We are not getting results from CPU Usage API

[ShashiP]

Hi DT Community,

We have situation where we are not getting results from CPU Usage API Response, the data array is empty. This issue started recently where our machines are migrated from DVWT to RAVW.

If you ask me how we gets the data from API Endpoints, the answer is, we provide Host-Identity ID to the CPU Usage API. I can see Host Identity ID as well for RAVW machines and can see CPU details on Dynatrace Dashboard UI but not able to see any results of API consumption.

Appreciate your help and time.

[t_pawlak]

Hi,
this usually points to using the wrong identifier in the metric query after the migration.
For builtin:host.cpu.usage, Dynatrace Metrics API v2 expects the Dynatrace host entity ID (HOST-...) in entitySelector, for example:
entitySelector=type("dt.entity.host"),entityId("HOST-XXXXXXXXXXXXXXX"). Dynatrace shows this exact pattern in the Metrics API examples for host CPU usage. So if your script is still passing an older “Host-Identity ID” from DVWT, while the host in RAVW now has a different/current entity context, the API can return an empty data array even though CPU data is visible in the UI. The UI resolves the current entity, but the API query must target the correct current host entity ID. 
To resolve it, check in UI (in URL) that you have correct HOST-ID.
I am pretty sure that the host identifier used by the API is no longer the right one after the DVWT to RAVW migration