Improving the host <parents> logic

[Andreas Ericsson]

Shane Stixrud wrote:
> 
>>> Sure this works fine when the switch is isolated to one layer 3 
>>> network (i.e. no vlans).  Care to share the magic tricks you use to 
>>> tie vlan assigned switch ports to the correct layer3 
>>> devices/interfaces??
>>
>>
>>
>> Sure. Give the switch an IP in each network and make it switch2-vlan23 
>> or, if the route goes through the same physical devices no matter the 
>> VLAN, use whatever IP you already have on it. Obviously, this doesn't 
>> work if you can't set an IP on the switch and it can't respond to ICMP 
>> or some such (in which case you almost certainly won't have VLAN's on 
>> them).
> 
> 
> Are you serious?  You consider this the Right Thing (TM) compared to 
> having the ability of defining the layer2 and layer 3 parent for each 
> device?


Yes. Most problems I've seen with VLANs doesn't so much have to do with 
the management network or physical device being down, but rather that 
one or more interface either breaks or go out of tune for one reason or 
another. Checking the management interface in such cases only catch a 
few of the possible errors.


>  Please be serious, the amount of extra work here is absurd, 
> especially considering the only benefit is an accurate 3d map and 
> notification suppression in Nagios.  I dunno what switches you are using
> but Cisco switches have a management interface that is normally attached 
> to the management VLAN.


If it's a member of the management VLAN then ofcourse it has an 
interface there. Or are you talking networks and IP-addresses?

Since you asked: I've used HP, Nortel, Extreme, D-Link, Cisco, Netgear, 
Zyxel, TekComm (don't use those), 3Com and Linksys.

All of those, with the exception of TekComm, supported multiple 
IP-addresses. All of them also had the option of only serving tcp and 
udp-based services on one IP only.


> 
> It sounds like you are defending the current implementation not because 
> its the best solution but because thats what exists.  Even if these 
> issues didn't exist with your "approach" it would still be worth 
> changing to cut down the configuration complexity and management 
> overhead required. My suggestion is just that a suggestion, if nagios as 
> a project is not interested in it thats fine, but your dismissal of this 
> real issue is unwarranted IMO.
> 

"Nagios as a project" means Ethan. I have no influence what so ever what 
code gets in and what doesn't. I doubt if Ethan will write the code for 
this though, so if you want it in you should start hacking right about now.

>> So each host would have parents, l2parents and l3parents??
> 
> 
> Every inter-network device has at least one layer 2 connection and at 
> least one layer3 interface.
> 

An answer worthy of the microsoft support staff. Completely accurate 
while avoiding the question, rendering it totally useless.

A straight answer, if you please; Do you intend for host-objects to 
support the three configuration directives "parents", "l2parents" and 
"l3parents"?


I think the best way to convince everybody that you're right would be to 
make a configuration with the current capabilities, write a patch for 
the l[23]parents directive (testing it thouroughly, ofcourse) and then 
sending a diffstat of the code and configuration changes along with the 
patch.

I recommend you to import the CVS repo to git or some other scm with 
decent branch support before you start though.

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231


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