Ring topology parent/child relation Nagios

[Hugo van der Kooij]

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Mihai Tanasescu wrote:
|> This problem should not exist.
| Nagios --> Router A  --> Router B uplink1+2 ring (and Router B is in a
| ring topology which closes in it)
|
| http://tinypic.com/view.php?pic=11uhx7a&s=3 (this is the logical layout)
|
| Yes. But if you cut the 2 uplinks from Router B, then the Nagios machine
| will see Router B as up but will not be able to reach any other router
| from the ring and will thus alert that all other routers are down (which
| is not true).
| I mean having split the ring into the 2 halves you suggested that:
| C has parent B, D has parent C, E has parent D
| G has parent B, F has parent G
| => B up but B uplinks to C and G down -> alerts that C and G are down
| although they aren't
|
| Can this be eliminated ? (I'm sure the solution should be simple and
| obvious but I'm not being as careful as I should to see it)

A ring config is a nightmare from the perspective of Nagios. The maths
simply do not work. The whole parent concept does not work for a ring.
The best you can do is some half way concept that will never show the
proper state in all cases.

Building a config to keep the amount of down reports to a minimum is not
a simple thing. The key is to cut thing in half and make sure you get
the timing right. Each node further away must wait longer to go from
soft fail to hard fail state. The manual handdles that subject and it is
mandatory to read it before you even try to use the parent feature.

So either spend many hours in perfecting a model to get a half way there
solution or accept the extra down reports and learn to interprete them
as an exact way of telling where you ring did break up.

There is no simple solution.

Hugo.

- --
hvdkooij at vanderkooij.org               http://hugo.vanderkooij.org/
PGP/GPG? Use: http://hugo.vanderkooij.org/0x58F19981.asc

	A: Yes.
	>Q: Are you sure?
	>>A: Because it reverses the logical flow of conversation.
	>>>Q: Why is top posting frowned upon?

Bored? Click on http://spamornot.org/ and rate those images.

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