"Overwriting" discovered items

[chojin]

In my Windows OS Template, I do services discovery and add all services that are started automatically with a trigger set to severity Warning which works nicely.

However when we want to monitor a specific application on a specific host we have a separate template for each monitored application containing among other application specific monitoring items, an item for the service_state of related windows services, with associated triggers set to higher severities than "Warning".
The idea was to "overwrite" the default items and triggers created by LLD with the ones from the template. However this seems not to be possible. If the template is assigned to the host before LLD has run, this works perfectly as LLD can't create an item that already exists.
But when LLD has already run, the template can't be applied any-more because those item(s) already exist "as an item created from item prototype."
A solution would have been to delete this conflicting item from the host and assign the template before the next LLD run. However manually deleting LLD items is also not possible...

Does anybody know a method to achieve what I have want to achieve here ?

[steveboyson]

Use regexps for your LLD and thus exclude the unwanted services from item prototype creation.

[chojin]

I already use a global regexp for filtering out 'automatic' services that are actually only run during start-up and then stop running, which is host independent.

This could be solution if I would be able to combine a global regexp with a local one on host level.
For example

Filter macro: {#SVCNAME} regexp: @Windows Services Blacklist|^service1$|^service2$

Host-level changing of the template-defined filter seems to be possible, but I assume this combining of global and local regexps won't work, as the manual states

You can enter a regular expression or reference a global regular expression in “Regexp” field.

I don't want to add host-specific services to the global regexp as this could lead to services absolutely not monitored on servers (possibly intentionally) missing the template that defines the explicit items/triggers for that service.

[steveboyson]

What about different regexps with different filter criterias at the global level?

[chojin]

That would make it very complicated and "challenging" to administer.. as I'm speaking about hundreds of hosts and many applications, sometimes together on one host, sometimes on seperate hosts etc.. all requiring custom global regexps..
:-/

[steveboyson]

Well then, what should I say ...

(You might want to think about standardization of your environment to keep it useable and administrateable? Use custom LLD scripts? Find a common criteria amongst all the hosts to define standardized LLD regexps? I don't know ;-)

[chojin]

Created a feature request to add the possibility to use global regexps inside local regexps:

https://support.zabbix.com/browse/ZBX-7960