_name 
        max_check_attempts	# 
        normal_check_interval	# 
        retry_check_interval	# 
%fore "black"
        active_checks_enabled	[0/1] 
        passive_checks_enabled	[0/1] 
%fore "red"
        check_period	timeperiod_name 
%fore "black"
        parallelize_check	[0/1] 
        obsess_over_service	[0/1] 
        check_freshness	[0/1] 
        freshness_threshold	# 
        event_handler	command_name 
        event_handler_enabled	[0/1] 
        low_flap_threshold	# 
        high_flap_threshold	# 
        flap_detection_enabled	[0/1] 
        process_perf_data	[0/1] 
        retain_status_information	[0/1] 
        retain_nonstatus_information	[0/1] 
%fore "red"
        notification_interval	# 
        notification_period	timeperiod_name 
        notification_options	[w,u,c,r] 
%fore "black"
        notifications_enabled	[0/1] 
%fore "red"
        contact_groups	contact_groups 
%fore "black"
        stalking_options	[o,w,u,c]    
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Command Definitions

	Maps a command name within Nagios to an operating system command to execute
	Can use macros defined in resources.cfg as well as special context sensitive variables

%size 2
define command{
%fore "red"
        command_name	command_name
        command_line	command_line
%fore "black"
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Templates allow inheritance

	They simplify what you need to specify in an inherited object
	They allow for default values to specified once, globally, but override on a case-by-case basis if required

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Inheritance example

%size 2
define host{
        check_command		check-host-alive
        notification_options	d,u,r
        max_check_attempts	5
%fore "red"
        name			generichosttemplate
        register			0
%fore "black"
}

define host{
        host_name		bighost1
        address			192.168.1.3
%fore "red"
        use			generichosthosttemplate
%fore "black"
}

define host{
        host_name		bighost2
        address			192.168.1.4
%fore "red"
        use			generichosthosttemplate
%fore "black"
}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Saving time

Same service, multiple hosts:

%size 2
define service{
%fore "red"
        host_name	HOST1,HOST2,HOST3
        service_description	SOMESERVICEICOOKEDUP
%fore "black"
        ...
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Service checks - active vs passive

	Active checks
		Scheduled and executed by Nagios
	Passive checks
		Run externally to Nagios and submit results back
		Can use the freshness threshold to ensure results are being submitted frequently enough

Generally checks are active, but under certain circumstances you have to use passive checks (e.g. Nagios can't access the service itself, but it can tell Nagios how it's going)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Plugins

%size 4
	Provide the actual monitoring power of Nagios
%size 4
	Can do whatever you want
%size 4
	Write them in whatever takes your fancy
%size 4
	All they have to do is return one line of output (on STDOUT) and an return code ($?)
%size 4
		0 = OK
%size 4
		1 = WARNING
%size 4
		2 = CRITICAL
%size 4
		3 (or anything else) = UNKNOWN
%size 4
	Nagios comes with a whole stack of standard plugins that will check most of the things you'd want to check
%size 4
	Normally run by the nagios user, so run unprivileged
%size 4
	Run locally directly by the nagios process or remotely usually by the check_by_ssh plugin

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Plugin examples

%size 4
\#!/bin/sh

echo "All is quiet on the western front"
exit 0

\#!/usr/bin/perl

print "Everything's busted!\n";
exit(2);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%PAGE
%bgrad 0 0 256 0 0 "white" "blue"

