networking

name	networking
description	Container networking configuration for RabbitMQ with Podman compose
license	MIT
compatibility	opencode
metadata	{"networking":"container","tool":"podman","domain":"infrastructure"}

What I Do

Provide networking configuration and troubleshooting guidance for RabbitMQ container deployment in the crypto-scout ecosystem.

Network Architecture

┌─────────────────────────────────────────────────────────────────┐
│                         Host System                              │
│                                                                  │
│  ┌──────────────────────────────────────────────────────────┐   │
│  │              crypto-scout-bridge (Network)                │   │
│  │                                                           │   │
│  │   ┌──────────────┐         ┌─────────────────────┐       │   │
│  │   │ crypto-scout │◀───────▶│  crypto-scout-      │       │   │
│  │   │     -mq      │  5672   │    client           │       │   │
│  │   │              │  5552   │                     │       │   │
│  │   └──────┬───────┘         └─────────────────────┘       │   │
│  │          │                                               │   │
│  │          │  ┌─────────────────────┐                      │   │
│  │          └──▶  crypto-scout-      │                      │   │
│  │             │    collector        │                      │   │
│  │             └─────────────────────┘                      │   │
│  │                                                           │   │
│  └──────────────────────────────────────────────────────────┘   │
│                                                                  │
│  External access: 127.0.0.1:15672 ──▶ Management UI             │
└─────────────────────────────────────────────────────────────────┘

Port Configuration

Internal Ports (Container Network Only)

Port	Protocol	Purpose	Exposure
5672	AMQP	Queue messaging	Container only
5552	Streams	Stream messaging	Container only
4369	EPMD	Erlang discovery	Container only
25672	Clustering	Inter-node communication	Container only

External Ports (Host Access)

Port	Binding	Purpose
15672	127.0.0.1:15672	Management UI (localhost only)

Network Configuration

External Network Creation

# Create once for all services using helper script
./script/network.sh

# Or manually
podman network create crypto-scout-bridge

# Verify creation
podman network ls
podman network inspect crypto-scout-bridge

Compose Network Declaration

networks:
  crypto-scout-bridge:
    name: crypto-scout-bridge
    external: true

Service Network Attachment

services:
  crypto-scout-mq:
    networks:
      - crypto-scout-bridge

DNS and Discovery

Container Hostnames

services:
  crypto-scout-mq:
    hostname: crypto_scout_mq  # Underscores for Erlang compatibility
    container_name: crypto-scout-mq

Service Discovery

Services connect using container names:

// From crypto-scout-client
Environment.builder()
    .host("crypto-scout-mq")  // Container name resolves
    .port(5552)
    .build();

Advertised Host (Streams)

# rabbitmq.conf
stream.advertised_host = crypto_scout_mq
stream.advertised_port = 5552

Connectivity Testing

From Host

# Management UI (localhost only)
curl http://127.0.0.1:15672

# AMQP/Streams NOT accessible from host
nc -zv localhost 5672  # Should fail
nc -zv localhost 5552  # Should fail

From Other Containers

# Test from client container
podman exec crypto-scout-client nc -zv crypto-scout-mq 5672
podman exec crypto-scout-client nc -zv crypto-scout-mq 5552

# Test DNS resolution
podman exec crypto-scout-client nslookup crypto-scout-mq

# Ping test
podman exec crypto-scout-client ping -c 3 crypto-scout-mq

Diagnostics

# Container network info
podman inspect crypto-scout-mq | jq '.[0].NetworkSettings.Networks'

# IP address
podman inspect -f '{{.NetworkSettings.IPAddress}}' crypto-scout-mq

# Check listening ports
podman exec crypto-scout-mq rabbitmq-diagnostics -q listeners

Troubleshooting

Connection Refused

# Check if RabbitMQ is running
podman ps | grep crypto-scout-mq
./script/rmq_compose.sh status

# Check logs for startup errors
podman logs crypto-scout-mq

# Verify port binding
podman exec crypto-scout-mq netstat -tlnp

DNS Resolution Failure

# Check network connectivity
podman exec crypto-scout-client ping crypto-scout-mq

# Verify network membership
podman inspect crypto-scout-mq | grep -A 10 "Networks"

# Restart with network
./script/rmq_compose.sh down
./script/rmq_compose.sh up -d

Port Conflicts

# Check host port usage
lsof -i :15672
lsof -i :5672
lsof -i :5552

# Change management port if needed
# In podman-compose.yml:
ports:
  - "127.0.0.1:15673:15672"

Network Not Found

# Create network if missing
./script/network.sh

# Or manually
podman network create crypto-scout-bridge

# Then restart service
./script/rmq_compose.sh restart

Advanced Configuration

Custom Subnet

# Create network with specific subnet
podman network create \
  --subnet 10.88.10.0/24 \
  --gateway 10.88.10.1 \
  crypto-scout-bridge

IPv6 Support

# podman-compose.yml
networks:
  crypto-scout-bridge:
    enable_ipv6: true
    ipam:
      config:
        - subnet: 2001:db8::/64

MTU Configuration

# If experiencing network issues
networks:
  crypto-scout-bridge:
    driver_opts:
      mtu: 1400

Security Considerations

Network Isolation

# Verify no host exposure for AMQP/Streams
podman port crypto-scout-mq
# Should only show: 127.0.0.1:15672 -> 15672

# Verify internal ports not exposed
podman inspect crypto-scout-mq | grep -A 20 PortBindings

Inter-Service Communication

• Services should use container names for DNS resolution
• No hardcoded IP addresses
• Communication encrypted at application level if needed
• All services must be on crypto-scout-bridge network

Performance Tuning

Connection Limits

ulimits:
  nofile:
    soft: 65536
    hard: 65536

Network Mode

# For host networking (not recommended for production)
network_mode: host

Monitoring

Network Metrics

# Container network I/O
podman stats crypto-scout-mq

# Connection count
podman exec crypto-scout-mq rabbitmqctl list_connections | wc -l

# Network interfaces in container
podman exec crypto-scout-mq ip addr

Bridge Network Inspection

# Inspect the bridge network
podman network inspect crypto-scout-bridge

# List containers on network
podman network inspect crypto-scout-bridge | jq '.[0].containers'

When to Use Me

Use this skill when:

• Setting up container networking
• Troubleshooting connectivity issues
• Configuring service discovery
• Understanding port exposure
• Implementing network security
• Optimizing network performance
• Debugging DNS resolution