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Explication

Le module SLA permet de calculer les valeurs de SLA (Service Level Agreement) des éléments supervisés et les stocker dans la base de données Mongodb définie dans le fichier de configuration ci dessous. Il est également possible, via ce fichier, de modifier la méthode de calcul des SLA (par exemple, choisir de considérer un Warning comme une période positive de SLA, ou encore d'exclure les périodes de maintenance dans le calcul).

Configuration

Voici le fichier CFG de configuration présent dans : /etc/shinken/modules/sla.cfg

Code Block
languagebash
#===============================================================================
# sla
#===============================================================================
# Daemons that can load this module:
# - broker (to save sla information into a mongodb database)
# Modules that can load this module:
# - WebUI (to display sla data to the users)
# This module compute and save SLA values into a mongodb database
#===============================================================================


define module {

# Shinken Enterprise. Lines added by import core. Do not remove it, it's used by Shinken Enterprise to update your objects if you re-import them.
    _SE_UUID             core-module-d05cd3505adb11e5884b080027f08538
    _SE_UUID_HASH        05d3d1d1cce1f5e03b43936aad25e68f
# End of Shinken Enterprise part

    #======== Module identity =========
    # Module name. Must be unique
    module_name          sla

    # Module type (to load module code). Do not edit.
    module_type          sla

    #======== Database connection =========
    # mongodb uri definition for connecting to the mongodb database. You can find the mongodb uri
    # syntax at https://docs.mongodb.com/manual/reference/connection-string/
    uri                  mongodb://localhost/?w=1&fsync=false

    # If you want to securize your mongodb connection you can enable the ssh use_ssh_tunnel that will
    # allow all mongodb to be encrypted & authentificated with SSH
    # Should use a SSH tunnel (Default 0=False)
    # use_ssh_tunnel          0

    # If the SSH connection goes wrong, then retry use_ssh_retry_failure time before_shinken_inactive
    # Default: 1
    # use_ssh_retry_failure   1

    # SSH user/keyfile in order to connect to the mongodb server.
    # Default: shinken
    # ssh_user                shinken

    # Default: ~shinken/.ssh/id_rsa
    # ssh_keyfile             ~shinken/.ssh/id_rsa

    # Timeout in order to establish a connection, in seconds
    # Default: 10
    # mongo_timeout  10

    # Which database is used to store sla data
    database             shinken

    #======== Module options =========
    # Raw SLA can be kept during X days. In case of issue, these data will be used to re-perform SLA computation.
    # The drawback of this feature is that it takes more disk space.
    #keep_raw_sla_day   7            ;optional, defaults to 7

    # Duration in day to keep SLA info,
    # Default value is -1. It mean SLA are keep forever, in this case to mongo database will grow endlessly.
    # Minimal value is 7 day
    #nb_stored_days   -1

    # SLA are computed on a daily basis. SLA of the current day are always recomputed after a configuration change. SLA from days before are by default not recomputed.
    # If 1, old SLA will be recomputed with current settings.
    # If 0, old SLA will not be recalculated [default]
    # recompute_old_sla      0

    #======== SLA calculation ========
    # Some status can impact positively (counted as OK/UP), negatively (counted as CRITICAL/DOWN) or not impact the SLA
    # (is not counted, meaning the period of study is reduced by the period that is not counted).
    # This configuration aims at giving Shinken administrators a way to configure how the SLA are calculated.

    # If 1, Warning counts as UP
    # If 0, Warning counts as DOWN [default]
    # warning_counts_as_ok   0

    #  == Unknown periods ==
    #    - include:  Only status is considered. "Unknown" status is counted negatively in the SLA. [default]
    #    - exclude:  Unknown are not counted from SLA considered period
    #    - ok:       Unknown are considered as UP periods
    # unknown_period        include

    #  == No_data periods ("Missing data" and "Shinken inactive" status) ==
    #    - include:  Only status is considered. "Missing data" and "Shinken inactive" status are counted negatively in the SLA. [default]
    #    - exclude:  No_data are not counted from SLA considered period
    #    - ok:       No_data are considered as UP periods
    # no_data_period        include

    #  == Downtime periods ==
    #    - include:  Only status is considered. [default]
    #    - exclude:  Downtimes are not counted from SLA considered period
    #    - ok:       Downtimes are considered as UP periods
    #    - critical: Downtimes are considered as DOWN periods
    # downtime_period    include

    #======== INTERNAL options =========
    #INTERNAL : DO NOT EDIT FOLLOWING PARAMETRE WITHOUT YOUR DEDICATED SUPPORT
    # == time of inactivation of the broker before considering that shinken is inactive (in sec) ==
    #time_before_shinken_inactive  30
    # == maximum number of elements archived in one bulk pass ==
    #size_chunk_to_archive         10 000
    # == time between two chunk to archive ==
    #time_between_two_chunks       0.1
    # == default value of the interval check (in minutes) ==
    #default_check_interval            5
    # == delay before the creation of missing data period (in check intervale) ==
    #margin_create_new_range       1.5
    # == max delay before creating missing data period (in minutes) ==
    #margin_create_new_range_max   10

    # Explanatory example of the property margin_create_new_range
    # For an element with a check interval at 1min and margin_create_new_range at 1.5 which equals 1min30s of time delay.
    # If the interval check is at 1h the delay would be at 1h30 but the delay is limited by margin_create_new_range_max which limits the delay to 10min.
    #
    # An OK status is given by the scheduler at 12h30
    # A new OK status is given by the scheduler at 12h40
    # The scheduler should have given a new status at 12h31 but it gave it at 12h40 which is 9min of time delay.
    # So that 9min > 1min30s a missing data period is created.