Further reading

	http://www.nagios.org
	http://nagiosplug.sourceforge.net

Questions?
1	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2	%%
3	%% This default.mgp is "TrueType fonts" oriented.
4	%% First, you should create "~/.mgprc" whose contents are:
5	%% tfdir "/path/to/truetype/fonts"
6	%%
7	%% To visualize English, install "times.ttf", "arial.ttf", and "cour.ttf"
8	%% into the "tfdir" directory above:
9	%% http://microsoft.com/typography/fontpack/default.htm
10	%%
11	%% To visualize Japanese, install "MSMINCHO.ttf" and
12	%% "watanabenabe-mincho.ttf" into the "tfdir" directory above:
13	%% http://www.mew.org/mgp/xtt-fonts_0.19981020-3.tar.gz
14	%%
15	%deffont "standard" xfont "helvetica-medium-r", tfont "standard.ttf", tmfont "hoso6.ttf"
16	%deffont "thick" xfont "helvetica-bold-r", tfont "thick.ttf", tmfont "hoso6.ttf"
17	%deffont "typewriter" xfont "courier-medium-r", tfont "typewriter.ttf", tmfont "hoso6.ttf"
18	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19	%%
20	%% Default settings per each line numbers.
21	%%
22	%default 1 area 90 90, leftfill, size 2, fore "gray20", back "white", font "standard", hgap 0
23	%default 2 size 7, vgap 10, prefix " ", ccolor "black"
24	%default 3 size 2, bar "gray70", vgap 10
25	%default 4 size 5, fore "gray20", vgap 30, prefix " ", font "standard"
26	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
27	%%
28	%% Default settings that are applied to TAB-indented lines.
29	%%
30	%tab 1 size 5, vgap 40, prefix " ", icon box "green" 50
31	%tab 2 size 4, vgap 40, prefix " ", icon arc "yellow" 50
32	%tab 3 size 3, vgap 40, prefix " ", icon delta3 "white" 40
33	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
34	%page
35	%nodefault
36	%size 6.5, font "standard", back "white", ccolor "black"
37
38
39
40
41
42	%center, fore "Blue", font "standard", hgap 60, size 6.5
43	An introduction to Nagios
44	%bar "skyblue" 6 15 70
45	%font "standard", hgap 0
46	%image "logofullsize.png"
47
48
49	%size 5, fore "darkblue"
50	Andrew Pollock
51	%size 4.5
52	me@andrew.net.au
53
54	%size 1.5
55	Nagios and Nagios logo are registered trademarks of Ethan Galstad
56
57	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
58	%page
59	%bgrad 0 0 256 0 0 "white" "blue"
60
61	Overview
62
63	Theory of operation
64	Configuration files
65	Plugins
66
67	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
68	%page
69	%bgrad 0 0 256 0 0 "white" "blue"
70
71	Theory of operation
72
73	Central monitoring server
74	Hard and soft service statuses
75	Service check scheduling
76	Dependencies
77
78
79
80	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
81	%page
82
83	Nagios just schedules plugin execution
84
85	%CENTER
86	%IMAGE "plugintheory.png"
87
88	It has no real idea of what you're monitoring, just the results of the plugin
89	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
90	%page
91	%bgrad 0 0 256 0 0 "white" "blue"
92
93	State types
94
95	The current state of a service or host check is determined by the status of the check and the type the state is in.
96	Soft states
97	Check result is non-OK and not yet been rerun the configured number of times for it to go into a hard state
98	If the check recovers before going to the hard state it is a soft recovery
99	Completely optional (set max_check_attempts to 0)
100	Hard states
101	Repeated (max_check_attempts) checks have returned non-OK
102	If the check recovers, it is a hard recovery
103
104	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
105	%page
106	%bgrad 0 0 256 0 0 "white" "blue"
107
108	Scheduling
109
110	Service checks can be individually scheduled
111	Frequency of execution
112	Frequency and quantity of rechecks on failure
113
114	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
115	%page
116	%bgrad 0 0 256 0 0 "white" "blue"
117
118	Dependencies
119
120	Hosts have a concept of parents
121	If a host goes down, any other hosts that have it as a parent are considered unreachable and therefore in an unknown state.
122
123	Proper configuration of hierarchy will allow for a reasonable logical diagram to be automatically constructed
124
125	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
126	%page
127
128	Hierarchy example
129
130	%CENTER
131	%IMAGE "physical-network.png"
132
133	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
134	%PAGE
135	%bgrad 0 0 256 0 0 "white" "blue"
