Cannot use custom datasource plugin as the datasource when defining the alert query in Grafana 8 alerts

In Grafana v8.0.2 with ngalert feature enabled, I am trying to define an alert rule using a custom datasource plugin I wrote. However when I select the plugin from the list of datasources, and click “Run Queries” I get the following error:
“Failed to evaluate queries and expressions: failed to execute conditions: plugin not registered”

My plugin returns a tabular dataset which is similar to the dataset in the example shown here: Grafana managed alert rules for numeric data | Grafana Labs

I am running Grafana with the following environment variables:

Hi @sahirug

I am not sure what support there is for custom datasources inside NG Alert while it is still behind the feature toggle. Might be worth trying to update to 8.0.6 to see if anything has resolved. I know the alerting squads is pushing changes very quickly…

i have the problem too.
after i running the new create datasource, in the grafana plugins is not there.
seems it’s not register success.
what can i do?