Nagios Host Check Behaviour

[Daniel Tuecks]

Hello,

sounds like you want 'on demand host checks'.

"Regularly scheduled host checks are optional. If you set the
check_interval option in your host definition to zero (0), Nagios will
not perform checks of the hosts on a regular basis. It will, however,
still perform on-demand checks of the host as needed for other parts
of the monitoring logic.

On-demand checks are made when a service associated with the host
changes state because Nagios needs to know whether the host has also
changed state. Services that change state are often an indicator that
the host may have also changed state. For example, if Nagios detects
that the HTTP service associated with a host just changed from a
CRITICAL to an OK state, it may indicate that the host just recovered
from a reboot and is now back up and running. "

This is quoted from the official Nagios Documenation:
http://nagios.sourceforge.net/docs/3_0/hostchecks.html


Regards
Daniel

2011/6/23 Erik Sejr <eriks at ssimicro.com>:
> Hi,
> I have a question for the list regarding the behaviour of host checks in
> Nagios. My understanding was that host checks only took place if a
> service changed state, otherwise the state of the host was assumed based
> on the state of the services that host provides.
>
> We have a number of hosts, each with 1 or more passive services. Passive
> service checks arrive every five minutes with a freshness threshold set
> at 6 minutes. I am trying to get the behaviour described above - I only
> want nagios to perform a host check if a service changes state (from up
> to down). Otherwise, if all host services are OK I want nagios to assume
> the host the services are running on is also OK.
>
> I cannot seem to get it to do this, I can only get one extreme or the other:
>
> 1. Nagios checks the hosts, every 5 minutes regardless of the state of
> the services. I have confirmed this though a TCP dump on the server. The
> pings to the host go out (and come back) every 5 minutes.
>
> OR
>
> 2. Nagios never checks the hosts and they all show as PENDING for ever
> and ever.
>
> If The host template is configured as follows I get scenario #1
>
> define host{
> name                           remote-host
> hostgroups                     NBDC
> register                       0
> max_check_attempts             5
> notification_interval          5
> notification_period            24x7
> notification_options           d,r
> contact_groups                 regular_contacts
> check_command                  check-host-alive
> }
>
> If The host template is configured as follows I get scenario #2
>
> define host{
> name                           remote-host
> hostgroups                     NBDC
> register                       0
> max_check_attempts             5
> notification_interval          5
> notification_period            24x7
> notification_options           d,r
> contact_groups                 regular_contacts
> }
>
> The difference is the insertion or lack of the check_command.
>
> Hosts are defined to use the template in a basic manner:
>
> define host{
> host_name                       rtr01
> alias                           Router 01
> address                         rtr01.domain.com
> parents                         upstream-rtr01,upstream-rtr02
> use                             remote-host
> }
>
> define host{
> host_name                       dhcp1
> alias                           DHCP Network Gateway
> address                         dhcp1.domain.com
> parents                         rtr01
> use                             remote-host
> }
>
> Any thoughts? Am I missing something in the config?
>
> ------------------------------------------------------------------------------
> All the data continuously generated in your IT infrastructure contains a
> definitive record of customers, application performance, security
> threats, fraudulent activity and more. Splunk takes this data and makes
> sense of it. Business sense. IT sense. Common sense..
> http://p.sf.net/sfu/splunk-d2d-c1
> _______________________________________________
> 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
>

------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure contains a 
definitive record of customers, application performance, security 
threats, fraudulent activity and more. Splunk takes this data and makes 
sense of it. Business sense. IT sense. Common sense.. 
http://p.sf.net/sfu/splunk-d2d-c1
_______________________________________________
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