AdminSysGNULinux

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{{tag>Nagios}}

# Exemple simple de conf Nagios

Voir :
* https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/3/en/objectinheritance.html
* https://packages.debian.org/sid/nagios4-common
* https://github.com/Webconverger/nagios

Voir aussi :
* https://github.com/monitoring-fr/Documentation-Nagios-3.x-French


## Arborescence proposée


Le fichier de conf principale appelant tous les autres :
* etc/nagios.cfg 
  * Voir https://github.com/NagiosEnterprises/nagioscore/blob/master/t/etc/nagios.cfg

Fichier contenant les commandes à exécuter :
* etc/objects/commands.cfg

Ce fichier ne doit pas contenir de mot de passe. 

Le fichier contenant les mots de passe utilisés par commands.cfg :
* etc/resource.cfg

Ce fichier ne devrait être en lecture que pour l'utilisateur "nagios"


Fichiers de conf basiques modifiés peu souvent :
* etc/objects/templates.cfg
* etc/objects/timeperiods.cfg
* etc/objects/contacts.cfg
* etc/objects/localhost.cfg



Fichier de conf contenant la liste des hôtes à superviser :
* etc/objects/servers.cfg

Il est possible d'avoir plusieurs fichiers de ce genre. Exemple : switch.cfg, printer.cfg, windows.cfg...

Le nom des fichiers cfg est libre, mais ils doivent être appelés par nagios.cfg


## Exemple de conf

### Fichier de conf principale nagios.cfg

Extrait

`nagios.cfg`
~~~bash
#cfg_file=/usr/local/nagios/etc/objects/commands.cfg
#cfg_file=/usr/local/nagios/etc/objects/contacts.cfg
#cfg_file=/usr/local/nagios/etc/objects/timeperiods.cfg
#cfg_file=/usr/local/nagios/etc/objects/templates.cfg
#cfg_file=/usr/local/nagios/etc/objects/localhost.cfg
#cfg_file=/usr/local/nagios/etc/objects/servers.cfg
#cfg_file=/usr/local/nagios/etc/objects/windows.cfg
#cfg_file=/usr/local/nagios/etc/objects/switch.cfg

cfg_dir=/usr/local/nagios/etc/objects/
resource_file=/usr/local/nagios/etc/resource.cfg

nagios_user=nagios
nagios_group=nagios

check_external_commands=1
max_concurrent_checks=0
retain_state_information=0
enable_flap_detection=1

date_format=iso8601

use_syslog=1
log_file=/usr/local/nagios/var/nagios.log
debug_level=0
debug_file=/usr/local/nagios/var/nagios.debug
~~~



### Fichier commands.cfg

`commands.cfg`

~~~c
# 'check-host-alive' command definition
define command {
    command_name    check-host-alive
    command_line    $USER1$/check_ping -H $HOSTADDRESS$ -w 3000.0,80% -c 5000.0,100% -p 5
}

# 'notify-service-by-email' command definition
define command {
    command_name    notify-service-by-email
    command_line    /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$SERVICEOUTPUT$" | /bin/mail -s "** $NOTIFICATIONTYPE$ Service Alert: $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **" $CONTACTEMAIL$
}

# 'notify-host-by-email' command definition
define command {
    command_name    notify-host-by-email
    command_line    /usr/bin/printf "%b" "***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $HOSTOUTPUT$\n\nDate/Time: $LONGDATETIME$\n" | /bin/mail -s "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is $HOSTSTATE$ **" $CONTACTEMAIL$
}


# NOTE:  The following 'check_local_...' functions are designed to monitor
#        various metrics on the host that Nagios is running on (i.e. this one).
define command {
    command_name    check_local_users
    command_line    $USER1$/check_users -w $ARG1$ -c $ARG2$
}

define command {
    command_name    check_centreon_snmp_linux_mem
    command_line    $USER1$/centreon_plugins --plugin=os::linux::snmp::plugin --hostname=$HOSTADDRESS$ --snmp-version=3 --snmp-username $USER6$ --authprotocol MD5 --authpassphrase "$USER7$" --mode=memory --warning-usage-prct $ARG1$ --critical-usage-prct $ARG2$
}

#define command {
#    command_name    check_active_router
#    command_line    $USER1$/check_snmp_active_router.sh -v 3 -a MD5 -A "$USER4$" -l authNoPriv -u $USER3$
#}

#define command {
#    command_name    trigger_memory
#    command_line    /usr/bin/tclsh $USER1$/eventhandlers/app_snmp_pxy.tcl MEM $HOSTNAME$ $SERVICEDESC$ #$SERVICESTATE$
#}
~~~

Ce fichier contient les commandes qui seront exécutées.

