[Solved] Anyone using Flarum with Google Cloud SQL?

Stuck on the Install Flarum page, error said:

Something went wrong: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known

MySQL host is: "/cloudsql/{{connection string}}"
While connection string is the Instance connection name from Cloud SQL

Flarum is installed on usual VM instance. (not App Engine)

I figured this out myself.

Install this on the server that running Flarum.

Then for MySQL host, just use 127.0.0.1