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<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Apache Dubbo – 元数据中心</title><link>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/</link><description>Recent content in 元数据中心 on Apache Dubbo</description><generator>Hugo -- gohugo.io</generator><language>zh-cn</language><atom:link href="https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/index.xml" rel="self" type="application/rss+xml"/><item><title>Overview: 元数据中心概述</title><link>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/overview/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/overview/</guid><description>
&lt;p>元数据中心为 Dubbo 中的两类元数据提供了存取能力&lt;/p>
&lt;ul>
&lt;li>1 地址发现元数据&lt;/li>
&lt;li>2 服务运维元数据&lt;/li>
&lt;/ul>
&lt;h2 id="1-地址发现元数据">1 地址发现元数据&lt;/h2>
&lt;p>Dubbo3 中引入了 &lt;a href="https://dubbo.apache.org/zh-cn/overview/core-features/service-discovery/#%E9%9D%A2%E5%90%91%E7%99%BE%E4%B8%87%E5%AE%9E%E4%BE%8B%E9%9B%86%E7%BE%A4%E7%9A%84%E6%9C%8D%E5%8A%A1%E5%8F%91%E7%8E%B0%E6%9C%BA%E5%88%B6">应用级服务发现机制&lt;/a> 用来解决异构微服务体系互通与大规模集群实践的性能问题，应用级服务发现将全面取代 2.x 时代的接口级服务发现。
同时为了保持 Dubbo 面向服务/接口的易用性、服务治理的灵活性，Dubbo 围绕应用级服务发现构建了一套元数据机制，即 &lt;code>接口 - 应用映射关系&lt;/code> 与 &lt;code>接口配置元数据&lt;/code>。&lt;/p>
&lt;h3 id="11-接口---应用映射关系">1.1 接口 - 应用映射关系&lt;/h3>
&lt;p>Dubbo 一直以来都能做到精确的地址发现，即只订阅 Consumer 声明要关心的服务及相关的地址列表，相比于拉取/订阅全量地址列表，这样做有很好的性能优势。
在应用级服务发现模型中，想做到精确地址订阅并不容易，因为 Dubbo Consumer 只声明了要消费的接口列表，Consumer 需要能够将接口转换为 Provider 应用名才能进行精准服务订阅，&lt;/p>
&lt;p>为此，Dubbo 需要在元数据中心维护这一份 &lt;code>接口名-&amp;gt;应用名&lt;/code> 的对应关系，Dubbo3 中通过 provider 启动的时候主动向元数据中心上报实现。
接口 (service name) - 应用 (Provider application name) 的映射关系可以是一对多的，即一个 service name 可能会对应多个不同的 application name。&lt;/p>
&lt;p>以 zookeeper 为例，映射关系保存在以下位置:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>$ ./zkCli.sh
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>$ get /dubbo/mapping/org.apache.dubbo.demo.DemoService
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>$ demo-provider,two-demo-provider,dubbo-demo-annotation-provider
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;em>① 节点路径是 &lt;code>/dubbo/mapping/{interface name}&lt;/code>&lt;/em>&lt;/p>
&lt;p>&lt;em>② 多个应用名通过英文逗号 &lt;code>,&lt;/code> 隔开&lt;/em>&lt;/p>
&lt;h3 id="12-接口配置元数据">1.2 接口配置元数据&lt;/h3>
&lt;p>&lt;code>接口级配置元数据&lt;/code>是作为地址发现的补充，相比于 Spring Cloud 等地址发现模型只能同步 ip、port 信息，Dubbo 的服务发现机制可以同步接口列表、接口定义、接口级参数配置等信息。
这部分内容根据当前应用的自身信息、以及接口信息计算而来，并且从性能角度出发，还根据元数据生成 revision，以实现不同机器实例间的元数据聚合。&lt;/p>
&lt;p>以 Zookeeper 为例，接口配置元数据保存在以下位置，如果多个实例生成的 revision 相同，则最终会共享同一份元数据配置：&lt;/p>
&lt;p>&lt;code>/dubbo/metadata/{application name}/{revision}&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">[&lt;/span>zk: localhost:2181&lt;span style="color:#719e07">(&lt;/span>CONNECTED&lt;span style="color:#719e07">)&lt;/span> 33&lt;span style="color:#719e07">]&lt;/span> get /dubbo/metadata/demo-provider/da3be833baa2088c5f6776fb7ab1a436
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-json" data-lang="json">&lt;span style="display:flex;">&lt;span>{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;app&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;revision&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;da3be833baa2088c5f6776fb7ab1a436&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;services&amp;#34;&lt;/span>:{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;org.apache.dubbo.demo.DemoService:dubbo&amp;#34;&lt;/span>:{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;protocol&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;path&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;params&amp;#34;&lt;/span>:{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHello,sayHelloAsync&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;deprecated&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;pid&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;38298&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;service-name-mapping&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;timeout&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;3000&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;generic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;delay&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dynamic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;REGISTRY_CLUSTER&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;registry1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;anyhost&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;timestamp&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1626887121829&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> },
