A newbie configuration question

[Jim Avery]

On 30 December 2010 12:44, stan <stanb at panix.com> wrote:


> I am still confused by why the service def's have a filed for hostname. As
> you point out, services don't necisarily relate to hosts. They are
> functions provided, or statuses of a machine. and I would think thta
> servicegroups would be where the assoctation betwen the service, and
> thehosts that you want to check for that service wouldbe.
>
> Am I missing something?
>

Oh, I see.

No, I don't think you are missing anything.

I read somewhere (probably Wolfgang Barth's excellent book) that in
Nagios each service should be taken to be the combination of both the
service_description *and* the host_name.  Certainly in Nagios it is
not possible to have a service which exists without a host.  If you
look at the objects.cache file (probably under /usr/local/nagios/var/)
then you will see how Nagios stores each service definition.  Even if
you have defined services based on a hostgroup, Nagios will actually
internally regard each service on each host as a separate entity -
every service will have an entry for both host_name and
service_description.

The inbuilt service/host dependency and the host parent/child
relationships are important for Nagios in determining when it should
notify - in particular it won't notify for a service if the host is
down and usually won't notify for a host if the parent host is down.
The logic Nagios uses for determining dependencies and reachability
make Nagios a very powerful tool for ensuring you only receive
notifications for those hosts and services which are actually causing
the problem, not all the hosts and services which are down as a result
of the underlying problem.

I agree with you it can be a little counter-intuitive at times.  In
particular if you only have one service (for example ping) associated
with a host, it's not always obvious whether it would be appropriate
to acknowledge the service or the host when the ping fails.

------------------------------------------------------------------------------
Learn how Oracle Real Application Clusters (RAC) One Node allows customers
to consolidate database storage, standardize their database environment, and, 
should the need arise, upgrade to a full multi-node Oracle RAC database 
without downtime or disruption
http://p.sf.net/sfu/oracle-sfdevnl
_______________________________________________
Nagios-users mailing list
Nagios-users at lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nagios-users
::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. 
::: Messages without supporting info will risk being sent to /dev/null