Dubbo Core Features on Apache Dubbo

Microservices Development

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Dubbo addresses a series of challenges from development, deployment to governance and operation of enterprise microservices. Dubbo provides developers with a full set of services from project creation, development testing, to deployment, visual monitoring, traffic governance, and ecosystem integration.

Development: Dubbo offers implementations in Java, Go, Rust, Node.js, and defines a microservices development paradigm. The accompanying scaffolding can be used to quickly create microservice project skeletons.
Deployment: Dubbo applications support deployment on virtual machines, Docker containers, Kubernetes, and service mesh architectures.
Service Governance: Dubbo provides governance capabilities such as address discovery, load balancing, and traffic control. The official Admin visual console and rich microservice ecosystem integration are also provided.

Development

Next, we will explain the basic steps of Dubbo application development using a Java-based Spring Boot project as an example. The entire process is very intuitive and simple, and the development process for other languages is similar.

Service Discovery

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Dubbo provides a Client-Based service discovery mechanism that relies on third-party registry center components to coordinate the service discovery process. It supports common registry centers such as Nacos, Consul, Zookeeper, etc.

Below is a basic working principle diagram of Dubbo’s service discovery mechanism:

Service discovery involves three roles: provider, consumer, and registry center. Dubbo provider instances register URL addresses to the registry center, which aggregates the data. Dubbo consumers read the address list from the registry center and subscribe to changes. Whenever the address list changes, the registry center notifies all subscribed consumer instances with the latest list.

Load Balancing

Mon, 01 Jan 0001 00:00:00 +0000

When it comes to cluster load balancing, Dubbo provides multiple balancing strategies, with the default being weighted random, a weighted random load balancing strategy.

In terms of implementation, Dubbo provides client-side load balancing, meaning the Consumer determines which Provider instance to submit the request to using a load balancing algorithm.

Load Balancing Strategies

Currently, Dubbo has the following built-in load balancing algorithms, which can be enabled by adjusting configuration items.

Communication Protocols

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The Dubbo framework provides a custom high-performance RPC communication protocol: the Triple protocol based on HTTP/2 and the Dubbo2 protocol based on TCP. In addition, the Dubbo framework supports any third-party communication protocol, such as the officially supported gRPC, Thrift, REST, JsonRPC, Hessian2, etc. More protocols can be implemented through custom extensions. This is very useful for multi-protocol communication scenarios often encountered in microservice practices.

The Dubbo framework does not bind to any communication protocol. In implementation, Dubbo’s support for multiple protocols is very flexible. It allows you to publish multiple services using different protocols within one application and supports publishing all protocols externally using the same port.

Extension Adaptation

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Dubbo is designed to be highly extensible. Through these extension points, you can:

Intercept traffic and control traffic behavior
Optimize some of Dubbo’s default strategies and implementations as needed
Adapt Dubbo services to internal microservice clusters or other mainstream open-source components

Everything is Extensible

Dubbo’s extensibility allows the Dubbo project to be conveniently divided into sub-modules, achieving hot-plug features. Users can completely replace Dubbo’s native implementations based on their own needs to meet their business requirements.

Observability Service

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Dubbo internally maintains multiple dimensions of observable metrics and supports various ways of visual monitoring. Observable metrics are generally divided into three measurement dimensions:

Admin The Admin console visually displays applications, services, instances, and dependencies in the cluster. It supports the issuance of traffic governance rules and provides tools such as service testing, mock, and document management to improve R&D testing efficiency.
Metrics Dubbo collects a series of traffic metrics such as QPS, RT, number of successful requests, number of failed requests, etc., as well as a series of internal component statuses such as thread pool count, service health status, etc.

Authentication and Authorization

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Dubbo provides a comprehensive mechanism for building a secure microservice communication system (zero-trust system), which includes:

Avoiding man-in-the-middle attacks during communication, Dubbo provides identity authentication and TLS-based communication link encryption capabilities.
Controlling inter-service access authorization, Dubbo provides mTLS and permission check mechanisms.

Through this document, you will learn how to use Dubbo’s security mechanisms to build a zero-trust microservice system, achieving identity authentication, transparent link encryption, authorization, auditing, and other capabilities. Since building zero trust is a systematic task and Dubbo is only a part of the data communication layer, you may need a series of infrastructure support, including certificate generation, distribution, and security policy management.

Service Mesh

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Dubbo Mesh is Dubbo’s comprehensive microservice solution in the context of cloud-native, helping developers integrate Dubbo services with the standard Kubernetes Native Service system, allowing Dubbo applications to seamlessly integrate with mainstream service mesh products like Istio.

Below is the deployment architecture diagram of Dubbo Mesh

Control Plane. Istio serves as the unified control plane, providing capabilities such as Kubernetes adaptation, service discovery, certificate management, observability, and traffic governance for the cluster.
Data Plane. Dubbo application instances act as data plane components, supporting two deployment modes:
- Proxy Mode. The Dubbo process and Envoy are deployed in the same pod, with all traffic to and from Dubbo intercepted by the Envoy proxy, which performs traffic control.
- Proxyless Mode. The Dubbo process is deployed independently, with direct communication between processes, interacting directly with the control plane via the xDS protocol.

For more information on service mesh architecture and why to integrate with the Istio control plane, please refer to the Istio official website. This document does not cover these general topics but focuses on the Dubbo Mesh solution itself.

Microservices Ecosystem

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The Dubbo community, along with many excellent open-source projects, has established a rich microservices ecosystem around Dubbo. This ensures that developers do not need to worry about subsequent service governance demands from the first day they choose Dubbo as their development framework. Dubbo provides production-grade solutions for every common issue.

The following table shows the support status of ecosystem components based on the latest Dubbo Java 3.2.x version. It will be continuously updated according to development progress. The completeness of components supported by each language may vary, so please refer to the detailed descriptions in each language reference manual.

More Advanced Features

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As a microservices framework closely related to application development and aimed at providing enterprise-level service governance capabilities for microservice clusters, Dubbo also offers many advanced features, covering service invocation behavior control, service diagnosis and tuning, service governance, and more.

There may be slight differences in feature implementation and configuration methods across different language SDKs. For specific feature lists and usage, please refer to the following documents:

Java
Golang

Controlling Service Invocation Behavior

Service Versioning
Service Grouping
Group Aggregation
Asynchronous Invocation
Asynchronous Execution
Streaming Communication
Reactive Programming
Generic Invocation
Generic Implementation
Implicit Parameter Passing in Invocation Chain
RPC Invocation Context
Invocation Trigger Event Notification
Server Callback to Client
Subscribe Only
Register Only
Dynamically Specify IP for Invocation at Runtime
Direct Connection to Provider
Startup Check
Local Invocation
Parameter Validation
Local Mock
Local Stub
Echo Test
Invocation Information Logging
Delayed Exposure
Cluster Fault Tolerance
Service Degradation

Diagnosis and Tuning

Port Protocol Multiplexing
Thread Pool Isolation
Multiple Protocols
Multiple Registries
Request Time Sampling
Thread Model
Service Reference Configuration Object Caching
Route Status Collection
Load Balancing
Simplified Registration Information
Invocation Result Caching
Concurrency Control
Connection Control
Delayed Connection
Sticky Connection
Graal VM Support
Export Thread Stack
Kryo and FST Serialization
Custom Service Container
Graceful Shutdown
Custom Host Address Exposure
Consistent Hashing Addressing
Log Framework Adaptation and Runtime Management
Kubernetes Lifecycle Probes