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;org.apache.dubbo.demo.RestDemoService:1.0.0:rest&amp;#34;&lt;/span>:{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;version&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;protocol&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;rest&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;path&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;params&amp;#34;&lt;/span>:{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;getRemoteApplicationName,sayHello,hello,error&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;deprecated&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;pid&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;38298&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;service-name-mapping&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;version&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;timeout&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;generic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;revision&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;delay&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dynamic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;REGISTRY_CLUSTER&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;registry1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;anyhost&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;timestamp&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1626887120943&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h2 id="2-服务运维元数据">2 服务运维元数据&lt;/h2>
&lt;p>Dubbo 上报的服务运维元数据通常为各种运维系统所用，如服务测试、网关数据映射、服务静态依赖关系分析等。&lt;/p>
&lt;p>各种第三方系统可直接读取并使用这部分数据，具体对接方式可参见本章提及的几个第三方系统。&lt;/p>
&lt;h3 id="21-provider-上报的元数据">2.1 Provider 上报的元数据&lt;/h3>
&lt;p>provider端存储的元数据内容如下：&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-json" data-lang="json">&lt;span style="display:flex;">&lt;span>{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;parameters&amp;#34;&lt;/span>: {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;side&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;methods&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;sayHello&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dubbo&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;threads&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;100&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;interface&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.samples.metadatareport.configcenter.api.AnnotationService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;threadpool&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;fixed&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;version&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;1.1.1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;generic&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;revision&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;1.1.1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;valid&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;application&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;metadatareport-configcenter-provider&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;default.timeout&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;group&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;d-test&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;anyhost&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> },
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;canonicalName&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.samples.metadatareport.configcenter.api.AnnotationService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;codeSource&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;file:/Users/cvictory/workspace/work-mw/dubbo-samples/dubbo-samples-metadata-report/dubbo-samples-metadata-report-configcenter/target/classes/&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;methods&amp;#34;&lt;/span>: [{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;name&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;sayHello&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;parameterTypes&amp;#34;&lt;/span>: [&lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>],
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;returnType&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }],
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;types&amp;#34;&lt;/span>: [{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;type&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;properties&amp;#34;&lt;/span>: {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;value&amp;#34;&lt;/span>: {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;type&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;char[]&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> },
