Migrate AWS EC2 app: FastAPI

Summary

Move FastAPI compute from AWS EC2 app to Ample, one component at a time. Destination verified on Ample: the app built, started and answered on its public HTTPS URL with encrypted configuration delivered. Source procedure: Collect the process environment from the instance (systemd unit or process manager config) into an env file kept out of the repository. Not migrated automatically: Cron jobs, local files on the instance disk, security-group networking and IAM instance roles are not migrated; use managed databases, buckets and encrypted env instead. Cutover: Add the custom domain with ample domain add, update DNS from the instance or load balancer, keep the instance until verified, then stop it. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

Infrastructure requirements

• Compute: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
• Postgres: verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)

Prerequisites

• Authorized access to the AWS EC2 app source and its export tooling
• An inventory of every component in scope and out of scope
• A validated backup or copy before any cutover
• An Ample account token with servers:write, databases:read

Exact tested configuration

• template: python-3.12
• runtime: python
• size: s-1vcpu-1gb
• install: python3 -m pip install --target .ample/python -r requirements.txt
• start: PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 run.py

Steps

1. Inventory the source. List what AWS EC2 app provides beyond the component you are moving. Out of scope here: Cron jobs, local files on the instance disk, security-group networking and IAM instance roles are not migrated; use managed databases, buckets and encrypted env instead.

2. Source step 1. Collect the process environment from the instance (systemd unit or process manager config) into an env file kept out of the repository.

3. Source step 2. Replace the instance's process manager with the repository's start command; Ample supervises the process and restarts it.

4. Source step 3. Inventory what else runs on the instance: databases, cron, reverse proxy rules, local files.

5. Deploy on Ample in parallel. pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template. Pass the exported variables with --env; keep the source running.

   ample deploy . --name <app-name> --public --start "python3 run.py" --env-file .env.production
   

6. Validate before cutover. Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/configuration-secrets, /p/relational-records).

7. Cut over. Add the custom domain with ample domain add, update DNS from the instance or load balancer, keep the instance until verified, then stop it.

8. Rollback. Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

Tested examples

• FastAPI pattern fixture (destination) (tests/deploy-canaries/fastapi-patterns): Verified destination basis: FastAPI compute.

Success checks

• destination app responds on its public URL (/ on the live URL, expect ample canary fastapi patterns)
• configuration-secrets check from the destination example (/p/configuration-secrets on the live URL, expect see the pattern fixture checks)
• relational-records check from the destination example (/p/relational-records on the live URL, expect see the pattern fixture checks)
• data or object counts and checksums match the source

Limitations

• Documentation only: nothing is executed automatically and no execution binding is offered.
• The source-side procedure is documented from AWS EC2 app's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
• No full source-product parity is claimed: Cron jobs, local files on the instance disk, security-group networking and IAM instance roles are not migrated; use managed databases, buckets and encrypted env instead.
• Verified on the python-3.12 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures on the managed side are not verified beyond the pattern checks.

Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

• app server x1 s-1vcpu-1gb: 5.00 USD
• managed PostgreSQL database x1 s-1vcpu-1gb: 5.00 USD

Verification evidence

• canary_run on 2026-09-21T01:14:18Z at revision 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21): Destination side verified: the FastAPI pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template) and its checks passed (the app built, started and answered on its public HTTPS URL with encrypted configuration delivered). The source-side export from AWS EC2 app is documented from the vendor's standard tooling and was not executed by this catalog's evidence. (expires 2027-03-20T01:14:18Z)

Last verified: 2026-09-21T01:14:18Z

Execution binding

No execution binding. This recipe is documentation only; nothing is executed automatically.