Migrate Aurora DB from one VPC to another

Question

We have 4 standalone, non-multiAZ aurora DB instances in a VPC and we want to move them to aurora instances in another VPC.

As I understand there are 3 ways to migrate DB instances:

1) Modify the DB instance's Subnet group to change the VPC.

However this is not supported for Aurora instances yet.

2) Create a read replica, and when slave catches up, stop the slave and take it's snapshot to create a DB instance in the different VPC and use external slave then to again resume the replication.

I have a few question around this second method. As Aurora is using some different
replication method, the result of show slave status; command is empty.
Also by default the binlog_format is OFF so not sure if I have to modify it and
then restart the instance to take note of the binlog etc.

Have anyone done this before and can guide me? I don't want to restart the instance
to later find out that it is not working, as it is a very critical DB and I want to 
minimize the downtime.

3) Use Amazon DMS service, however I cannot find the source DB details for Aurora in the documentation here.

I need to find out what all permissions to give to the replication user
I'll create for this. This command in aurora is not working,
GRANT REPLICATION CLIENT, REPLICATION SLAVE ON . TO 'replication_user'@'%'
IDENTIFIED BY 'aaaaaa';

Any help would be appreciated.

user_3069919 · Answer

Create a snapshot and restore it to a new cluster. When you do that, use a new subnet group created for the second VPC. That's the best way to achieve this. Like you called out, you cannot change subnet group for an existing cluster.

In your approach #2, you mention having to create a slave and then taking a snapshot. That's not required. All instances in a cluster are connected to the same shared volume, so you can just go ahead and create a snapshot from your single instance cluster directly. Just make a note that snapshots are a cluster level action, and not an instance level action in Aurora.

user_1619555 · Answer

From https://aws.amazon.com/premiumsupport/knowledge-center/rds-vpc-aurora-cluster/

It states that

Create a clone in a different VPC

If you clone a database in an Aurora cluster, you can change the VPC of the clone. > However, the subnets in the VPC must map to the same set of Availability Zones. For more information, see Cloning Databases in an Aurora DB Cluster.

It does work though can't see a way via the console to break the replication. We are using this as a faster way of migrating than snapshot and restore. Stopping the original master would break replication but though you could do it cleaner

Migrate Aurora DB from one VPC to another

3 Answers