Diagnose deployment failures for ASP.NET Core

Summary

Deployment diagnostics for a ASP.NET Core app on Ample. Verified on ASP.NET Core: the same app deployed with a deliberate boot failure (CANARY_FAIL=boot): ample deploy exited 1 with a coded failure (health_check_failed when the process dies at boot, public_ingress_failed when the framework boots but every request answers 500) and the app's own error line was readable with ample logs <deployment_id> --kind runtime, so the cause is read from the framework's output rather than guessed. 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.)

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)
• An Ample account token with servers:write

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. Read the failure code. Deploy is synchronous. Exit 1 with build_failed means the isolated build failed; health_check_failed means the app built but never answered on PORT (it crashed at boot or bound the wrong port); public_ingress_failed means it answered on PORT but the public URL returned an error status (a request handler or bootstrap failed); exit 2 means a required preflight action is blocking.
2. Read the build log. The last lines name the failing command and its output.

   ample logs <deployment_id> --kind build

3. Read the runtime log. For health_check_failed the runtime log carries the ASP.NET Core process output: in the verified run the deliberate boot failure's own error line was there, followed by the platform's health-check verdict and the start command it ran.

   ample logs <deployment_id> --kind runtime

4. Fix and redeploy once. Change the source, the environment or the command override, then run ample deploy again. Do not loop deploys to poll status; an unchanged redeploy is a no-op.
5. Verify. Fetch the live URL 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 deployment diagnostics on ASP.NET Core.

Success checks

• failed deploy reports health_check_failed synchronously
• runtime log carries the app's own error line

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.

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 2026-09-21T02:23:07Z at revision 50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21): ASP.NET Core pattern fixture deployed on Ample with CANARY_FAIL=boot (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT); the same app deployed with a deliberate boot failure (CANARY_FAIL=boot): ample deploy exited 1 with a coded failure (health_check_failed when the process dies at boot, public_ingress_failed when the framework boots but every request answers 500) and the app's own error line was readable with ample logs <deployment_id> --kind runtime, so the cause is read from the framework's output rather than guessed. (expires 2027-03-20T02:23:07Z)

Last verified: 2026-09-21T02:23:07Z

Execution binding

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