Metadata Center on Apache Dubbo

Overview of the Metadata Center

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

The Metadata Center provides access to two types of metadata in Dubbo:

1. Address discovery metadata, used for application-level service discovery.
1. Service operation and maintenance metadata, used for peripheral operation and maintenance systems such as visualization consoles for service queries, testing, etc.

1 Address Discovery Metadata

Dubbo3 introduces the application-level service discovery mechanism to address performance issues in heterogeneous microservice systems and large-scale cluster practices. Application-level service discovery will fully replace the interface-level service discovery of version 2.x. To maintain Dubbo’s usability oriented towards services/interfaces and flexibility in service governance, Dubbo has built a metadata mechanism around application-level service discovery, specifically interface-application mapping relations and interface configuration metadata.

Nacos

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

1 Preparations

Understand Dubbo basic development steps
Refer to Nacos to start Nacos server

When Dubbo uses version 3.0.0 or higher, Nacos version 2.0.0 or higher is required.

2 Usage Instructions

The steps to integrate Dubbo with Nacos as a metadata center are very simple, mainly divided into adding Maven dependency and configuring metadata center.

If the metadata address (dubbo.metadata-report.address) is also not configured, the address of the registry will be used as the metadata center.

Zookeeper

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

1 Preparation

Understand Dubbo Basic Development Steps
Install and start Zookeeper

2 Instructions

2.1 Adding Maven Dependency

If the project has already enabled Zookeeper as the registry center, no additional configuration is needed.

If Zookeeper is not used as the registry center, please refer to Add Zookeeper-related dependencies for the registry center.

2.2 Enable Zookeeper Configuration Center

<dubbo:metadata-report address="zookeeper://127.0.0.1:2181"/>

dubbo
 metadata-report
 address: zookeeper://127.0.0.1:2181

dubbo.metadata-report.address=zookeeper://127.0.0.1:2181

MetadataReportConfig metadataConfig = new MetadataReportConfig();
metadataConfig.setAddress("zookeeper://127.0.0.1:2181");

For the format of address, please refer to zookeeper register center - Enable Configuration

More Metadata Center Extension Implementations

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

The Dubbo framework also provides default implementations for metadata center adapters such as Redis, etcd, and Consul.

Redis

The Redis implementation is provided by the core library but requires the following dependency:

<dependency>
	<dependency>
 <groupId>redis.clients</groupId>
 <artifactId>jedis</artifactId>
 <version>3.10.0</version>
 </dependency>
</dependency>

dubbo
 metadata-report
 address: redis://127.0.0.1:1111

dubbo.metadata-report.address=redis://127.0.0.1:1111

Etcd

The etcd metadata center is maintained by the community ecosystem library. For details, see .

Add the dependency:

<dependency>
 <groupId>org.apache.dubbo.extensions</groupId>
 <artifactId>dubbo-metadata-report-etcd</artifactId>
 <version>3.3.0</version>
</dependency>

Adjust the configuration: