ERROR 2003 (HY000): Can't connect to MySQL server on 'x.x.x.x' (110)

[Alex Ryan]

I'm trying to establish a basic mysql connection from a google compute engine instance in one project to a google cloud sql instance (2nd generation) in a different project.

I've done this many times before without any problem. You simply add the ip address of the google compute instance to the list of authorized networks for the google cloud sql instance. This has always worked in the past but it is not working now.

The only thing that I can think of which is different about this situation is that I've recently been experimenting with using the cloudsql-proxy to establish a connection from a different gce instance to the same google cloud sql instance. Could this be the problem? Perhaps the google cloud sql instance is getting confused by having to support both connection mechanisms?

I just need the connection to work. Is there a work-around?

P.S. I followed the "rule of thumb" and posted this technical question to stackoverflow first:

https://stackoverflow.com/questions/44863898/error-2003-hy000-cant-connect-to-mysql-server-on-x-x-x-x-110

[Irina (Google Cloud Support)]

Hello Alex, 

I can confirm that Cloud SQL instance can support both connection mechanisms. In order to investigate your issue, could you send me the following information by replying privately:

1. The Cloud SQL instance name including the project ID.

2. The GCE instance name including the project ID from where you are trying to connect to Cloud SQL instance.

3. The full command that you are running to connect to Cloud SQL instance.

I’m looking forward for your response.