I recently downgraded my EC2 instance. I can no longer connect to RDS. I think it might be that the internal IP is different and now the logins are attached to that specific IP. I haven't been able to figure it out. I would like to be able to get a backup from the snapshot. Is there a way to download it through AWS?
You can't download an RDS snapshot. You can however connect to it and export your databases. Downgrading your instance should not affect connectivity unless you had set up your security groups incorrectly (Opening ports to an IP instead of another security group).
In addition to datasage answer.
As an option for production instance you can create a readonly replica in RDS and make dumps from this replica. You could avoid freezing of production DB this way.
We use this scheme for PostgreSQL + pg_dump. Hope it will be helpful to somebody else too.
It sounds like your RDS is within a VPC inside a private subnet with security group and ACL. The only way to solve your issue is to take a snapshot and cerate a new DB instance out of it within the default VPC where all connections are allowed. After that you take backup classic backup using a db client or CLI.
Another option is to share your snapshot if you don't need to download it and just want to share it with a different AWS account ID.
I also needed to do this so I created a dump of the db (MySQL) by logging into my app server which has permissions to access the db. I then downloaded the dump to my local machine using scp. I used:
mysqldump -uroot -p -h<HOST> --single-transaction <DBNAME> > output.sql
来源：https://stackoverflow.com/questions/14916899/download-rds-snapshot