CybusMQ

The Industrial MQTT Broker.

CybusMQ is a robust MQTT broker tailored for industrial applications, offering support for both MQTT 5 and MQTT 3.1.1 protocols. It serves as the central message broker within the Connectware ecosystem, facilitating efficient data exchange and inter-service communication.

Key Features

• Industrial-grade stability and scalability: Engineered to withstand the demands of industrial environments, ensuring reliable performance under high-load conditions. See Scaling the Broker Cluster for scaling strategies.

• Protocol support: Offers services for MQTT, secure MQTT over TLS (MQTTS), and MQTT over WebSockets, providing flexibility in communication methods. See Collocated One-way and Mutual TLS for TLS configuration details.

• Metrics exposure: Exposes comprehensive usage and performance metrics for integration with monitoring systems like Prometheus and Grafana. See Monitoring & Analytics for details.

• Authentication delegation: Employs webhooks to delegate authentication processes to the Auth-Server, ensuring secure access control. See Self-Refreshing Webhooks Cache for implementation details.

Technical Specifications

• Foundation: CybusMQ is built on VerneMQ, a high-performance distributed MQTT message broker. This foundation provides robust messaging capabilities across distributed systems.

• Technology stack: CybusMQ is written in Erlang, a language optimized for concurrent operations and fault tolerance. The Erlang/OTP virtual machine uses preemptive scheduling, delivering consistent low latency for real-time applications at scale.

• Configuration: CybusMQ can be configured through environment variables and configuration files. See Configuration Options and Environment Variables for available settings.

For a detailed comparison between CybusMQ and VerneMQ, see Feature Overview.

Feature Overview

Comparison between CybusMQ and VerneMQ, highlighting the advantages of CybusMQ.

Feature	CybusMQ	VerneMQ	CybusMQ Advantage
Performance & Scalability
Message Deduplication for Overlapping Subscriptions	Configurable single/multiple delivery	Multiple delivery	Reduced network overhead and simplified client implementation
Synchronous SUBSCRIBE Handling	Synchronous processing at cluster level	Asynchronous processing	Better control over subscription acknowledgments
Clustering & High Availability
Continuous Cluster Discovery in Kubernetes	Periodic discovery attempts at runtime	Single cluster discovery attempt at startup	Seamless scaling and node management in cloud environments
Clustering Connection Improvements	Detached queue and sender tolerating network instabilities, multithreaded routing on receive	Single sender/queue sensitive to network delays, single-threaded routing on receive	Better cluster stability and performance
Metadata Store Improvements	Improved data structures, optimizations, faster initial sync	Upscale is slow and memory-intensive for aged replicas	Faster initial sync when cluster is upscaled, better memory profile
Security
Collocated One-way and Mutual TLS	Flexible TLS configuration options	Separate listeners needed for one-way and mutual TLS	Simplified client configuration and network maintenance
Self-Refreshing Webhooks Cache	Detached authentication updates from publish processing	Trial and error expiration strategy during publish processing	No delayed message forwarding due to authentication