Tous les scripts ne renvoyant que des données locales (de localhost), et donc ne contenant pas ''$HOSTADDRESS$'', devraient avoir en *command_name* le préfixe "check_local_"

Seul le fichier `localhost.cfg` devrait faire appel aux commandes "check_local_*"


### Fichier contenant les Templates

`templates.cfg`
~~~c
define contact {
    name                            generic-contact         ; The name of this contact template
    service_notification_period     24x7                    ; service notifications can be sent anytime
    host_notification_period        24x7                    ; host notifications can be sent anytime
    service_notification_options    w,u,c,r,f,s             ; send notifications for all service states, flapping events, and scheduled downtime events
    host_notification_options       d,u,r,f,s               ; send notifications for all host states, flapping events, and scheduled downtime events
    service_notification_commands   notify-service-by-email ; send service notifications via email
    host_notification_commands      notify-host-by-email    ; send host notifications via email
    register                        0                       ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL CONTACT, JUST A TEMPLATE!
}

# Generic host definition template - This is NOT a real host, just a template!
define host {
    name                            generic-host    ; The name of this host template
    notifications_enabled           1               ; Host notifications are enabled
    event_handler_enabled           1               ; Host event handler is enabled
    flap_detection_enabled          1               ; Flap detection is enabled
    failure_prediction_enabled      1               ; Failure prediction is enabled
    process_perf_data               1               ; Process performance data
    retain_status_information       1               ; Retain status information across program restarts
    retain_nonstatus_information    1               ; Retain non-status information across program restarts
    notification_period             24x7            ; Send host notifications at any time
    register                        0               ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!
}
 
define host {
    name                            linux-server     ; The name of this host template
    use                             generic-host     ; This template inherits other values from the generic-host template
    check_period                    24x7             ; By default, Linux hosts are checked round the clock
    check_interval                  5                ; Actively check the host every 5 minutes
    retry_interval                  1                ; Schedule host check retries at 1 minute intervals
    max_check_attempts              10               ; Check each Linux host 10 times (max)
    check_command                   check-host-alive ; Default command to check Linux hosts
    notification_period             workhours        ; Linux admins hate to be woken up, so we only notify during the day
                                                     ; Note that the notification_period variable is being overridden from
                                                     ; the value that is inherited from the generic-host template!
    notification_interval           120              ; Resend notifications every 2 hours
    notification_options            d,u,r            ; Only send notifications for specific host states
    contact_groups                  admins           ; Notifications get sent to the admins by default
    register                        0                ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!
}
 
# Custom
define host {
    name                            tpl-host-linux
    use                             linux-server
    hostgroups                      linux-hosts
    register                        0
}

 
define service {
    name                            generic-service  ; The 'name' of this service template
    active_checks_enabled           1                ; Active service checks are enabled
    passive_checks_enabled          1                ; Passive service checks are enabled/accepted
    parallelize_check               1                ; Active service checks should be parallelized (disabling this can lead to major performance problems)
    obsess_over_service             1                ; We should obsess over this service (if necessary)
    check_freshness                 0                ; Default is to NOT check service 'freshness'
    notifications_enabled           1                ; Service notifications are enabled
    event_handler_enabled           1                ; Service event handler is enabled
    flap_detection_enabled          1                ; Flap detection is enabled
    failure_prediction_enabled      1                ; Failure prediction is enabled
    process_perf_data               1                ; Process performance data
    retain_status_information       1                ; Retain status information across program restarts
    retain_nonstatus_information    1                ; Retain non-status information across program restarts
    is_volatile                     0                ; The service is not volatile
    check_period                    24x7             ; The service can be checked at any time of the day
    max_check_attempts              3                ; Re-check the service up to 3 times in order to determine its final (hard) state
    normal_check_interval           10               ; Check the service every 10 minutes under normal conditions
    retry_check_interval            2                ; Re-check the service every two minutes until a hard state can be determined
    contact_groups                  admins           ; Notifications get sent out to everyone in the 'admins' group
    notification_options            w,u,c,r          ; Send notifications about warning, unknown, critical, and recovery events
    notification_interval           60               ; Re-notify about service problems every hour
    notification_period             24x7             ; Notifications can be sent out at any time
    register                        0                ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL SERVICE, JUST A TEMPLATE!
}

# Local service definition template - This is NOT a real service, just a template!
define service {
    name                            local-service    ; The name of this service template
    use                             generic-service  ; Inherit default values from the generic-service definition
    max_check_attempts              4                ; Re-check the service up to 4 times in order to determine its final (hard) state
    normal_check_interval           5                ; Check the service every 5 minutes under normal conditions
    retry_check_interval            1                ; Re-check the service every minute until a hard state can be determined
    register                        0                ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL SERVICE, JUST A TEMPLATE!
}
 
# Custom
define service {
    name                            tpl-service-mca1
    max_check_attempts              1
    normal_check_interval           1
    retry_check_interval            1
    check_period                    24x7
    notification_interval           2000
    notification_period             24x7
    notification_options            w,c,r
    contact_groups                  admins
    register                        0
}

~~~

Ce fichier devrait être dédié aux Templates. Chaque bloque devrait contenir ''register 0''.

Pour utiliser un template il faut utiliser la directive "use". Nous verons des exemples dans la suite.

