Nagios Module 2

8/10/2019 Nagios Module 2

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GnuGroup InternationalGnuGrou

p International

NagiosN

agios

IT infrastructure monitoring toolIT infrastructure monitorin

g tool

ILGILGInsight GNU/Linux GroupIns

ight GNU/Linux Group

Reinventing the way you,Reinventing the way you,Think,Think,Learn,Learn,WorkWork


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NAGIOS

MODULE - 2


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Index of module - 2

External Commands

Event Handlers

Volatle Serv!es

"res#ness C#e!$s

State Stal$n%

"la&&n%

Usn% 'em&lates

O(e!t In#ertan!e

)assve C#e!$ *NSCA Clustern% - Dstr+uted

Montorn%

,edundant and "aloverNetor$ Montorn%

Na%os.L

Se!urt/ Consderatons


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External Commands

Na%os !an &ro!ess !ommandsfrom external a&&l!atons0n!ludn% t#e CGIs1 and altervarous as&e!ts of ts montorn%fun!tons +ased on t#e !ommandst re!eves

External a&&l!atons !an su+mt!ommands +/ rtn% to t#e!ommand fle3 #!# s&erod!all/ &ro!essed +/ t#e

Na%os daemon


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External CommandsEnabling External Commands

In order to #ave Na%os &ro!ess external !ommands3 ma$e sure /ou do t#e follon%4

Ena+le external !ommand !#e!$n% t# t#e !#e!$5external5!ommands o&ton

Set t#e fre6uen!/ of !ommand !#e!$s t# t#e !ommand5!#e!$5nterval o&ton

S&e!f/ t#e lo!aton of t#e !ommand fle t# t#e !ommand5fle o&ton

Setu& &ro&er &ermssons on t#e dre!tor/ !ontann% t#e external !ommand fle3 as des!r+ed n t#e 6u!$start%ude

When Does Nagios Check For External Commands

At re%ular ntervals s&e!fed +/ t#e !ommand5!#e!$5nterval o&ton n t#e man !onf%uraton fle

Immedatel/ after event #andlers are exe!uted '#s s n addton to t#e re%ular !/!le of external !ommand !#e!$sand s done to &rovde mmedate a!ton f an event #andler su+mts !ommands to Na%os

Using External Commands

External !ommands !an +e used to a!!om&ls# a varet/ of t#n%s #le Na%os s runnn% Exam&le of #at !an +e done n!lude tem&orarl/ dsa+ln% notf!atons for serv!es and #osts3 tem&orarl/

dsa+ln% serv!e !#e!$s3 for!n% mmedate serv!e !#e!$s3 addn% !omments to #osts and serv!es3 et!


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Event HandlersEvent #andlers are o&tonal s/stem !ommands 0s!r&ts or exe!uta+les1 t#at are run #enever a#ost or serv!e state !#an%e o!!urs

An o+vous use for event #andlers s t#e a+lt/ for Na%os to &roa!tvel/ fx &ro+lems +efore an/ones notfed Some ot#er uses for event #andlers n!lude4

,estartn% a faled serv!e

Entern% a trou+le t!$et nto a #el&des$ s/stem

Lo%%n% event nformaton to a data+ase

Et!

7#en Are Event Handlers Exe!uted8

Event #andlers are exe!uted #en a serv!e or #ost4

Is n a SO"' &ro+lem state

Intall/ %oes nto a HA,D &ro+lem state

Intall/ re!overs from a SO"' or HA,D &ro+lem state


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Event Handlers E!ent "andler #$pes

'#ere are dfferent t/&es of o&tonal event #andlers t#at /ou !an defne to #andle #ost and state !#an%es4

Glo+al #ost event #andler

Glo+al serv!e event #andler

Host-s&e!f! event #andlers

Serv!e-s&e!f! event #andlers

Enabling E!ent "andlersEvent #andlers !an +e ena+led or dsa+led on a &ro%ram-de +ass +/ usn% t#e ena+le5event5#andlers

n /our man !onf%uraton fle

Host- and serv!e-s&e!f! event #andlers !an +e ena+led or dsa+led +/ usn% t#e event5#andler5ena+led

dre!tve n /our #ost and serv!e defntons

Host- and serv!e-s&e!f! event #andlers ll not +eexe!uted f t#e %lo+al ena+le5event5#andlers o&ton s dsa+led


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Event HandlersExample o% E!ent "andlers

"ost %ile directi!edefne serv!e9

use lo!al-serv!e

#ost5name lo!al#ost

serv!e5des!r&ton daemons

!#e!$5!ommand !#e!$5nr&e:!#e!$5daemons

event5#andler restart&ser!ices

;In $our commands'c%g %ile( make sure $ou ha!e e!ent)handler de%ined something like*

defne !ommand9

!ommand5name restart&ser!ices

!ommand5lne *usr*lo!al*na%os*l+exe!*event#andlers*restart-serv!es ou sm&l/defne t#e tem&late as t#e re6uredo+(e!t t/&e '#e onl/ dfferen!e s t#at /ouneedto s&e!f/ t#e register directi!e andspeci%$ a !alue( o% :for t '#s ll tellNa%ost#at t s#ould not treat t#s as an a!tualo+(e!t3 +ut as a tem&late

defne someo+(e!tt/&e9o+(e!t-s&e!f! vara+les name template)nameuse name)o%)template)to)useregister A:/;B;


