## Host mcp server with Spring Boot: Postgres-backed state

Deploy a mcp server built with Spring Boot 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 Spring Boot: 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 Spring Boot: Postgres-backed state
- Where can I host MCP server built with Spring Boot?
- I need a durable state schema and retry/recovery semantics implemented by application code.

### Prerequisites
- A Spring Boot project that builds and starts with the documented commands (./mvnw -q -DskipTests package or the Gradle wrapper) producing one application jar, then java -jar on the jvm-21 template (Temurin JDK 21) with server.port read from PORT.
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
- An Ample account token with servers:write, databases:read.

### Workflow Steps
1. **Build and start**  
   `./mvnw -q -DskipTests package` (or the Gradle wrapper) producing one application jar, then `java -jar` on the jvm-21 template (Temurin JDK 21) with server.port read from PORT. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   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**  
   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.  
   `ample deploy . --name --public`

4. **Verify**  
   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`.  
   `ample logs --kind build`

### Success Checks
- App responds on its public URL
- Durable-job-state self-test

### Limitations
- Verified on the jvm-21 template at s-1vcpu-2gb with the example fixture; other sizes, templates, and Spring Boot 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.

### Cost Estimate
- Currency: USD
- Monthly Amount: 10.0
- Basis: size prices from pricing.toml

Components:
- App server: Size: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: 5.0
- Managed PostgreSQL database: Size: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: 5.0

### Evidence Summary
- **Canary Run**: Spring Boot pattern fixture deployed on Ample...

### Formats
- [HTML Format](/content/recipes/mcp-server/spring-boot/persistent-state/index.html)
- [Markdown Format](/content/recipes/mcp-server/spring-boot/persistent-state.md)
- [JSON Format](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Amcp-server%3Aspring-boot%3Apersistent-state)