hostgroup_members

Custom macros in host definitions

August 16, 2008August 8, 2014 Christian Leave a comment

Well, I was playing with the hostgroup inheritance earlier. One problem with that is, if you define a duplicate service Nagios is really unpredictable or rather inconsistent. Now, as Thomas Guyot-Sionnest told me, I should try custom macros for the check definition. So what I did was the following:

templates/host-windows.cfg

define host {
  name         generic-windows
  register     0
  _RDPPORT     3389
}

define host {

name generic-windows

_RDPPORT 3389

}

hostgroups/windows.cfg

define hostgroup {
  hostgroup_name          windows
  alias                   Windows Servers
  hostgroup_members       windows-terminal
}

define service {
  use                     generic-service
  check_command           check_tcp!$_HOSTRDPPORT$
  service_description     RDP
  hostgroup_name          windows
}

define hostgroup {

hostgroup_name windows

alias Windows Servers

hostgroup_members windows-terminal

}

define service {

use generic-service

check_command check_tcp!$_HOSTRDPPORT$

service_description RDP

hostgroup_name windows

}

hosts/terminal1.cfg

define host {
  use                   generic-windows
  host_name             terminal1
  alias                 terminal1.barfoo.org
  address               10.0.0.250
  parents               barfoo-home
  hostgroups            windows-terminal
  _RDPPORT              3390
}

define host {

use generic-windows

host_name terminal1

alias terminal1.barfoo.org

address 10.0.0.250

parents barfoo-home

hostgroups windows-terminal

_RDPPORT 3390

}

As you can see, the default RDP port is 3389 (as defined in the host template), but for some systems you might want to “change” the port (for example, if you’re having a Citrix farm and you changed the RDP port to something else and still want to be able to check whether or not the RDP service is active), thus the check using the macro, and a single host redefining the macro, thus having a bit more flexibility.

Nagios 3 and hostgroup inheritance

August 8, 2008August 8, 2014 Christian Leave a comment

As I wrote some time ago, I was trying to utilize Nagios 3.x’s neat feature of “nested” hostgroups. Well, as it turned out I thought it worked differently; basically like this:

define hostgroup {
        hostgroup_name      a-parent-hostgroup
        alias               Our toplevel parent hostgroup
}

define service {
       use                  generic-service
       check_command        check_dummy!0!
       service_description  SSH
       hostgroup_name       a-parent-hostgroup
}

define hostgroup {
        hostgroup_name      a-child-hostgroup
        hostgroup_members   a-parent-hostgroup
        alias               Our child hostgroup
}

define service {
       use                  generic-service
       check_command        check_dummy!0!
       service_description  LOAD
       hostgroup_name       a-child-hostgroup
}

define hostgroup {

hostgroup_name a-parent-hostgroup

alias Our toplevel parent hostgroup

}

define service {

use generic-service

check_command check_dummy!0!

service_description SSH

hostgroup_name a-parent-hostgroup

}

define hostgroup {

hostgroup_name a-child-hostgroup

hostgroup_members a-parent-hostgroup

alias Our child hostgroup

}

define service {

use generic-service

check_command check_dummy!0!

service_description LOAD

hostgroup_name a-child-hostgroup

}

As you can cleary see on line 14, I thought you define the relation between two hostgroups in the child hostgroup. The problem with it was basically (as I said in the earlier posts), that all the services defined for the child hostgroups are handed on upwards to the parent hostgroup(s).

But after talking to Tobi, I quickly found out, that the relation is in fact defined within the parent hostgroup. So if you simply put hostgroup_members within the parent hostgroup and define all child hostgroups which should inherit from the parent one, you should be just fine.

Nagios Hostgroup Inheritance (continued)

July 19, 2008August 16, 2014 Christian Leave a comment

Well, it turns out that my thought was ultimativly flawed. When defining the hostgroup_members in the lower tiers, nagios is association the checks from the lower tier with the upper tiers. Thus propagandating all checks upwards, and me ending up with ~250 checks instead of ~150.

Gonna have to try to define the dependency backwards, maybe that’ll help. But that’s a topic for Monday. Guess I’ll finish viewing Ghost in the Shell – Stand Alone Complex first.

Nagios Hostgroup Inheritance

July 17, 2008August 16, 2014 Christian 3 Comments

As I wrote earlier, I recently virtualized our nagios. Along with that came a complete “redesign” of how checks are applied. Up till now, I defined checks for each and every single server, thus ending up with ~25 files, each holding roughly 6 checks which are in the same file just sorted by hostname.

As you can imagine, it gets quite confusing with that amount of checks (~150). So the last two days I spent on reorganizing (with Visio), on which object/hostgroup placing a check would make sense. Now, this is my first result of two days planning, reorganizing, reordering and moving hosts into different hostgroups.

Nagios Hostgroup Inheritance - Linux — Nagios Hostgroup Inheritance – Linux

Nagios Hostgroup Inheritance - Windows — Nagios Hostgroup Inheritance – Windows

Thanks to Josh (and Chris I think), realizing the above is gonna get quite easy. Gonna talk about the config layout itself about once I have it all wrapped up. Stay tuned!

S	M	T	W	T	F	S
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30	31