Service dependencies

william(at)elan.net william at elan.net
Fri Oct 20 04:41:43 CEST 2006


On Thu, 19 Oct 2006, Thomas Guyot-Sionnest wrote:

> I guess you mean setting it up in the service definition? But you'll have to
> define which host here as well. So is't excatly the same as the
> servicedependency  definition.
>
> Actually I'm just thinking there could be another way. What if by omiting
> one of the host_name / hostgroup_name variable, instead of failling check it
> would turn the "same host" mode.
>
> define servicedependency {
>  service_description           Master service
>  dependent_hostgroup_name      pool1,pool2
>  dependent_service_description Slave 1,Slave 2,Slave 3
>  same_host_dependency          1
>  notification_failure_criteria c,u
> }

Interestingly enough I made a patch (for 2.2 & 2.3) that does almost 
exactly that. But I did not do it cleanly as I did not add new option
and changed the behavior so that:

define servicedependency {
   hostgroup_name      		group1
   servicegroup_name		master_servicegroup
   dependent_servicegroup_name   slavegroup1,slavegroup2
   notification_failure_criteria c,u
   execution_failure_critieria	n
}

would add dependency for each host in hostgroup from services in master
group to all services in slave groups.

> There is no host_name defined for "Master service", so for each host in
> "dependent_hostgroup_name" it creates a dependency to "Master service" on
> the same host.
>
> Does it makes sense?
>
> Thomas
>
>> -----Original Message-----
>> From: nagios-devel-bounces at lists.sourceforge.net
>> [mailto:nagios-devel-bounces at lists.sourceforge.net] On Behalf
>> Of Tobias Mucke
>> Sent: October 19, 2006 11:31
>> To: Nagios-Devel
>> Subject: Re: [Nagios-devel] Service dependencies
>>
>> Hi,
>>
>> since we are using Nagios in a large environment here, we
>> also have to fight with service dependencies and the approach
>> how to configure it. What I would like to see in Nagios is
>> the possibility to define that a service always depends on
>> another service without even mentioning a host or hostgroup.
>> Look at the example.
>>
>> I have a service called disk_os which checks all filesystems
>> of a system or even a large group of systems. I do this by
>> using nrpe. To check if nrpe is running I have a service
>> called nrpe. Today I have to configure for every host with
>> disk_os a single servicedependency to nrpe.
>>
>> What I want to do is, to define that disk_os will always
>> depend on nrpe, so I don't have to mention that for each host
>> again and again.
>>
>> Thanks.
>>
>> Tobias
>>
>>
>> -----Original Message-----
>> From: "Thomas Guyot-Sionnest" <Thomas at zango.com>
>> To: "Thomas Sluyter" <nagios at kilala.nl>,"Nagios-Devel"
>> <nagios-devel at lists.sourceforge.net>
>> Date: Wed, 18 Oct 2006 23:51:25 -0700
>> Subject: Re: [Nagios-devel] Service dependencies
>>
>>>
>>> Sorry to bring up an old thread, but there were no follow
>> up on this. I
>>> just find myself in the same situation (need one-to one mapping for
>>> every hosts) and remembered this old thread.
>>>
>>> How hard would if be to add a flag in servicedependency
>> definitions that
>>> force every service dependency to reside on the same host,
>> and ignore
>>> missing services.
>>>
>>> So I could write something like this:
>>>
>>> define servicedependency {
>>>   hostgroup_name                pool1,pool2
>>>   service_description           Master service
>>>   dependent_hostgroup_name      pool1,pool2
>>>   dependent_service_description Slave 1,Slave 2,Slave 3
>>>   same_host_dependency          1
>>>   notification_failure_criteria c,u
>>> }
>>>
>>> And I'd get:
>>> 1: dependencies across services on the same host for every
>> hosts defined
>>> in pool1 and pool2
>>> 2: missing dependent services would be silently dropped.
>>>
>>> Or to be more flexible different values for
>> same_host_dependency could
>>> determine if Nagios does #1 or #1 & #2.
>>>
>>> If you don't like #2, doing #1 would already reduce
>> significantly the
>>> config required.
>>>
>>> I never checked the pre-flight code, but I'd assume it
>> shouldn't be that
>>> hard. I guess all you have to do is skip dependency creation on
>>> conditional statements.
>>>
>>> Thanks,
>>>
>>> Thomas
>>>
>>>> -----Original Message-----
>>>> From: nagios-devel-bounces at lists.sourceforge.net
>> [mailto:nagios-devel-
>>>> bounces at lists.sourceforge.net] On Behalf Of Thomas Sluyter
>>>> Sent: Monday, June 12, 2006 5:58
>>>> To: Nagios-Devel
>>>> Subject: Re: [Nagios-devel] Service dependencies
>>>>
>>>> I'm sorry if this is the second time this message gets sent to the
>>>> list. I had a hunch that it didn't make it the first time
>> I sent it...
>>>>
>>>> ============
>>>>
>>>> Hi all.
>>>>
>>>> I was actually wondering about the exact same thing Dirk
>> was thinking
>>>> about! Such a shortcut would really help out in easing the use of
>>>> dependencies.
>>>>
>>>>> Try this...
>>>>>
>>>>> define servicedependency{
>>>>> hostgroup_name windows-servers
>>>>> service_description NRPE_NT
>>>>> dependent_hostgroup_name windows-servers
>>>>> dependent_service_description Drive_C
>>>>> }
>>>>
>>>> Ethan's solution wouldn't work if you look at it logically. Why?
>>>> Because you're telling Nagios that:
>>>> * All instances of service A in hostgroup X
>>>> * Depend on all instances of service B in hostgroup X.
>>>>
>>>> Meaning that all instances of A will "fail" if -any- instance of B
>>>> goes down. That's not what we want to happen, is it? :p
>>>>
>>>> Or am I completely off on this? Might be that I'm not reading this
>>>> correctly.
>>>>
>>>> As Dirk said: it would be great if there was some shortcut for
>>>> telling Nagios that you want all instances of service A
>> in hostgroup
>>>> X to be dependant of service B on -their-own- host. That way you
>>>> could take care of all dependencies for a whole hostgroup
>> in a matter
>>>> of a few dozen lines of code.
>>>>
>>>>
>>>> - Thomas Sluyter (Cailin)
>>>>
>>>> -----------------------
>>>> This thread is located in the archive at this URL:
>>>> http://www.nagiosexchange.org/nagios-devel.33.0.html?
>>>> &tx_maillisttofaq_pi1[showUid]=18830
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Nagios-devel mailing list
>>>> Nagios-devel at lists.sourceforge.net
>>>> https://lists.sourceforge.net/lists/listinfo/nagios-devel
>>>
>>>
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>>
>> --------------------------------------------------------------
>> -----------
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>> services, security?
>> Get stuff done quickly with pre-integrated technology to make
>> your job easier
>> Download IBM WebSphere Application Server v.1.0.1 based on
>> Apache Geronimo
>> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&
>> dat=121642
>> _______________________________________________
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Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642




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