Requirements: redis server running (via docker , service in the computer or remote) ability to stop the redis server. Steps: Run redis locally via docker (or normal service in the computer if you've it already): docker run --net-host redis Create a redis cache instance in Moodle: Site admin -> plugins -> caching -> configuration Under 'Installed cache stores", next to Redis, click "Add instance" Enter 127.0.0.1:6379 in the server field and save Confirm that it shows as "ready" under "Configured store instances" (the second table on the page) Kill the redis server (just Ctrl + C the running container, or stop the service if running locally) Go back to the cache page and reload. Confirm that you don't see an error message (either "Connection refused" or "getaddrinfo failed" depending on what you did in step 2) Confirm that your redis instance is not marked as ready (Check under the "Configured store instances" section)