Changes between Version 2 and Version 3 of Doc/Monitoring/Nagios

Timestamp:

Jun 9, 2008, 8:13:43 PM (17 years ago)

Author:

/DC=es/DC=irisgrid/O=uam/CN=luisf-munnoz

Comment:

Nagios server documentation, pending lists of packages.

Doc/Monitoring/Nagios

@@ -4 +4 @@
 [[TOC(inline)]]
 
-Nagios configuration requires both a set of client templates for commands to be run on clients by the Nagios Remote Plug-in Executor (NRPE) and a set of server templates configuring contacts for alarms, hosts to be monitored services and so on.
+Nagios configuration requires both a set of client templates for commands to be run on clients by the Nagios Remote Plug-in Executor (NRPE) and a set of server templates configuring contacts for alarms, hosts to be monitored, services (AKA sensors) and so on.
 
 = Configuring the Nagios server =
+
+The configuration of a Nagios server is done in a set of ''standard'' templates, on the ''monitoring/nagios'' namespace.
+
+Also, sensors are provided for many of the plug-ins described in [http://www.gridpp.ac.uk/wiki/Nagios_Plugins GridPP's wiki]
+
+== What is monitored ==
+
+In principle, all hosts present on `DB_MACHINE` are expected to be monitored and are added to Nagios configuration. This is done with the variables `HOSTSLIST`, which is automatically derived from `DB_MACHINE`. Additional hosts can be specified with the variable `NAGIOS_EXTRA_HOSTS`.
+
+Currently, all hosts are considered to have the same settings. Finer-grained settings (for instance, separate hosts to be monitored on working and non-working hours) are yet to be done.
+
+== Hardware-related monitoring ==
+
+The variable `HW_LISTINGS` is somewhat the "inverse" from `DB_MACHINE`: it is a structure with fields related to some hardware attribute and whose values are the lists of nodes with such attribute. For instance, `HW_LISTINGS["per_cpu"]["_4"]` is the list of nodes with 4 CPU cores, should that be 4 old Pentium or a single Barcelona chip. See [#Variable-index here] for the full description of each variable.
+
+== Specifying commands ==
+
+A structure template with all the commands used at UAM is provided, as an example. Variable `NAGIOS_COMMANDS_TEMPLATE` is the name of a structure template with all the command definitions you need. You can write your own commands template, and even include the example one. A command template is just a set of `"command_name" = "command_definition"` lines, like this:
+{{{
+"check_ftp" = "$USER1$/check_ftp -H $HOSTADDRESS$";
+"notify-by-email" = "/bin/echo '$SERVICEOUTPUT$' | /bin/mail -s '$SERVICESTATE$ alert for $HOSTALIAS$($HOSTNAME$)/$SERVICEDESC$' $CONTACTEMAIL$";
+"check_nrpe_ncd" = "$USER1$/check_nrpe -H $HOSTADDRESS$ -c check_ncd";
+}}}
+
+== Host aliases and host-specific customization ==
+
+Additional, per-host customization is possible with another template, called `NAGIOS_HOSTALIASES_TEMPLATE`. It is a full template, not an structure one. It is a rather poor way of specifyng customizations, better ideas are welcomed.
+
+== Host groups ==
+
+A structure template for defining host groups can be supplied with the `NAGIOS_HOSTGROUPS_TEMPLATE` variable.
+
+== Macros ==
+
+User macros can be supplied with the `NAGIOS_MACROS_TEMPLATE`. By default, `$USER1$` and `$USER2$` are set with sensible values. The macros file will be written with 0600 permissions, so it is safe to place passwords here, if needed.
+
+== Time periods ==
+
+A structure template can be supplied with the `NAGIOS_TIMEPERIODS_TEMPLATE`. The default templates provide only a '''always''' timeperiod.
+
+== Contacts and contact groups ==
+
+Contacts and contact groups for alarms can be specified with structure templates called `NAGIOS_CONTACTS_TEMPLATE` and `NAGIOS_CONTACTGROUPS_TEMPLATE`. I provided an example template under '''monitoring/nagios/contacts''', but please adapt it to your needs!!
+
+== Services ==
+
+Each service must be provided via a structure template. This way, the `use` directive can be imitated with just an include. So, the variable `NAGIOS_SERVICE_TEMPLATES` is a list with the names of the templates that fully describe services.
+
+For instance,
+{{{
+include monitoring/nagios/services/fast-service;
+
+'service_description'='DNS response time';
+'check_command'= list (
+'check_dns',
+    'www.cern.ch',
+    '2',
+    '5');
+}}}
+
+=== Generic services ===
+
+As seen in the previous example, you can reduce the amount of code by including some other structure template and changing the appropriate values. For this, 6 generic templates are provided:
+
+ `generic-service`::
+   A "generic" service, with the appropriate contact groups, and other usual settings. Before sending an alarm, the check is tried 4 times. Alarms are re-sent each 4 hours.
+ `fast-service`::
+   A `generic-service` to be checked each 5 minutes, or each minute in case of problems.
+ `performance-service`::
+   A `fast-service` to be checked each 30 minutes, or each 5 minutes in case of problems.
+ `security-service`::
+   A ''volatile'' `fast-service` to be checked each 20 minutes.
+ `slow-service`::
+   A `fast-service` to be checked each hour, or each 20 minutes in case of problems. Alarms are re-sent each 7 hours.
+ `expire-service`::
+   A `fast-service` to be checked each 48 hours. Alarms are re-sent each 50 hours. It is useful for checking certificate expirations.
+
+=== Checking for a host load ===
+
+The acceptable load on a host depends on the number of CPUs and cores on it. For instance, having a single-core node on load 4 is problematic, whereas an 8-core node is wasting CPU with that same load.
+
+The function `generate-check-load-services` is aimed at this. It generates service structures based on the ''monitoring/nagios/services/load'' templates, for all hosts in `DB_MACHINE`, setting sensible limits. These are:
+|| ||'''Load 1'''||'''Load 5'''||'''Load 15'''||
+||'''Warning'''||cores*2||cores*1.75||cores*1.5||
+||'''Critical'''||cores*3||cores*2||cores*1.75
+
+The limits are hardcoded in the function, a more flexible approach will be provided (some day).
+== External configuration files ==
+
+If you have existing configuration files, or if parts of your configuration are generated by tools other than ncm-nagios, you can integrate them with the `NAGIOS_EXTERNAL_FILES` variable.
+
+== General options ==
+
+The component provides sensible defaults for most of the Nagios options. If you want to override any of these, set the variable `NAGIOS_GENERAL_OPTIONS`.
+
+== Variable index ==