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O+(e!t In#ertan!e Fas!s

'#ere are three !ariables a%%ecting recursionand inheritancet#at are &resent n all o+(e!tdefntons

#he %irst !ariable is name' Its (ust a ?tem&late?name t#at !an +e referen!ed n ot#er o+(e!tdefntons so t#e/ !an n#ert t#e o+(e!ts&ro&ertes*vara+les 'em&late names must +e

un6ue amon%st o+(e!ts of t#e same t/&e3

#he second !ariable is use''#s s #ere /ous&e!f/ t#e name of t#e tem&late o+(e!t t#at /ouant to n#ert &ro&ertes*vara+les from '#ename /ou s&e!f/ for t#s vara+le must +edefned as anot#ero+(e!tBs tem&late named0usn% t#e name vara+le1

#he #hird( -egister( Defnn% tem&lates nNa%os s ver/ smlar to defnn% a!tual o+(e!ts>ou sm&l/defne t#e tem&late as t#e re6uredo+(e!t t/&e '#e onl/ dfferen!e s t#at /ouneedto s&e!f/ t#e register directi!e andspeci%$ a !alue( o% :for t '#s ll tellNa%ost#at t s#ould not treat t#s as an a!tualo+(e!t3 +ut as a tem&late

defne someo+(e!tt/&e9o+(e!t-s&e!f! vara+les name template)nameuse name)o%)template)to)useregister A:/;B;


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O+(e!t In#ertan!e


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)assve C#e!$ * NSCA

Anot#er %reat feature t#at Na%os offers s t#e a+lt/ for t#rd-&art/ softare orot#er Na%os nstan!es to re&ort nformaton on t#e status of serv!es or #osts

'#s a/3 Na%os does not need to s!#edule and run !#e!$s +/ tself3 +ut ot#era&&l!atons !an re&ort nformaton ast s avala+le to t#em

'#s means t#at /our a&&l!atons !an send &ro+lem re&orts dre!tl/ to Na%osnstead of (ust lo%%n% t#em

Na%os also offers a tool for sendn% &assve !#e!$ results for #osts and serv!esover a netor$ It s !alled NSCA 0Na%os Serv!e C#e!$ A!!e&tor1

It !an +e used to send results from one Na%os nstan!e to anot#er

'#s me!#ansm n!ludes &assord &rote!ton3 alon% t# en!r/&ton3 to&reventn(e!ton of false results n to Na%os In t#s a/3 NSCA !ommun!aton sentover Internet s more se!ure


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)assve C#e!$ * NSCA

'#ere are also dfferent t/&es of !#e!$s n!ludn% external a&&l!atons or dev!est#at ant to re&ort nformaton dre!tl/ to Na%os

'#s !an +e done to %at#er all !rt!al errors to a sn%le3 !entral &la!e '#ese t/&esof !#e!$s are !alled )assve C#e!$s

"or exam&le3 #en a e+ a&&l!aton !annot !onne!t to t#e data+ase3 t ll letNa%os $no a+out t mmedatel/

It !an also send re&orts after a data+ase re!over/3 or &erod!all/3 even f!onne!tvt/ to t#e data+ase #as +een !onsstentl/ avala+le3 so t#at Na%os #as anu&-to-date status

'#s !an +e done n addton to a!tve !#e!$s3to dentf/ !rt!al &ro+lems earler

Na%os also offers a a/ of !om+nn% t#e +enefts of +ot# a!tve and &assve!#e!$s


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)assve C#e!$ * NSCA

'#e frst t#n% t#at needs to +e done n order to use &assve !#e!$s for /our Na%ossetu& s to ma$e sure t#at /ou #ave t#e follon% o&tons n /our man Na%os!onf%uraton fle4

accept)passi!e)ser!ice)checks1;

accept)passi!e)host)checks1;

It ould also +e %ood to ena+le t#e lo%%n% of n!omn% &assve !#e!$s

'#s ma$es determnn% t#e &ro+lem of not &ro!essn% a &assve !#e!$ mu!#easer '#e follon% dre!tve allos t4

log)passi!e)checks1;


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)assve C#e!$ * NSCA +etting up hosts or ser!ices %or passi!e

checking re4uires an ob@ect to bede%ined and set u& so as not to &erforma!tve !#e!$s

defne #ost

9

Use %ener!-#ost

#ost5name ln+ox

Address

active_checks_enable !