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;hash&amp;#34;&lt;/span>: {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;type&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;int&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }, {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;type&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;int&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }, {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;type&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;char&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }]
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;em>① &lt;code>parameters&lt;/code> 为服务配置与参数详情。&lt;/em>&lt;/p>
&lt;p>&lt;em>② &lt;code>types&lt;/code> 为服务定义信息。&lt;/em>&lt;/p>
&lt;h5 id="consumer-上报的元数据">Consumer 上报的元数据：&lt;/h5>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-json" data-lang="json">&lt;span style="display:flex;">&lt;span>{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;valid&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;side&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;consumer&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;application&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;metadatareport-configcenter-consumer&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;methods&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;sayHello&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;default.timeout&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;6666&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;dubbo&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;interface&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.samples.metadatareport.configcenter.api.AnnotationService&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;version&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;1.1.1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;revision&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;1.1.1&amp;#34;&lt;/span>,
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;#34;group&amp;#34;&lt;/span>: &lt;span style="color:#2aa198">&amp;#34;d-test&amp;#34;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;em>Consumer 进程订阅时使用的配置元数据。&lt;/em>&lt;/p>
&lt;h2 id="3-元数据上报工作机制">3 元数据上报工作机制&lt;/h2>
&lt;p>元数据上报默认是一个异步的过程，为了更好的控制异步行为，元数据配置组件 (metadata-report) 开放了两个配置项：&lt;/p>
&lt;ul>
&lt;li>失败重试&lt;/li>
&lt;li>每天定时重试刷新&lt;/li>
&lt;/ul>
&lt;h3 id="31-retrytimes-失败重试">3.1 retrytimes 失败重试&lt;/h3>
&lt;p>失败重试可以通过 retrytimes （重试次数。默认 100），retryperiod（重试周期。默认 3000ms）进行设置。&lt;/p>
&lt;h3 id="32-定时刷新">3.2 定时刷新&lt;/h3>
&lt;p>默认开启，可以通过设置 cycleReport=false 进行关闭。&lt;/p>
&lt;h3 id="33-完整的配置项">3.3 完整的配置项&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.address&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">zookeeper://127.0.0.1:2181&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.username&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">xxx ##非必须&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.password&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">xxx ##非必须&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.retry-times&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">30 ##非必须,default值100&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.retry-period&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">5000 ##非必须,default值3000&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.cycle-report&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">false ##非必须,default值true&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.sync.report&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">false ##非必须,default值为false&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;blockquote>
&lt;p>如果元数据地址(dubbo.metadata-report.address)也不进行配置，会判断注册中心的协议是否支持元数据中心，如果支持，会使用注册中心的地址来用作元数据中心。&lt;/p>
&lt;/blockquote>
&lt;p>请参见 &lt;a href="../../spi/description/metadata-report/">metadata-report&lt;/a> 了解如何扩展自定义第三方实现。&lt;/p></description></item><item><title>Overview: Nacos</title><link>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/nacos/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/nacos/</guid><description>
&lt;h2 id="1-预备工作">1 预备工作&lt;/h2>
&lt;ul>
&lt;li>了解 &lt;a href="https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/quick-start/spring-boot/">Dubbo 基本开发步骤&lt;/a>&lt;/li>
&lt;li>参考 &lt;a href="https://nacos.io/zh-cn/docs/quick-start.html">Nacos快速入门&lt;/a> 启动 Nacos server&lt;/li>
&lt;/ul>
&lt;blockquote>
&lt;p>当Dubbo使用&lt;code>3.0.0&lt;/code>及以上版本时，需要使用Nacos &lt;code>2.0.0&lt;/code>及以上版本&lt;/p>
&lt;/blockquote>
&lt;h2 id="2-使用说明">2 使用说明&lt;/h2>
&lt;p>Dubbo 融合 Nacos 成为元数据中心的操作步骤非常简单，大致分为 &lt;code>增加 Maven 依赖&lt;/code> 以及 &lt;code>配置元数据中心&lt;/code> 两步。&lt;/p>
