topic Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ? in Dynatrace Managed Q&A

Automatic tag on custom device based on "issameis" OneAgent Host placeholder

nicolasT123 — Mon, 05 Jan 2026 12:29:05 GMT

Hello,

I am on a managed cluster.

I use the PostgreSQL native extension.

It creates two differents CUSTOM_DEVICE for one Databases servers.

I got the OneAgent installed installed and can see on the custom_device that it attachs the real monitored host.

On my host, I got properties.

How could I create a automatic tag value on the Custom device, based on a OA host property value like

"{Host:Environment:myenv}"

And associate to the Custom_device entity selector :

I tried this without success :

type(CUSTOM_DEVICE),fromRelationships.issameas(type("HOST"))

Is it possible to inherit a placeholder value from a different entity type ?

Thanks in advance.

Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ?

AntonPineiro — Tue, 19 Aug 2025 19:20:51 GMT

Hi,

I would say transform that host property in a tag in host level, using automatic tagging rules. And later, propagate tag from host to custom device.

You need to check topology to understand how custom device is linked to host:

You can try to create a tagging rule, using entity selector, using "run_as" to "sql:postgres_host".

Best regards

Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ?

nicolasT123 — Wed, 20 Aug 2025 08:02:13 GMT

Hello, I was able to create the good entity selector :

type(sql:postgres_host),fromRelationships.issameas(type("HOST"))

The display entities is able to catch my host.. But the placeholder "{Host:Environment:myenv}" is not translated to its value and remains "raw : {Host:Environment:myenv}" on the custom devices tag :

(here another example screenshot but the philosophy is here)

precision : My metadata (host properties) is working fine because I use it to propagate tags from values to process groups and services.

What do you mean by propagate from "host tags" to "custom devices" tags ? You mean manually ? Or is there a way to make it automatic ?

If manual, any new configuration of the extension will have to be followed by a manual tag propagation which is not smart at all.

Thanks for your help.

Best regards.

Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ?

AntonPineiro — Wed, 20 Aug 2025 11:55:57 GMT

Hi,

It means manually. Imagine you have tag "X". Then you can use "type(sql:postgres_host),fromRelationships.issameas(type("HOST"),tag("X"))" as selector to new tagging rule.

This product idea is to avoid manual stuff. It would be good if those tags are autopropagated to custom devices as default.

Best regards

Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ?

parkash_jha_746 — Tue, 23 Sep 2025 14:46:12 GMT

Hi @AntonPineiro ,

We are trying to tag our OS service custom device with hostname for e.g. (host: <hostname>).

We have the hostname available on the metadata of the OS service however we are not able to write a query of entity selector which can tag the custom device with hostname. Could you please help on this.

Regards,

Parkash

Re: Automatic tag on custom device based on "issameis" OneAgent Host placeholder ?

AntonPineiro — Tue, 23 Sep 2025 14:50:00 GMT

Hi,

You can follow this approach.

Best regards