Pour tous les nouveaux objets templates, nous recommandons pour une meilleurs lisibilité de leurs appliquer une convention de nommage spécifique. 
Par exemple en les préfixant par "tpl-"


### Passons rapidement sur timeperiods.cfg & contacts.cfg

`timeperiods.cfg`
~~~c
# This defines a timeperiod where all times are valid for checks, 
# notifications, etc.  The classic "24x7" support nightmare. :-)
define timeperiod {
    timeperiod_name  24x7
    alias            24 Hours A Day, 7 Days A Week
    sunday           00:00-24:00
    monday           00:00-24:00
    tuesday          00:00-24:00
    wednesday        00:00-24:00
    thursday         00:00-24:00
    friday           00:00-24:00
    saturday         00:00-24:00
}

# 'workhours' timeperiod definition
define timeperiod {
    timeperiod_name  workhours
    alias            Normal Work Hours
    monday           09:00-17:00
    tuesday          09:00-17:00
    wednesday        09:00-17:00
    thursday         09:00-17:00
    friday           09:00-17:00
}
~~~

`contacts.cfg`
~~~c
define contact {
    contact_name            nagiosadmin       ; Short name of user
    use                     generic-contact   ; Inherit default values from generic-contact template (defined above)
    alias                   Nagios Admin      ; Full name of user
    email                   nagios@localhost  ; <<***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
}


define contactgroup {
    contactgroup_name       admins
    alias                   Nagios Administrators
    members                 nagiosadmin
}
~~~

Notez ici la directive "use" parmetant d"hétirer du template.




### Fichier localhost.cfg

`localhost.cfg`
~~~c
define host {
    use                     linux-server   ; Name of host template to use
                                           ; This host definition will inherit all variables that are defined
                                           ; in (or inherited by) the linux-server host template definition.
    host_name               localhost
    alias                   localhost
    address                 127.0.0.1
}


define hostgroup {
    hostgroup_name          linux-servers  ; The name of the hostgroup
    alias                   Linux Servers  ; Long name of the group
    members                 localhost      ; Comma separated list of hosts that belong to this group
}


define service {
    use                     local-service           ; Name of service template to use
    host_name               localhost
    service_description     Current Users
    check_command           check_local_users!20!50
}

~~~

Toutes les commandes présentent dans ce fichier devraient avoir pour check_command "check_local_". 
Voir `commands.cfg`


### Fichier servers.cfg

`servers.cfg`
~~~c
define host {
    host_name               srv01
    use                     tpl-host-linux
    alias                   srv01
}

define host {
    host_name               srv02
    use                     tpl-host-linux
    alias                   srv01
}


define hostgroup {
    hostgroup_name          linux-hosts
    alias                   Linux Servers
}

define hostgroup {
    hostgroup_name          RED
    alias                   RedondanceEnvLogique
    members                 srv01
}

define hostgroup {
    hostgroup_name          App
    alias                   ReseauGlobalApp
    # hostgroup_members      linux-hosts, Switchs, Routeurs, printer-hosts
    hostgroup_members       linux-hosts
}


define service {
    service_description     Memory
    use                     tpl-service-mca1
    hostgroup_name          linux-hosts
    check_command           check_centreon_snmp_linux_mem!80!90
    # event_handler           trigger_memory
}
~~~


Notez que un hostgroup peut inclure des hôtes avec `members`

ou d'autres hostgroups avec `hostgroup_members`

Souvent on préférera utliser les templates à l'aide de la directive "use". Voir notre exemple avec `tpl-host-linux`


## Vérification de la conf

### Vérif

~~~bash
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
~~~

### Commandes

Trouver les commandes non utilisées
~~~bash
for CMD in $(grep command_name etc/objects/commands.cfg | grep -v "^#" |awk '{ print $2}' | sort  -u) ; do grep -q "$CMD" $(find etc/objects/ -type f -not -name commands.cfg) || echo $CMD; done
~~~

Trouver les commandes en double
~~~bash
diff <(grep -v ^# etc/objects/commands.cfg | awk '/command_name/ { print $NF }' | sort) <(grep -v ^# etc/objects/commands.cfg | awk '/command_name/ { print $NF }' | sort -u)
~~~


#### Sondes locales


Toutes les sondes locales (qui remonte des infos du host sur lequel le script est exécuté) devraient avoir un ''command_name'' commençant par "check_local_"

Sauf exception seules les fichiers suivants devraient contenir ce motif
~~~
$ rgrep -l check_local_ *
objects/commands.cfg
objects/localhost.cfg
~~~




Même chose avec les ''local-service''

~~~
$ rgrep -l local-service *
objects/templates.cfg
objects/localhost.cfg
~~~


### templates.cfg

* Tous les bloques de code ''register 0'' devraient être dans le fichier templates.cfg
* Tous les bloques de code présent dans le fichier templates.cfg devrait avoir ''register 0''


### Autres conditions

* Pour toute directive "use" il doit y avoir un template corespondant (template.cfg)
* Pour chaque "check_command" il doit y avoir une entrée "command_name" correspondante (commands.cfg)
* Tous les noms indiqués par la directive "name" dans les objets de type "host" doivent être résolvables