&lt;blockquote>
&lt;p>如果元数据地址(dubbo.metadata-report.address)也不进行配置，会使用注册中心的地址来用作元数据中心。&lt;/p>
&lt;/blockquote>
&lt;h3 id="21-增加-maven-依赖">2.1 增加 Maven 依赖&lt;/h3>
&lt;p>如果项目已经启用 Nacos 作为注册中心，则无需增加任何额外配置。&lt;/p>
&lt;p>如果未启用 Nacos 注册中心，则请参考 &lt;a href="../../registry/nacos/#21-%E5%A2%9E%E5%8A%A0%E4%BE%9D%E8%B5%96">为注册中心增加 Nacos 依赖&lt;/a>。&lt;/p>
&lt;h3 id="22-启用-nacos-配置中心">2.2 启用 Nacos 配置中心&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:metadata-report&lt;/span> address=&lt;span style="color:#2aa198">&amp;#34;nacos://127.0.0.1:8848&amp;#34;&lt;/span>&lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-yaml" data-lang="yaml">&lt;span style="display:flex;">&lt;span>dubbo
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> metadata-report
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">address&lt;/span>: nacos://127.0.0.1:8848
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.address&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">nacos://127.0.0.1:8848&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>MetadataReportConfig metadataConfig &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> MetadataReportConfig();
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>metadataConfig.setAddress(&lt;span style="color:#2aa198">&amp;#34;nacos://127.0.0.1:8848&amp;#34;&lt;/span>);
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;code>address&lt;/code> 格式请参考 &lt;a href="../../registry/nacos/#22-%E9%85%8D%E7%BD%AE%E5%B9%B6%E5%90%AF%E7%94%A8-nacos">Nacos 注册中心 - 启用配置&lt;/a>&lt;/p>
&lt;h2 id="3-高级配置">3 高级配置&lt;/h2>
&lt;p>完整配置参数请参考 &lt;a href="../../config/properties/#metadata-report-config">metadata-report-config&lt;/a>。&lt;/p>
&lt;h2 id="4-工作原理">4 工作原理&lt;/h2>
&lt;h3 id="41-服务运维元数据overview2-服务运维元数据">4.1 &lt;a href="../overview/#2-%E6%9C%8D%E5%8A%A1%E8%BF%90%E7%BB%B4%E5%85%83%E6%95%B0%E6%8D%AE">服务运维元数据&lt;/a>&lt;/h3>
&lt;p>在 Nacos 的控制台上可看到服务提供者、消费者注册的服务运维相关的元数据信息：&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/blog/dubbo-metadata-nacos-1.png" alt="image-dubbo-metadata-nacos-1.png">&lt;/p>
&lt;p>在 Nacos 中，本身就存在配置中心这个概念，正好用于元数据存储。在配置中心的场景下，存在命名空间- namespace 的概念，在 namespace 之下，还存在 group 概念。即通过 namespace 和 group 以及 dataId 去定位一个配置项，在不指定 namespace 的情况下，默认使用 &lt;code>public&lt;/code> 作为默认的命名空间。&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>Provider&lt;span style="color:#719e07">:&lt;/span> &lt;span style="color:#2aa198">namespace: &amp;#39;public&amp;#39;, dataId: &amp;#39;{service name}:{version}:{group}:provider:{application name}&amp;#39;, group: &amp;#39;dubbo&amp;#39;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Consumer&lt;span style="color:#719e07">:&lt;/span> &lt;span style="color:#2aa198">namespace: &amp;#39;public&amp;#39;, dataId: &amp;#39;{service name}:{version}:{group}:consumer:{application name}&amp;#39;, group: &amp;#39;dubbo&amp;#39;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>当 version 或者 group 不存在时&lt;code>:&lt;/code> 依然保留:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>Provider&lt;span style="color:#719e07">:&lt;/span> &lt;span style="color:#2aa198">namespace: &amp;#39;public&amp;#39;, dataId: &amp;#39;{service name}:::provider:{application name}&amp;#39;, group: &amp;#39;dubbo&amp;#39;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Consumer&lt;span style="color:#719e07">:&lt;/span> &lt;span style="color:#2aa198">namespace: &amp;#39;public&amp;#39;, dataId: &amp;#39;{service name}:::consumer:{application name}&amp;#39;, group: &amp;#39;dubbo&amp;#39;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Providers接口元数据详情 (通过 &lt;code>report-definition=true&lt;/code> 控制此部分数据是否需要上报)：&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/blog/dubbo-metadata-nacos-3.png" alt="image-dubbo-metadata-nacos-3.png">&lt;/p>
&lt;p>Consumers接口元信息详情（通过 &lt;code>report-consumer-definition=true&lt;/code> 控制是否上报，默认 false）：&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/blog/dubbo-metadata-nacos-4.png" alt="image-dubbo-metadata-nacos-4.png">&lt;/p>
&lt;h3 id="42-地址发现---接口-应用映射overview11-接口---应用映射关系">4.2 &lt;a href="../overview//#11-%E6%8E%A5%E5%8F%A3---%E5%BA%94%E7%94%A8%E6%98%A0%E5%B0%84%E5%85%B3%E7%B3%BB">地址发现 - 接口-应用映射&lt;/a>&lt;/h3>
&lt;p>在上面提到，service name 和 application name 可能是一对多的，在 nacos 中，使用单个 key-value 进行保存，多个 application name 通过英文逗号&lt;code>,&lt;/code>隔开。由于是单个 key-value 去保存数据，在多客户端的情况下可能会存在并发覆盖的问题。因此，我们使用 nacos 中 publishConfigCas 的能力去解决该问题。在 nacos 中，使用 publishConfigCas 会让用户传递一个参数 casMd5，该值的含义是之前配置内容的 md5 值。不同客户端在更新之前，先去查一次 nacos 的 content 的值，计算出 md5 值，当作本地凭证。在更新时，把凭证 md5 传到服务端比对 md5 值, 如果不一致说明在此期间被其他客户端修改过，重新获取凭证再进行重试(CAS)。目前如果重试6次都失败的话，放弃本次更新映射行为。&lt;/p>
&lt;p>Nacos api:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>ConfigService configService &lt;span style="color:#719e07">=&lt;/span> ...
