Message Queue

The Message Queue service provides managed messaging backed by RabbitMQ (AMQP protocol) or NATS (lightweight pub/sub). The Message Queue Agent handles installation, clustering, user management, and high availability.

Engines

## Features

• HA mirrored queues — RabbitMQ queues can be mirrored across nodes for high availability
• Management UI — RabbitMQ includes a web-based management interface for monitoring
• Clustering — both engines support multi-node clusters for scalability
• TLS — encrypted connections between clients and the message broker
• User/permission management — fine-grained access control per vhost and queue

Create a Message Queue

RabbitMQ Cluster

agentmetal queue create \
  --name events \
  --engine rabbitmq \
  --nodes 3 \
  --ha

NATS Cluster

agentmetal queue create \
  --name notifications \
  --engine nats \
  --nodes 3

Manage Users (RabbitMQ)

agentmetal queue user create events \
  --username app \
  --password-from-secret app-mq-password \
  --vhost / \
  --permissions "configure=.:write=.:read=.*"

Get Connection Info

agentmetal queue get events --connection-string

Output for RabbitMQ:

amqp://app:**@events.internal:5672/

Enable HA Policies (RabbitMQ)

Configure queue mirroring:

agentmetal queue policy set events \
  --name ha-all \
  --pattern ".*" \
  --definition '{"ha-mode": "all", "ha-sync-mode": "automatic"}'

What the Agent Manages

The Message Queue Agent performs these operations:

1. Erlang + RabbitMQ installation — installs the Erlang runtime and RabbitMQ server, or installs the NATS server binary
2. Cluster joining — configures Erlang cookies for RabbitMQ clustering or NATS route configuration for cluster formation
3. User/permission management — creates vhosts, users, and permission sets for RabbitMQ
4. HA configuration — sets up mirrored queue policies for RabbitMQ, or JetStream for NATS persistence
5. TLS setup — generates and configures TLS certificates for encrypted client connections
6. Health monitoring — checks queue depths, message rates, node connectivity, and memory usage
7. Self-healing — restarts crashed nodes, re-joins partitioned cluster members, and rebalances queues

Management UI

For RabbitMQ, access the management UI:

agentmetal queue get events --management-url

The management interface provides real-time visibility into queues, exchanges, bindings, connections, and channels.