136
137	Configuration files
138
139	nagios.cfg
140	Main configuration file
141	"Includes" addition configuration files to provide logical separation
142	hosts.cfg
143	Defines your hosts
144	services.cfg
145	Defines the services checked
146	commands.cfg
147	Defines what a command actually is
148	resource.cfg
149	Defines macros/variables you can use in other config files
150
151	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
152	%PAGE
153	%bgrad 0 0 256 0 0 "white" "blue"
154
155	Configuration files
156
157	You can end up with too much logical separation.
158
159	There's no reason not to merge hosts.cfg and services.cfg if it makes sense in your environment.
160
161	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
162	%PAGE
163	%bgrad 0 0 256 0 0 "white" "blue"
164
165	A walk through nagios.cfg
166
167	log_file
168	Specifies where the main logfile should go
169	cfg_file
170	"Includes" additional files as configuration files
171	cfg_file=/opt/local/nagios/etc/hosts.cfg
172	cfg_file=/opt/local/nagios/etc/services.cfg
173	cfg_file=/opt/local/nagios/etc/commands.cfg
174	This is where you can merge files if it all gets too distributed
175	cfg_dir
176	Will read all .cfg files as config files as per above
177	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
178	%PAGE
179	%bgrad 0 0 256 0 0 "white" "blue"
180
181	nagios.cfg (continued)
182
183	resource_file
184	Defines macros/variables
185	Macros are not expanded when the configuration is viewed via the web interface
186	Allows you to protect sensitive values like passwords
187	Can be used multiple times to specify multiple files
188	host_check_timeout & service_check_timeout
189	Global setting for maximum number of seconds a plugin execution can run for before it considered to have timed out
190	Can be adjusted on a per-service basis
191
192	Plenty of other options you're not likely to need to tweak. See the documentation for more information.
193
194	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
195	%PAGE
196	%bgrad 0 0 256 0 0 "white" "blue"
197
198	Object configuration files
199
200	What is object data?
201	Services
202	Hosts
203	Host groups
204	Contacts
205	Contact groups
206	Commands
207	Time Periods
208	Service Escalations
209	Service Dependencies
210	Host Escalations
211	Host Dependencies
212	Hostgroup Escalations
213	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
214	%PAGE
215	%bgrad 0 0 256 0 0 "white" "blue"
216
217	Object configuration files (continued)
218
219	Has a template based system that supports inheritance
220	Makes "carbon-copy" services easy to maintain
221	Reduces the size and complexity of your configuration files
222
223	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
224	%PAGE
225	%bgrad 0 0 256 0 0 "white" "blue"
226
227	Host Definitions
228
229	Used to define a physical device on the network
230	A host has services
231	%size 2
232	define host{
233	%fore "red"
234	host_name host_name
235	alias alias
236	address address
237	%fore "black"
238	parents host_names
239	check_command command_name
240	%fore "red"
241	max_check_attempts #
242	%fore "black"
243	checks_enabled [0/1]
244	event_handler command_name
245	event_handler_enabled [0/1]
246	low_flap_threshold #
247	high_flap_threshold #
248	flap_detection_enabled [0/1]
249	process_perf_data [0/1]
250	retain_status_information [0/1]
251	retain_nonstatus_information [0/1]
252	%fore "red"
253	notification_interval #
254	notification_period timeperiod_name
255	notification_options [d,u,r]
256	%fore "black"
257	notifications_enabled [0/1]
258	stalking_options [o,d,u]
259	}
260
261	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
262	%PAGE
263	%bgrad 0 0 256 0 0 "white" "blue"
264
265	Service Definitions
266
267	A service runs on a host
268	Can be a network service or any other metric you want to associate with a host
269
270	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
271	%PAGE
272	%bgrad 0 0 256 0 0 "white" "blue"
273
274	Service Definitions (continued)
275
276	%size 2
277	define service{
278	%fore "red"
279	host_name host_name
280	service_description service_description
281	%fore "black"
282	is_volatile [0/1]
283	%fore "red"
284	check_command command_name
285	max_check_attempts #
286	normal_check_interval #
287	retry_check_interval #
288	%fore "black"
289	active_checks_enabled [0/1]
