AWS RDS & AWS Aurora

Prerequisites

• If your Postgres database is protected by security groups or other firewall settings, you will need to have the data syncing service's static IP available to complete Step 1.

Step 1: Allow access

Allow write access to a portion of your RDS or Aurora PostgreSQL database.

Configure the Security Group

1. In your Amazon RDS > Databases list, click the PostgreSQL instance you want to send data to.
2. In the database page, in the Connectivity & security tab, make note of the Endpoint and the Port number.

3. In the Security section, ensure that set the Publicly accessible setting is set to Yes to ensure that the destination is accessible from outside your VPC. Note that it is still only accessible through whitelisted IPs at this point. If connecting via SSH tunnel, this can be set to No.

4. Click one of the VPC security groups (usually default). Note: VPC groups are permissive (vs. restrictive) and for instances with multiple VPC security groups, only one needs to be configured with the new inbound rule.

5. In the Security Groups section, select the Inbound rules tab.
6. Click Edit inbound rules and then click Add rule.
7. Edit the newly created rule of type Custom TCP with the Port range noted in the first step (usually 5432) and a Custom Source value that includes all of the service IPs. Note: you will need to add /32 to the end of each IP (CIDR notation). If connecting via SSH tunnel, use the bastion server's security group as the Source instead.
8. Click Save rules.

Configure network ACLs (access control list)

For database instances in a VCP

1. In your RDS dashboard, select the PostgreSQL instance.
2. Click the link to the instance's VPC.
3. Click the VPC ID.

4. In the Details section, click on the link under Main network ACL.

5. Click on the network ACL ID.

Edit the inbound rules

6. Click on the Inbound rules tab, and check if there is an existing rule with a Source of 0.0.0.0/0 set to Allow. (This is a default rule created by AWS. If this rule already exists, skip to Edit outbound rules.)

7. Create the inbound rule (if it doesn't exist). Click Edit inbound rules and either Add new rule or edit an existing rule to allow access to the port number of your database instance (usually 5432) from the Prequel static IP. Click Save changes.

Edit the outbound rules

8. In the ACL menu, select the Outbound rules tab, and check if there is an existing rule with a Destination of 0.0.0.0/0 set to Allow. (This is a default rule created by AWS. If this rule already exists, skip to the next step.)

9. Create the outbound rule (if it doesn't exist). Click Edit outbound rules and edit the rules to allow outbound traffic to ports 1024-65535 for Destination 0.0.0.0/0.

Optional: SSH tunneling

If your database is not publicly accessible, SSH tunneling through a bastion host is supported.

1. Allow inbound SSH (port 22) from the static egress IP on the bastion host's security group.
2. On the bastion host, create an SSH user and add the service's public key to ~/.ssh/authorized_keys. Contact support to obtain the public key.
3. Add the bastion host's security group to the database's inbound rules (in place of the static egress IP — see step 7 above).
4. Supply the bastion host address, port, and username when configuring the destination.

Step 2: Create writer user

Create a database user to perform the writing of the source data.

1. Open a connection to your Amazon RDS PostgreSQL database.
2. Create a user for the data transfer by executing the following SQL command.

CREATE USER <username> PASSWORD '<some-password>';

3. Grant user create and temporary privileges on the database. create allows the service to create new schemas and temporary allows the service to create temporary tables.

GRANT CREATE, TEMPORARY ON DATABASE <database> TO <username>;

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If the schema already exists:

By default, the service creates a new schema based on the destination configuration (in the next step). If you prefer to create the schema yourself before connecting the destination, you must ensure that the writer user has the proper permissions on the schema, using GRANT ALL ON schema <schema> TO <username>;

Step 3: Add your destination

Use the following details to complete the connection setup: host name, database name, port, your chosen schema name, username, and password.

Permissions checklist

• RDS security group inbound rules allow the service's egress IP on the configured port (usually 5432). If using SSH tunneling, allow the egress IP on port 22 on the bastion host's security group instead.
• Network ACL inbound rules allow traffic on the configured database port; outbound rules allow ports 1024–65535.
• Database user has CREATE and TEMPORARY on the target database.
• If using a pre-created schema: user has GRANT ALL ON SCHEMA <schema>.

FAQ

Q: How is the Aurora PostgreSQL connection secured?

A: We connect using the credentials you provide over TCP. Access is restricted by the RDS security group inbound rules, which should allow only the service's static egress IP on the configured port. SSH tunneling through a bastion host is supported for databases not publicly accessible.

Q: What Aurora PostgreSQL versions are supported?

A: Aurora PostgreSQL compatible with PostgreSQL 13 and above are fully supported. PostgreSQL 12-compatible versions are best-effort only.

Q: Do I need to pre-create the schema?

A: No. The schema provided in the destination configuration is created automatically on first sync. If you pre-create it, grant ALL on the schema to the writer user and you may remove the database-level CREATE permission (retain TEMPORARY).