This post explains how to set custom Elasticsearch configuration within Warden to fix the Fielddata access on the _id field is disallowed error with Elasticsearch 8.
This is a follow on from a earlier post explaining common ES8 configuration issues with Magento.
The error was are going to fix related to ES8 changing the default values for _id fielddata
Fielddata access on the _id field is disallowed, you can re-enable it by updating the dynamic cluster setting: indices.id_field_data.enabled"
The Solution
Within your project root create a file at .warden/warden-env.yml with the following content
version: "3.5"
services:
elasticsearch:
environment:
- indices.id_field_data.enabled=true
Now restart your warden environment warden env restart, followed by a reindex warden shell -c "php bin/magento index:reindex; php bin/magento c:f" and voila, you should now have a catalog again!