Unable to enter create read replica page for a MySQL RDS instance inside classic EC2

Question

I have an old MySQL RDS instance, and it is currently in classic EC2.  Since this week, I've been keep seeing following error when trying to enter the **Create Read Replica** page on RDS Management Console:

```
Cannot read properties of undefined (reading 'VpcId')
```

Does anyone know what this error is about and how to get rid of it ?

Accepted Answer

For people who encountered this error, I believe this is an error in Management Console. Before they fix this, you can create a read replica for a RDS instance in EC2 Classic properly with AWS command line.

Example Command:

```
aws rds create-db-instance-read-replica --profile xxxx --db-instance-identifier xxx  --source-db-instance-identifier xxx  --db-instance-class db.m3.medium --storage-type standard --no-multi-az --publicly-accessible --no-auto-minor-version-upgrade
```

Command Reference:

https://awscli.amazonaws.com/v2/documentation/api/latest/reference/rds/create-db-instance-read-replica.html

Answer

The VpcId is the identity of the VPC to create the replica within. It is possible that the engine version you are using is not supported in EC2 Classic. See the documentation for determining this. You may have to move your RDS to a VPC.

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.WorkingWithRDSInstanceNotinaVPC.html

Unable to enter create read replica page for a MySQL RDS instance inside classic EC2

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