Dependent items unsupported without consequence

[vaX'en]

Hey guys!

I'm affected by very weird problem. I'm running Zabbix 3.4.2 and started to monitor amavis. I made general item to collect text from interresting me command (amavis-agent -c 1) and dependent items on it, to preprocessor that huge text for wanted lines. Aaaand... Some of items work correctly (those lines exists in text). Problem starts, where items look up for lines, that don't exists. Part of those are unsupported with error below:

Value "" of type "string" is not suitable for value type "Numeric (unsigned)"

and, in my opinion, it's ok, 'couse ZBX don't count them as unsupported really. Thereafter sort of them are with huge error, that starts with:

Item preprocessing step #1 failed: cannot perform regular expression match on value "my huge text to search for lines"

.

I have no idea why part of them are with one error, and rest with second. Both are very similar:
Preprocessing steps:
1. Regular expression | LookedLine;(.*) | \1
2. Right trim | /h
(chars for right trim are because the value is in "per hour" units, and I want to collect only intereg number and add units later in item configuration)

Hope someone will find way to solve this, everything started after update to 3.4.2 from 3.4.1...

If you have any question I'll try answer, but my language isn't very well

[andris]

https://support.zabbix.com/browse/ZBX-12500 could be related.

[vaX'en]

I'm afraid it won't work. My problem is duality of errors. I tried linked issue by you, didn't worked... Anyway thank you for help

[vaX'en]

I'm not sure, but it didn't helped. Still I got two types of error with unsupported items (1. empty value and 2. preprocessing error). Is there any way to make those unsupported working again? I mean - is it possible to set value of item to zero when it's empty string?

[adammir]

Hi,
I have run into same situation like it's described by VaX'en.

I think, that the solution that was choose in https://support.zabbix.com/browse/ZBX-12500, for this issue is partially wrong. Please note that if item is unsupported, and if you do not monitor on zabbix how many unsupported items You have, you wont be able to know if there is an issue at all. Also if you monitor unsupported items, you may receive false alerts that items are unsupported.

In case of commands, that may return differ output on each server (such situation happens with amavis-agent -c 1), where item is propagated via template assigned to differ hosts in zabbix, it causes lot's of issues.

In this case there should be a possibility, to set default value if item is not supported (value that we try to check is not there at this time, but may appear in next 5min or 1day - do not matter).

Below I present example situations where dependent item, that is based on master item which takes output from command amavis-agent -c 1:

Example of possible situations:
- on server A at 1:10 item is checked and there is a value for item P1
- on server B at 1:10 item is checked and there is a value for item P1
- on server C at 1:10 item is checked and there is no value for item P1 - item is unsupported - here it should return 0 instead

- on server A at 1:15 item is checked and there is a value for item P1
- on server B at 1:15 item is checked and there is no value for item P1 - item is unsupported - here it should return 0 instead
- on server C at 1:10 item is checked and there is no value for item P1 - item is unsupported - here it should return 0 instead

- on server A at 1:20 item is checked and there is a value for item P1
- on server B at 1:20 item is checked and there is a value for item P1- item again is supported
- on server C at 1:10 item is checked and there is no value for item P1 - item is unsupported - here it should return 0 instead


For above please assume that item P1 started to work at 1:10, and there is no history prior that time. Server A, B and C got assigned same Template that gathering master item, and dependent item P.
On server C item P probably wont be occurring at all - or it may appear in week or so.
On server B item P is periodically not shown in master item - as command is not printing it at all, cause of no data there is to be shown
On server A item P is gathered all the time - but it also may not appear in future for some reasons.


I think that this clearly shows where is issue. If someone got some solution for it please write.