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>configService.publishConfigCas(key, group, content, ticket);
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>映射信息位于 namespace: &amp;lsquo;public&amp;rsquo;, dataId: &amp;lsquo;{service name}&amp;rsquo;, group: &amp;lsquo;mapping&amp;rsquo;.&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/user/nacos-metadata-report-service-name-mapping.png" alt="nacos-metadata-report-service-name-mapping.png">&lt;/p>
&lt;h3 id="43-地址发现---接口配置元数据overview12-接口配置元数据">4.3 &lt;a href="../overview/#12-%E6%8E%A5%E5%8F%A3%E9%85%8D%E7%BD%AE%E5%85%83%E6%95%B0%E6%8D%AE">地址发现 - 接口配置元数据&lt;/a>&lt;/h3>
&lt;p>要开启远程接口配置元数据注册，需在应用中增加以下配置，因为默认情况下 Dubbo3 应用级服务发现会启用服务自省模式，并不会注册数据到元数据中心。&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span> dubbo.application.metadata-type&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">remote&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者，在自省模式下仍开启中心化元数据注册&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>dubbo.application.metadata-type&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">local&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.report-metadata&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">true&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Nacos server 中的元数据信息详情如下：&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/blog/dubbo-metadata-nacos-2.png" alt="image-dubbo-metadata-nacos-2.png">&lt;/p></description></item><item><title>Overview: Zookeeper</title><link>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/zookeeper/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/zookeeper/</guid><description>
&lt;h2 id="1-预备工作">1 预备工作&lt;/h2>
&lt;ul>
&lt;li>了解 &lt;a href="https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/quick-start/spring-boot/">Dubbo 基本开发步骤&lt;/a>&lt;/li>
&lt;li>安装并启动 &lt;a href="https://zookeeper.apache.org/">Zookeeper&lt;/a>&lt;/li>
&lt;/ul>
&lt;h2 id="2-使用说明">2 使用说明&lt;/h2>
&lt;h3 id="21-增加-maven-依赖">2.1 增加 Maven 依赖&lt;/h3>
&lt;p>如果项目已经启用 Zookeeper 作为注册中心，则无需增加任何额外配置。&lt;/p>
&lt;p>如果未使用 Zookeeper 注册中心，则请参考 &lt;a href="../../registry/zookeeper/#21-%E5%A2%9E%E5%8A%A0-maven-%E4%BE%9D%E8%B5%96">为注册中心增加 Zookeeper 相关依赖&lt;/a>。&lt;/p>
&lt;h3 id="22-启用-zookeeper-配置中心">2.2 启用 Zookeeper 配置中心&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:metadata-report&lt;/span> address=&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-yaml" data-lang="yaml">&lt;span style="display:flex;">&lt;span>dubbo
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> metadata-report
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">address&lt;/span>: zookeeper://127.0.0.1:2181
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.address&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">zookeeper://127.0.0.1:2181&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>MetadataReportConfig metadataConfig &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> MetadataReportConfig();
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>metadataConfig.setAddress(&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>);
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>&lt;code>address&lt;/code> 格式请参考 &lt;a href="../../registry/zookeeper/#22-%E9%85%8D%E7%BD%AE%E5%B9%B6%E5%90%AF%E7%94%A8-zookeeper">zookeeper 注册中心 - 启用配置&lt;/a>&lt;/p>
&lt;h2 id="3-高级配置">3 高级配置&lt;/h2>
&lt;p>完整配置参数请参考 &lt;a href="../../config/properties/#metadata-report-config">metadata-report-config&lt;/a>。&lt;/p>
&lt;h2 id="4-工作原理">4 工作原理&lt;/h2>
&lt;h3 id="41-服务运维元数据overview2-服务运维元数据">4.1 &lt;a href="../overview/#2-%E6%9C%8D%E5%8A%A1%E8%BF%90%E7%BB%B4%E5%85%83%E6%95%B0%E6%8D%AE">服务运维元数据&lt;/a>&lt;/h3>
&lt;p>Zookeeper 基于树形结构进行数据存储，它的元数据信息位于以下节点:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-text" data-lang="text">&lt;span style="display:flex;">&lt;span>Provider: /dubbo/metadata/{interface name}/{version}/{group}/provider/{application name}
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Consumer: /dubbo/metadata/{interface name}/{version}/{group}/consumer/{application name}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>当 version 或者 group 不存在时，version 路径和 group 路径会取消，路径如下:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-text" data-lang="text">&lt;span style="display:flex;">&lt;span>Provider: /dubbo/metadata/{interface name}/provider/{application name}
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Consumer: /dubbo/metadata/{interface name}/consumer/{application name}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>通过 zkCli get 操作查看数据.&lt;/p>
&lt;p>Provider node:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">[&lt;/span>zk: localhost:2181&lt;span style="color:#719e07">(&lt;/span>CONNECTED&lt;span style="color:#719e07">)&lt;/span> 8&lt;span style="color:#719e07">]&lt;/span> get /dubbo/metadata/org.apache.dubbo.demo.DemoService/provider/demo-provider
