BI: parameter in a regex

General
1

Hellows!
TL;DR: How can I use a parameter in a regex? $param$\d.example.com does not work. Adding 1 or 2 backslashes does not work either

I need to set up a BI Aggregation for some clustered services. The setup looks like this:
Three-ish servers, which have numbered hostnames

email1.example.com
email2.example.com
email3.example.com

and a Loadbalancer with the same name, but no number.
email.example.com

We use this naming-schema for multiple services (LDAP, WEB, …) and I wanted to create rules with parameters. The aggregation is a very flat tree:

Service $service="email"$ is available (Worst status of all children)
|--> Loadbalancer $service="email"$ (Worst)
|--> Cluster nodes $service="email"$\d (Worst, but limited to WARNING)

So I tried to set up a rule and set the Child Node Generator to Create Nodes based on a host search to capture the numbered cluster-hosts but it wants a regex, which seems to be incompatible with $parameters$ due to the dollar sign.

image

Is that correct or is there a trick to use parameters in regexes?
I was unable to find any reference and surfing the cmk code is too hard for me.

Cheers!
chris :slight_smile:
edit: add screenshot

2

Hello,
have you tried to create parameters for SERVICE and NUMBER?
Then the regex should look like: $SERVICE$$NUMBER$.example.com

Karl

3

Hello,
somethin like this works also: $MYPARAM$[0-9].example.com

Christian

4

Karl, Christian, thanks for the answers!

Alas, even with them I don’t get this to work. I documented the whole setup in this poster.

image
image3261×1840 986 KB

I hope it goes through in full resolution. Otherwise I’ll think of something and edit this post.
I just wonder how a dollar-sign, which means “end-of-line” in regular expressions, can be used here without some magic.

1 Like
5

Did you try $HOSTNAME$ or $1$ for the Host itself form search result. This is what described in the Help of the Rule.

6

Aha. Thank you Christian. That put me on the right track.

I’ve been playing around and seen some funny things.
So these are my experiment-notes. First line is the Hostname Regex, second line is Nodes to create and third line is the result. To start my fun result without a parameter:

* "all hosts"
+ email\d.*
= 156 (!) nodes, 52x email1-3 - one for each of the 52 hostnames in the database.

* .* (which is effectively "all hosts")
+ email\d.
= 3 correct nodes
-> "all hosts" is not the same as "regex .*"

Now with the parameter. I’ll start with the correct answer and then add all my failures.

* $SERVICE$([0-9]).example.de
+ $HOSTNAME$
= Perfect result. but why?

* $SERVICE$[0-9].sim.lrz.(de)
+ $HOSTNAME$
= 1 correct host. seems like it kind of matters where the parens go.

* $SERVICE$[0-9].example.de
+ $HOSTNAME$
= 1 correct host. number one: email1.example.de - 2 missing

* $HOSTNAME$
+ $SERVICE$[0-9].example.de
= nothing

* $1$
+ $SERVICE$[0-9].example.de
= nothing

* $SERVICE$[0-9].example.de
+ $1$
= nothing

* ($SERVICE$[0-9]).example.de
+ $1$
= nothing

* ($SERVICE$[0-9]).example.de
+ $1$
= nothing

* $1$
+ ($SERVICE$[0-9]).example.de
= nothing

* $SERVICE$([0-9]).example.de
+ $SERVICE$$1$
= nothing

* $SERVICE$([0-9]).example.de
+ $HOSTNAME$$1$
= nothing

Now for some other fun: The same thing, but for services!
So far, I’ve been able to produce hosts with “Create nodes based on a service search”:

Create Nodes based on a service search
+ regex for host name 
+ nodes to create host - empty is not allowed
service regex is empty with the non-parameterized rules.
non-parameterized rules have "regex for host name" and "nodes to create host" the same value


+ $service$([0-9]).example.de
+ $HOSTNAME$
= added 3 host nodes. not a single service.

+ $service$([0-9]).example.de
+ same 
= nothing

+ $service$[0-9].example.de
+ same 
= nothing

+ $service$([0-9]).example.de
+ $1$
= nothing,

+ $service$.*
+ .*
= 52 different host entries. each server in the database.

+ $service$.*
+ same
= nothing

Any idea what is going on here?
Cheers!
chris :slight_smile:

7

I would like to prefer to call a rule to detect the needed services for the host from host serach. If you want more than one service you can use a pipe like “CPU.*|Memory.*” and so on.

Regards,
Christian

8

I give up. I cannot get it to work and so I have decided to create all my (honestly few) rules manually.
Thank you for all your time. :+1:
chris