I am working on setting up PgBouncer on Google Compute Engine (GCE) instances to manage connections to a Cloud SQL PostgreSQL database. My setup involves multiple databases hosted on the same Cloud SQL instance, and I have some security and user management concerns that I would like to address.

Here’s a brief overview of my current setup:

• Google Compute Engine (GCE): Hosting PgBouncer.
• Cloud SQL: PostgreSQL database with multiple databases on the same instance.
• User Management: I need to handle multiple database users with different access levels.
• Security Concerns: Ensuring secure communication between PgBouncer on GCE and Cloud SQL, as well as managing access controls for multiple databases and users.

My specific questions are:

1. Security Best Practices: What are the recommended security practices for securing the connection between PgBouncer on GCE and Cloud SQL? Should I use SSL/TLS for encrypting the connection, and if so, how can I properly configure it?

2. User Management: I am using different database users for access control, but when using a service account for PgBouncer, I am unable to handle these users effectively. How can I manage multiple database users with varying access levels while using PgBouncer? Are there specific configurations or workarounds for this?

3. Access Control: How can I manage access controls effectively when dealing with multiple databases and users on the same Cloud SQL instance? Are there specific PgBouncer configurations or Cloud SQL IAM policies that I should implement?

4. Performance Considerations: Are there any performance implications or best practices I should be aware of when using PgBouncer with multiple databases and users on a single Cloud SQL instance?

5. Troubleshooting: Are there common pitfalls or issues that I should watch out for during this setup, especially related to user management and service accounts?

I have reviewed the official documentation for PgBouncer, GCE, and Cloud SQL, but I would appreciate any insights, best practices, or examples from the community to ensure a secure and efficient setup.

Thank you in advance for your help!