290	passive_checks_enabled [0/1]
291	%fore "red"
292	check_period timeperiod_name
293	%fore "black"
294	parallelize_check [0/1]
295	obsess_over_service [0/1]
296	check_freshness [0/1]
297	freshness_threshold #
298	event_handler command_name
299	event_handler_enabled [0/1]
300	low_flap_threshold #
301	high_flap_threshold #
302	flap_detection_enabled [0/1]
303	process_perf_data [0/1]
304	retain_status_information [0/1]
305	retain_nonstatus_information [0/1]
306	%fore "red"
307	notification_interval #
308	notification_period timeperiod_name
309	notification_options [w,u,c,r]
310	%fore "black"
311	notifications_enabled [0/1]
312	%fore "red"
313	contact_groups contact_groups
314	%fore "black"
315	stalking_options [o,w,u,c]
316	}
317
318	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
319	%PAGE
320	%bgrad 0 0 256 0 0 "white" "blue"
321
322	Command Definitions
323
324	Maps a command name within Nagios to an operating system command to execute
325	Can use macros defined in resources.cfg as well as special context sensitive variables
326
327	%size 2
328	define command{
329	%fore "red"
330	command_name command_name
331	command_line command_line
332	%fore "black"
333	}
334
335	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
336	%PAGE
337	%bgrad 0 0 256 0 0 "white" "blue"
338
339	Templates allow inheritance
340
341	They simplify what you need to specify in an inherited object
342	They allow for default values to specified once, globally, but override on a case-by-case basis if required
343
344	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
345	%PAGE
346	%bgrad 0 0 256 0 0 "white" "blue"
347
348	Inheritance example
349
350	%size 2
351	define host{
352	check_command check-host-alive
353	notification_options d,u,r
354	max_check_attempts 5
355	%fore "red"
356	name generichosttemplate
357	register 0
358	%fore "black"
359	}
360
361	define host{
362	host_name bighost1
363	address 192.168.1.3
364	%fore "red"
365	use generichosthosttemplate
366	%fore "black"
367	}
368
369	define host{
370	host_name bighost2
371	address 192.168.1.4
372	%fore "red"
373	use generichosthosttemplate
374	%fore "black"
375	}
376
377
378	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
379	%PAGE
380	%bgrad 0 0 256 0 0 "white" "blue"
381
382	Saving time
383
384	Same service, multiple hosts:
385
386	%size 2
387	define service{
388	%fore "red"
389	host_name HOST1,HOST2,HOST3
390	service_description SOMESERVICEICOOKEDUP
391	%fore "black"
392	...
393	}
394
395	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
396	%PAGE
397	%bgrad 0 0 256 0 0 "white" "blue"
398
399	Service checks - active vs passive
400
401	Active checks
402	Scheduled and executed by Nagios
403	Passive checks
404	Run externally to Nagios and submit results back
405	Can use the freshness threshold to ensure results are being submitted frequently enough
406
407	Generally checks are active, but under certain circumstances you have to use passive checks (e.g. Nagios can't access the service itself, but it can tell Nagios how it's going)
408
409	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
410	%PAGE
411	%bgrad 0 0 256 0 0 "white" "blue"
412
413	Plugins
414
415	%size 4
416	Provide the actual monitoring power of Nagios
417	%size 4
418	Can do whatever you want
419	%size 4
420	Write them in whatever takes your fancy
421	%size 4
422	All they have to do is return one line of output (on STDOUT) and an return code ($?)
423	%size 4
424	0 = OK
425	%size 4
426	1 = WARNING
427	%size 4
428	2 = CRITICAL
429	%size 4
430	3 (or anything else) = UNKNOWN
431	%size 4
432	Nagios comes with a whole stack of standard plugins that will check most of the things you'd want to check
433	%size 4
434	Normally run by the nagios user, so run unprivileged
435	%size 4
436	Run locally directly by the nagios process or remotely usually by the check_by_ssh plugin
437
438	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
439	%PAGE
440	%bgrad 0 0 256 0 0 "white" "blue"
441
442	Plugin examples
443
444	%size 4
445	\#!/bin/sh
446
447	echo "All is quiet on the western front"
448	exit 0
449
450	\#!/usr/bin/perl
451
452	print "Everything's busted!\n";
453	exit(2);
454
455	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
456	%PAGE
457	%bgrad 0 0 256 0 0 "white" "blue"
458
459	Further reading
460
461	http://www.nagios.org
462	http://nagiosplug.sourceforge.net
463
464	Questions?