I have an old MySQL database on AWS RDS that I need to upgrade to a newer version. I have created a blue green deployment, in order to test out the upgraded version of MySQL before switching over. But I can’t seem to connect to the green instance.

I ran a:

aws rds describe-db-instances --db-instance-identifier dbname > blue-config.json
aws rds describe-db-instances --db-instance-identifier dname-green > green-config.json

And compared the settings, and they are identical except for the CertificateDetails, TagList, DbiResourceId, DBInstanceArn, the replica settings and the version (5.7 vs 8.0).

I’ve looked at the security groups etc and they both have the same inbound rules. I can connect to the blue one, but running the same command for the green one times out after 60 seconds with:

ERROR 2003 (HY000): Can't connect to MySQL server on '[dbinfo.host].rds.amazonaws.com:3306' (60)

Any ideas how to proceed with this? :/