Consul vs Envoy: What are the differences?

Introduction

Consul and Envoy are two popular tools used in modern software architectures to manage service discovery, load balancing, and network infrastructure. While both serve similar purposes, they have key differences that set them apart from each other.

1. Service Mesh vs Service Discovery: Consul primarily focuses on providing service discovery and health checking capabilities. It acts as a central registry for services in a distributed system, allowing services to locate and communicate with each other. In contrast, Envoy is built with a broader service mesh architecture in mind. Along with service discovery, Envoy also offers additional features like load balancing, traffic management, and observability.

2. Protocol Support: Consul offers support for multiple service discovery mechanisms, including DNS, HTTP JSON APIs, and built-in native support for gRPC and Envoy proxy. It can be seamlessly integrated into various application protocols. On the other hand, Envoy is primarily designed as a high-performance L7 proxy and supports a wide range of protocols such as HTTP/2, gRPC, WebSocket, and MongoDB. It provides advanced features like protocol-aware routing and filtering.

3. Multitenancy and Platform Agnosticism: Consul is a standalone service discovery system that can be used in any infrastructure environment. It provides multi-tenancy support, allowing different organizations or teams to use separate namespaces within the same Consul cluster. Envoy, on the other hand, is often deployed as a sidecar proxy alongside each service instance within a service mesh architecture. This allows for more fine-grained control and observability of the traffic between services.

4. Configuration and Management: Consul offers a simple configuration model where users can define services, health checks, and associated metadata using a declarative configuration file. It provides a web UI and a powerful CLI for configuration management and monitoring. Envoy, on the other hand, supports a dynamic configuration model using an API server. It can be dynamically updated and controlled in real-time, allowing for granular control over routing and configuration without needing a restart.

5. Community and Ecosystem: Consul is developed by HashiCorp, a company known for its popular infrastructure toolset. It has a strong community support and a wide range of integrations with other HashiCorp products like Terraform. Envoy, on the other hand, was originally developed by Lyft but is now part of the Cloud Native Computing Foundation (CNCF). It has gained significant traction and has a growing ecosystem with support from various companies and organizations.

6. Observability and Security: Consul provides health checking and monitoring capabilities out-of-the-box, allowing users to check the availability and responsiveness of services. It also supports secure communication between services using TLS encryption. Envoy, on the other hand, provides more advanced observability features like distributed tracing and metrics collection. It integrates with popular observability tools like Prometheus and Jaeger. Envoy also offers advanced security features like mutual TLS authentication and rate limiting.

In summary, Consul primarily focuses on service discovery while Envoy provides a more comprehensive service mesh architecture with additional features like load balancing, traffic management, and observability. Consul is platform agnostic and supports multiple service discovery mechanisms, while Envoy is often deployed as a sidecar proxy and offers more fine-grained control over traffic. Consul has a simpler configuration model and is developed by HashiCorp, while Envoy has a more dynamic configuration model and is part of the CNCF ecosystem. Consul provides basic observability and security features, while Envoy offers more advanced observability and security capabilities.