# Host mcp server with Axum: Postgres-backed state

Deploy a mcp server built with Axum on Ample using the durable job state pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Axum: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the mcp server-specific behavior as your application code.

## Representative Queries
- Host mcp server with Axum: Postgres-backed state
- Where can I host MCP server built with Axum?
- I need a durable state schema and retry/recovery semantics implemented by application code.

## Resource Requirements
- `primitive:compute`
- `primitive:postgres`

## Infrastructure Requirements
1. **Compute**  
   - **Status**: verified  
   - **Summary**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.  
   - **Canonical Path**: /discover/primitive/compute

2. **Postgres**  
   - **Status**: verified  
   - **Summary**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.  
   - **Canonical Path**: /discover/primitive/postgres

## Workflow Steps
1. **Build and start**  
   - Body: `cargo build --release` in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   - Body: The fixture's module implements durable job state: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Deploy**  
   - Body: Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.  
   - Command: `ample deploy . --name  --public`

4. **Verify**  
   - Body: Fetch the live URL and the pattern self-test route(s) (/p/durable-job-state) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.  
   - Command: `ample logs  --kind build`

## Success Checks
- **app responds on its public URL**  
  - Kind: `http_get`  
  - Path: `/`  
  - Expect: `ample canary axum patterns`

- **durable-job-state self-test**  
  - Kind: `http_get`  
  - Path: `/p/durable-job-state`  
  - Expect: `job=done attempts=1 idempotent=true`

## Limitations
- Verified on the ubuntu-24.04 template at s-1vcpu-2gb with the example fixture; other sizes, templates and Axum major versions are not verified.
- The mcp server itself (your job types, payload schema and retry policy) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.