Host mcp server with Spring Boot: worker execution and job state

Summary

Deploy a mcp server built with Spring Boot as a public web service plus a dedicated worker process on Ample. ample plan --write discovers both services and their shared database and writes ample.toml; ample up reconciles the topology: a managed PostgreSQL 16 database, a public web microVM and a private worker microVM (kind worker, no public URL), both reading DATABASE_URL. Verified on Spring Boot: a separately deployed worker service (kind worker, no public URL) sharing a declared managed PostgreSQL database with the web service, consuming a jobs table with row locks and marking jobs done once (worker=done attempts=1). Not separately tested: your job payloads, retry policy and scheduling; treat the mcp server-specific behavior as your application code.

Infrastructure requirements

• Verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
• 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

• A repository with the web app and the worker as separate service directories (the fixture uses apps/web and apps/worker), each building and starting 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; the worker starts with java -jar of its own Maven module (plain JDBC) and binds no port)
• Both services read DATABASE_URL at runtime and share one jobs table; the worker claims rows with SELECT ... FOR UPDATE SKIP LOCKED and marks them done once
• An Ample account token with servers:write and databases:write (ample up creates the database)

Exact tested configuration

• template: jvm-21
• runtime: java
• size: s-1vcpu-2gb
• build: ./mvnw -q -DskipTests package
• start: java -jar $(ls target/*.jar | grep -v -- '-plain' | head -n 1)

Steps

1. Plan the topology. Run the planner once. It discovers the web and worker services, infers kind = "worker" for the process without a port, declares the database each service needs, and writes ample.toml. Exit 2 means it left questions in the manifest; answer them with --answer or by editing the file.

   ample plan --write .

2. Share one database. Keep a single [databases.main] with engine = "postgres", drop any per-service database the planner added, and set DATABASE_URL = { database = "main" } under both [services.web.env] and [services.worker.env].

   ample plan --offline .

3. Apply. Reconcile the whole manifest in dependency order: the database first, then both services. It is idempotent and never destructive; exit 0 means everything applied, 2 needs input, 1 a failed resource (independent siblings still proceed and re-running resumes).

   ample up .

4. Verify. Fetch the web service URL and its worker status route (/p/worker-queue/status in the example) and confirm the worker processed the enqueued job; on failure read the worker service's runtime logs.

   ample logs <deployment_id> --kind runtime

Tested examples

• Spring Boot web + worker fixture (tests/deploy-canaries/spring-boot-worker): A Spring Boot web app (apps/web) and a worker process (apps/worker) sharing one managed PostgreSQL database; the queue module is under tests/deploy-canaries/_pattern-modules.

Success checks

• web service responds on its public URL (/ on the live URL, expect ample canary spring boot patterns)
• worker consumed the enqueued job (/p/worker-queue/status on the live URL, expect worker=done attempts=1 result=processed-by-worker)

Limitations

• Verified on the jvm-21 template at s-1vcpu-2gb for both services with the example fixture; other sizes, templates and Spring Boot major versions are not verified.
• The mcp server itself (your job payloads, retry policy and scheduling) is application code and was not separately tested; the worker-queue check is what was verified.
• The worker is a single long-running process supervised in its own microVM; there is no scheduler, cron or horizontal worker scaling in this recipe, and the check ran immediately after deploy so idle behavior of the worker VM is not verified.
• The worker service is private: it has no public URL and is reached only through the shared database; both services are placed with their database.
• Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.
• Region, compliance attestations and request-duration limits are unknown and not claimed.

Cost estimate

Estimated 15.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

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

Always-on monthly price of the tested sizes for the web service, the worker service and the database; apps auto-pause when idle.

Verification evidence

• canary_run on 2026-09-20T22:41:46Z at revision af6f45adea26-dirty (CLI af6f45a): Spring Boot web service plus a separate Spring Boot worker process deployed on Ample with ample plan --write then ample up (./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 web service enqueued a job that the private worker service consumed from the shared managed PostgreSQL database. Pattern proof: a separately deployed worker service (kind worker, no public URL) sharing a declared managed PostgreSQL database with the web service, consuming a jobs table with row locks and marking jobs done once (worker=done attempts=1). (expires 2027-03-19T22:41:46Z)

Last verified: 2026-09-20T22:41:46Z

Execution binding

MCP tool ample_up (registry mcp:ample_up), schema hash db7ca0facfe2cd28 observed 2026-09-21T03:19:59.525781+00:00 at revision 49962bcade4f, binding state current, required scopes: servers:write, databases:write.

Input schema

{
  "additionalProperties": false,
  "properties": {
    "path": {
      "description": "Directory containing ample.toml (the whole topology is applied)",
      "maxLength": 512,
      "minLength": 1,
      "type": "string"
    },
    "wait_secs": {
      "description": "Maximum seconds to wait for each service deployment",
      "maximum": 3600,
      "minimum": 30,
      "type": "integer"
    }
  },
  "required": [
    "path"
  ],
  "type": "object"
}

Next actions

• Browse the catalog index (GET /v1/catalog on the api origin; auth: false, approval: false)
• Search published recipes by intent, stack and constraints (POST /v1/catalog/search on the api origin; auth: false, approval: false)
• Prepare a side-effect-free deployment plan for an authorized project (POST /v1/catalog/plan on the api origin; auth: true, approval: false)
• Read the existing agent authentication setup (GET /mcp/setup on the api origin; auth: false, approval: false)
• Browse MCP server (GET /v1/catalog/nodes/workload%3Amcp-server on the api origin; auth: false, approval: false)
• Browse Spring Boot (GET /v1/catalog/nodes/stack%3Aframework-spring-boot on the api origin; auth: false, approval: false)
• Browse Dedicated worker process (GET /v1/catalog/nodes/pattern%3Adedicated-worker-process on the api origin; auth: false, approval: false)
• Browse Deploy MCP server (GET /v1/catalog/nodes/intent%3Adeploy-mcp-server on the api origin; auth: false, approval: false)

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