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;parameters&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;anyhost&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;delay&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHello,sayHelloAsync&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;deprecated&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dynamic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;timeout&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;3000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;generic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>&lt;span style="color:#719e07">}&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;canonicalName&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;codeSource&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;file:/Users/apple/IdeaProjects/dubbo/dubbo-demo/dubbo-demo-interface/target/classes/&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#719e07">[{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHelloAsync&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;parameterTypes&amp;#34;&lt;/span>:&lt;span style="color:#719e07">[&lt;/span>&lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>&lt;span style="color:#719e07">]&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;returnType&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.util.concurrent.CompletableFuture&amp;#34;&lt;/span>&lt;span style="color:#719e07">}&lt;/span>,&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHello&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;parameterTypes&amp;#34;&lt;/span>:&lt;span style="color:#719e07">[&lt;/span>&lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>&lt;span style="color:#719e07">]&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;returnType&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>&lt;span style="color:#719e07">}]&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;types&amp;#34;&lt;/span>:&lt;span style="color:#719e07">[{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.util.concurrent.CompletableFuture&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;properties&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;result&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.lang.Object&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;stack&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.util.concurrent.CompletableFuture.Completion&amp;#34;&lt;/span>&lt;span style="color:#719e07">}}&lt;/span>,&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.lang.Object&amp;#34;&lt;/span>&lt;span style="color:#719e07">}&lt;/span>,&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.lang.String&amp;#34;&lt;/span>&lt;span style="color:#719e07">}&lt;/span>,&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.util.concurrent.CompletableFuture.Completion&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;properties&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;next&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;java.util.concurrent.CompletableFuture.Completion&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;status&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;int&amp;#34;&lt;/span>&lt;span style="color:#719e07">}}&lt;/span>,&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;int&amp;#34;&lt;/span>&lt;span style="color:#719e07">}]}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a9b1
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ctime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Mon Jun &lt;span style="color:#2aa198">28&lt;/span> 21:35:17 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a9b1
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mtime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Mon Jun &lt;span style="color:#2aa198">28&lt;/span> 21:35:17 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">pZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a9b1
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cversion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">aclVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ephemeralOwner&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x0
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataLength&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1061&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">numChildren&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Consumer node:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">[&lt;/span>zk: localhost:2181&lt;span style="color:#719e07">(&lt;/span>CONNECTED&lt;span style="color:#719e07">)&lt;/span> 10&lt;span style="color:#719e07">]&lt;/span> get /dubbo/metadata/org.apache.dubbo.demo.DemoService/consumer/demo-consumer