}



Configurer l'accès à la base MongoDB

Cette configuration s'effectue dans le fichier de configuration du module SLA.



Code Block
languagebash
define module{


...


...


...

   

    #======== Database connection =========

    # mongodb uri definition for connecting to the mongodb database. You can find the mongodb uri
    # syntax at

    # mongodb uri definition for connecting to the mongodb database. You can find the mongodb uri
    # syntax at https://docs.mongodb.com/manual/reference/connection-string/

    uri                  mongodb

    uri                  mongodb://localhost/?w=1&fsync=false

    # If you want to securize your mongodb connection you can enable the ssh


    # If you want to securize your mongodb connection you can enable the ssh use_ssh_tunnel that
will
    # allow all mongodb to be encrypted & authentificated with SSH
    # Should use a SSH tunnel (Default 0=False)
    # use_ssh_tunnel          0
    # If the SSH connection goes wrong, then retry
 will
    # allow all mongodb to be encrypted & authentificated with SSH
    # Should use a SSH tunnel (Default 0=False)
    # use_ssh_tunnel          0

    # If the SSH connection goes wrong, then retry use_ssh_retry_failure time before_shinken_inactive

    #

    # Default:
1
    #
 1
    # use_ssh_retry_
failure   1
    # SSH
failure   1

    # SSH user/keyfile in order to connect to the mongodb server.

    #

    # Default:
shinken
    # ssh_user                shinken
    # Default:
 shinken
    # ssh_user                shinken

    # Default: ~shinken/.ssh/id_rsa

    # ssh_keyfile            

    # ssh_keyfile             ~shinken/.ssh/id_rsa

    # Timeout in order to establish a connection, in seconds
    # Default: 10
    # mongo_timeout  10
    # Which database is used to store sla data
    database             shinken
...
...
...


    # Timeout in order to establish a connection, in seconds
    # Default: 10
    # mongo_timeout  10

    # Which database is used to store sla data
    database             shinken


...
...
...
}


Les données SLA sont stockées dans la base Mongo locale au Broker

Pour se connecter au serveur Mongo utilisé pour le stockage des données SLA, 2 méthodes sont disponibles:

  • Connexion directe: Par défaut, mais non sécurisée.
  • Tunnel SSH: Shinken se connecte au serveur Mongo au travers d'un module SSH pour plus de sécurité





Connexion directe au serveur Mongo

Par défaut, le module SLA se connecte de manière directe au serveur Mongo pour y lire et écrire les données SLA.

Dans la configuration du module SLA, on sait que la connexion se fait de manière directe lorsque le paramètre "use_ssh_tunnel" est à 0.
/etc/shinken/modules/retention-mongodb.cfg

define module {                                                                                        
                                                                                                                                                                                                                
    #======== Module identity =========                                                                
    # Module name. Must be unique                                                                      
    module_name     sla                                                                   
    ...                                                   
    use_ssh_tunnel  0
    ...                                                                                                                                                                                      
}

Cette méthode de connexion a pour avantage d'être facile à configurer au niveau de Shinken. Par contre, elle oblige à permettre l'accès à la base Mongo au monde extérieur, et donc s'exposer à des problèmes de sécurité.

La sécurisation de la base Mongo est bien sur toujours possible (voir Sécurisation des connexions aux bases MongoDB) mais bien plus complexe à mettre en place. La méthode de connexion par SSH est donc préférable pour des raisons pratiques et de sécurité.

 (par défaut ~/.ssh/id_rsa)

Connexion par SSH au serveur Mongo

Le module SLA peut également se connecter par tunnel SSH au serveur Mongo, pour des raisons de sécurité.


  • Dans la configuration du serveur Mongo (/etc/mongod.conf), assurez-vous que le paramètre "bind_ip" est positionné pour n'écouter que sur l'interface locale:

bind_ip=127.0.0.1

  • Depuis le serveur hébergeant le Broker, assurez-vous que les clés publiques SSH de l'utilisateur lançant le daemon (par défaut "shinken") sont autorisées sur le serveur hébergeant Mongo :
    • Connectez-vous avec le user lançant le démon sur le serveur Shinken
    • Générez la paire de clés SSH si nécessaire
    • Copiez la clé publique sur le serveur mongo

root@serveur_shinken # su - shinken
shinken@serveur_shinken $ ssh-keygen
shinken@serveur_shinken $ ssh-copy-id user_distant@serveur_mongo
[...]
shinken@serveur_shinken $ ssh user_distant@serveur_mongo
user_distant@serveur_mongo $


Si vous avez un serveur qui héberge à la fois le démon Broker et la base MongoDB (cas d'une installation standard), il vous faudra également appliquer ces commandes pour autoriser l'utilisateur shinken à se connecter automatiquement sur lui même en SSH


Modifiez la configuration du module SLA

  • le paramètre "use_ssh_tunnel" doit être positionné à 1
  • le paramètre "use_ssh_retry_failure" permet de spécifier le nombre supplémentaire de tentatives lors de l'établissement du tunnel SSH si ce dernier n'arrive pas à être établi.
  • le paramètre "ssh_user" doit être positionné au user utilisé pour se connecter au serveur mongo (user_distant dans l'exemple précédent)
  • le paramètre "ssh_keyfile" doit pointer vers la clé ssh privée sur le serveur Shinken