Configure S3-compatible access for ASP.NET Core

Summary

Object storage client for a ASP.NET Core app on Ample. Verified on ASP.NET Core: bucket credentials delivered as encrypted S3_* environment variables and a validated PutObject/GetObject round-trip linked to a database row (upload=ok linked=ok). Build and start: dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT.

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.)
• S3-compatible object storage: verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)

Prerequisites

• A ASP.NET Core project (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT)
• A bucket from ample bucket create with credentials passed as encrypted S3_* environment variables
• An Ample account token with servers:write, buckets:read

Exact tested configuration

• template: dotnet-10
• runtime: dotnet
• size: s-1vcpu-1gb
• build: dotnet publish -c Release -o out
• start: ASPNETCORE_URLS=http://0.0.0.0:$PORT dotnet out/$(basename $(ls out/*.runtimeconfig.json | head -n 1) .runtimeconfig.json).dll

Steps

1. Build and start. dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT; the server must bind 0.0.0.0 on PORT.
2. Create the bucket and pass its credentials. Create it once with ample bucket create, then pass endpoint, region, bucket and keys with --env; use path-style addressing.

   ample deploy . --name <app-name> --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...

3. Verify. Fetch the live URL and /p/browser-file-uploads on the example; on failure read the build and runtime logs.

   ample logs <deployment_id> --kind build

Tested examples

• ASP.NET Core pattern fixture (tests/deploy-canaries/asp-net-core-patterns): Verified object storage client on ASP.NET Core.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary asp net core patterns)
• browser-file-uploads check from the example (/p/browser-file-uploads on the live URL, expect see the pattern fixture checks)

Limitations

• Verified on the dotnet-10 template at s-1vcpu-1gb; other sizes and ASP.NET Core major versions are not verified.
• Region, compliance attestations and request-duration limits are unknown and not claimed.
• PutObject and GetObject with path-style addressing are verified; other S3 operations are not.

Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

• app server x1 s-1vcpu-1gb: 5.00 USD

Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

Verification evidence

• canary_run on 2026-09-21T01:15:54Z at revision 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21): ASP.NET Core pattern fixture deployed on Ample (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT); for this guide: bucket credentials delivered as encrypted S3_* environment variables and a validated PutObject/GetObject round-trip linked to a database row (upload=ok linked=ok). (expires 2027-03-20T01:15:54Z)