&assve5!#e!$s5ena+led

;

Con%iguring ser!ices is exactl$ thesame as 6ith hosts

defne serv!e

9

Use &n%-tem&late #ost5name ln+ox

serv!e5des!r&ton )ING

acti!e)checks)enabled :

&assve5!#e!$s5ena+led

;

In t#s !ase3 Na%os ll never &erform an/ a!tve !#e!$s on ts on and ll onl/rel/ on t#e results t#at are &assed to t

7e !an also !onf%ure Na%os so t#at f no ne nformaton #as +een &rovdedt#n a !ertan &erod of tme3 t ll use a!tve !#e!$s to %et t#e !urrent status oft#e #ost or serv!e b$ setting the acti!e)checks)enabled option to ;


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NSCA

NSCA s an a&&l!aton t#at allos t#e sendn% of results dre!tl/ to t#eNa%osexternal !ommand &&e

NSCA !onssts of to &artst#e server and t#e !lent

'#e &art res&ons+le for re!evn% !#e!$ results and &assn% t#em to Na%os s t#e

server '#s lstens on a s&e!f! 'C) &ort for NSCA !lents &assn% nformaton

It a!!e&ts and aut#ent!ates n!omn% !onne!tons and &asses t#ese results to t#eNa%os external !ommand &&e

All nformaton s en!r/&ted usn% t#e MCr/&t l+rar/


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NSCA


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NSCA


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NSCA


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NSCA

NSCA s an a&&l!aton t#at allos t#e sendn% of results dre!tl/ to t#eNa%osexternal !ommand &&e

NSCA !onssts of to &artst#e server and t#e !lent

'#e &art res&ons+le for re!evn% !#e!$ results and &assn% t#em to Na%os s t#e

server '#s lstens on a s&e!f! 'C) &ort for NSCA !lents &assn% nformaton

It a!!e&ts and aut#ent!ates n!omn% !onne!tons and &asses t#ese results to t#eNa%os external !ommand &&e

All nformaton s en!r/&ted usn% t#e MCr/&t l+rar/


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Clustern%

One of t#e frst +ottlene!$s or%anatons ll run nto s &erforman!e #enmontorn% a lar%e num+er of #osts and serv!es

'#s !an o!!ur even earler f /ou are usn% &erforman!e #andlers on /our serv!eor #ost !#e!$s

One a/ to resolve &erforman!e &ro+lems s to !luster Na%os

!lustern% s also ver/ useful #en t#ere are a num+er of remote stes t#at need to+e montored +/ Na%os

Usuall/3 t#ere are one or more Na%os nstan!es t#at re&ort nformaton to a sn%le!entral Na%os nstan!e

'#e servers t#at re&orts nformaton to anot#er Na%os ma!#ne as a slave

A Na%os nstan!e t#at re!eves re&orts from oneor more slaves ll +e referred toas a master


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One Na%os Instan!e


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Clustern%

One of t#e frst +ottlene!$s or%anatons ll run nto s &erforman!e #enmontorn% a lar%e num+er of #osts and serv!es

'#s !an o!!ur even earler f /ou are usn% &erforman!e #andlers on /our serv!eor #ost !#e!$s

One a/ to resolve &erforman!e &ro+lems s to !luster Na%os

!lustern% s also ver/ useful #en t#ere are a num+er of remote stes t#at need to+e montored +/ Na%os

Usuall/3 t#ere are one or more Na%os nstan!es t#at re&ort nformaton to a sn%le!entral Na%os nstan!e

'#e servers t#at re&orts nformaton to anot#er Na%os ma!#ne as a slave

A Na%os nstan!e t#at re!eves re&orts from oneor more slaves ll +e referred toas a master


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Man/ Na%os Instan!es


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Clustern%


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Clustern%

Data "lo


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Clustern%


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Clustern% remote site Con%iguration

nstall Na%os as normal on t#e server and t#en !#an%e t#e follon% &arameters nna%os!f% to allo t to fun!ton &ro&erl/ n our Na%os !luster4

enable)noti%ications 1 : J 7e do not ant t#s nstan!e sendn% out

notf!atons

obsess)o!er)ser!ices1; J 7e ant t#e remote server to o+sess over

serv!es so all !#an%es ll +e re&orted +a!$ to t#e master server

oscp)command1nsca)send)result J '#s s a !ustom s!r&t s#on next

7t# t#ese !onf%uraton !#an%es n &la!e3 t#e remote Na%os server ll !all t#e!ommand ns!a5send5result after ever/ serv!e !#e!$ exe!uted on t#e remote#ost

'#e ns!a5send5result s!r&t ll t#en forard t#e serv!e !#e!$ results to t#emaster Na%os server

l


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Clustern% '#e ns!a5send5result s!r&t ll t#en forard t#e serv!e !#e!$ results to t#e

master Na%os server )la!e t#e follon% defnton for ns!a5send5result n /our

!ommands

!onf%uraton fle 0!ommands!f% +/ default14

de%ine command

command)name nsca)send)result

command)line /usr/local/nagios/libexec/nsca)send)result",+#N02E +E-=ICEDE+C< +E-=ICE+#0#E+E-=ICE,U#5U#

Documents

Nagios Module 2