AWS RDS - Ardent

Ardent is compatible with AWS RDS for PostgreSQL. RDS needs a parameter-group change, a replication grant, and network access before Ardent can connect. Start with preflight so Ardent can tell you exactly what’s missing before it stores credentials or creates a connector. Want Claude or Cursor to help? Paste this prompt into your agent:

Check if my AWS RDS Postgres database is ready to connect to Ardent.
My connection string: [paste here]

Use Ardent preflight first:
ardent connector preflight postgresql '<connection-string>' --schemas public

Verify:
1. The endpoint is reachable from Ardent and the security group allows inbound Postgres traffic.
2. The URL points to the writable primary: SELECT pg_is_in_recovery(); must return false.
3. The DB parameter group has rds.logical_replication = 1 and the instance has been rebooted after the change.
4. The connecting role has GRANT rds_replication.
5. The Ardent preflight Grant script has been run for the schemas I want to replicate.
6. Tables selected for replication have a primary key, valid unique NOT NULL index, or REPLICA IDENTITY FULL.

After preflight passes, run:
ardent connector create postgresql '<connection-string>'

Enable logical replication

Create or modify a parameter group for your RDS Postgres major version and set:

rds.logical_replication = 1

Apply the parameter group to your RDS instance.

This requires a reboot before logical replication is actually enabled. Plan a maintenance window.

Keep enough replication slots and WAL sender capacity for Ardent plus any existing replicas or CDC tools. Do not lower existing values that other replication consumers rely on.

Allow network access

In the RDS console, open Databases > your instance > Connectivity & security and confirm the endpoint and port.Allow Ardent’s egress IP to reach the instance on the Postgres port, usually 5432. Ask your Ardent contact for the current egress IP if you do not already have it.If your RDS instance is private-only, use a BYOC environment and PrivateLink rather than opening public ingress.

Grant replication permissions

Connect as a role with rds_superuser privileges and grant the RDS replication role to the user Ardent will connect as:

GRANT rds_replication TO your_user;

Ardent may also need per-database and per-schema grants for the schemas you want to replicate. Preflight generates the exact SQL.

Run preflight

Your RDS connection string looks like:

postgresql://user:[YOUR-PASSWORD]@your-instance.region.rds.amazonaws.com:5432/mydb

Run:

ardent connector preflight postgresql 'postgresql://user:[YOUR-PASSWORD]@your-instance.region.rds.amazonaws.com:5432/mydb' --schemas public

Preflight checks reachability, credentials, source writability, logical replication, RDS replication permissions, table grants, and duplicate-source status without creating a connector or storing credentials.If preflight says the source is a read replica, use the writer endpoint instead. Ardent refuses read replicas because full-fidelity branching needs a source that can support logical replication and schema tracking.

Run the generated grant script if needed

If preflight reports missing table or schema grants, copy the Grant script section and run it in psql as a role allowed to grant those privileges.Then re-run preflight until it passes.

Connect your database

ardent connector create postgresql 'postgresql://user:[YOUR-PASSWORD]@your-instance.region.rds.amazonaws.com:5432/mydb'

Ardent stores encrypted credentials, discovers your schema, snapshots selected tables, and starts continuous replication. Initial setup time depends on data size, write rate, and network throughput.

Logical replication slots retain WAL while a consumer is behind. A very low WAL retention limit can invalidate the slot under heavy writes or long transactions, forcing a connector rebuild / resnapshot. Set retention with enough headroom and monitor long-running transactions.

Create your first branch

When the connector is ready:

ardent branch create my-feature

Done. You now have an isolated copy of your RDS database: schema, data, and all. The CLI returns a connection URL you can use anywhere.