Issue with creating a Postgres RDS in Cloudformation Template


I have the following YML in my cloud formation template:

It is failing due to “The DB instance and EC2 security group are in different VPCs. The DB instance is in vpc-7c99881b and the EC2 security group is in vpc-34ef9c4d”

I tried adding a DBSecurityGroup

and changed the MyDB:

but it now says “EC2 security group sg-7debfb0c is in a different VPC vpc-34ef9c4d. It cannot be authorized to RDS DBSecurityGroup dbsecuritybyec2securitygroup-1whvh0xi93cke for VPC vpc-7c99881b.”

vpc-34ef9c4d is the vpc i am wanting this RDS in, how do I specify which VPC the DB should be located in?

Updated Template:


Use DBSubnetGroupName ( That determines the VPC. If nothing is specified, RDS is created in the default vpc

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