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;consumer&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-consumer&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;sticky&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;check&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHello,sayHelloAsync&amp;#34;&lt;/span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25aa24
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ctime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Mon Jun &lt;span style="color:#2aa198">28&lt;/span> 21:57:43 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25aa24
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mtime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Mon Jun &lt;span style="color:#2aa198">28&lt;/span> 21:57:43 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">pZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25aa24
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cversion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">aclVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ephemeralOwner&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x0
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataLength&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">219&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">numChildren&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="42-地址发现---接口-应用名映射overview11-接口---应用映射关系">4.2 &lt;a href="../overview/#11-%E6%8E%A5%E5%8F%A3---%E5%BA%94%E7%94%A8%E6%98%A0%E5%B0%84%E5%85%B3%E7%B3%BB">地址发现 - 接口-应用名映射&lt;/a>&lt;/h3>
&lt;p>在Dubbo 3.0 中，默认使用了服务自省机制去实现服务发现，关于服务自省可以查看&lt;a href="https://mercyblitz.github.io/2020/05/11/Apache-Dubbo-%E6%9C%8D%E5%8A%A1%E8%87%AA%E7%9C%81%E6%9E%B6%E6%9E%84%E8%AE%BE%E8%AE%A1/">服务自省&lt;/a>&lt;/p>
&lt;p>简而言之，服务自省机制需要能够通过 interface name 去找到对应的 application name，这个关系可以是一对多的，即一个 service name 可能会对应多个不同的 application name。在 3.0 中，元数据中心提供此项映射的能力。&lt;/p>
&lt;h5 id="zookeeper">Zookeeper&lt;/h5>
&lt;p>在上面提到，service name 和 application name 可能是一对多的，在 zookeeper 中，使用单个 key-value 进行保存，多个 application name 通过英文逗号&lt;code>,&lt;/code>隔开。由于是单个 key-value 去保存数据，在多客户端的情况下可能会存在并发覆盖的问题。因此，我们使用 zookeeper 中的版本机制 version 去解决该问题。在 zookeeper 中，每一次对数据进行修改，dataVersion 都会进行增加，我们可以利用 version 这个机制去解决多个客户端同时更新映射的并发问题。不同客户端在更新之前，先去查一次 version，当作本地凭证。在更新时，把凭证 version 传到服务端比对 version, 如果不一致说明在此期间被其他客户端修改过，重新获取凭证再进行重试(CAS)。目前如果重试6次都失败的话，放弃本次更新映射行为。&lt;/p>
&lt;p>Curator api.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>CuratorFramework client &lt;span style="color:#719e07">=&lt;/span> ...
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>client.setData().withVersion(ticket).forPath(path, dataBytes);
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>映射信息位于:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-text" data-lang="text">&lt;span style="display:flex;">&lt;span>/dubbo/mapping/{service name}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>通过 zkCli get 操作查看数据.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">[&lt;/span>zk: localhost:2181&lt;span style="color:#719e07">(&lt;/span>CONNECTED&lt;span style="color:#719e07">)&lt;/span> 26&lt;span style="color:#719e07">]&lt;/span> get /dubbo/mapping/org.apache.dubbo.demo.DemoService
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>demo-provider,two-demo-provider,dubbo-demo-annotation-provider
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a80f
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ctime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Thu Jun &lt;span style="color:#2aa198">10&lt;/span> 01:36:40 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a918
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mtime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Fri Jun &lt;span style="color:#2aa198">11&lt;/span> 18:46:40 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">pZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25a80f
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cversion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">2&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">aclVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ephemeralOwner&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x0
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataLength&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">62&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">numChildren&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="43-地址发现---接口配置元数据overview12-接口配置元数据">4.3 &lt;a href="../overview/#12-%E6%8E%A5%E5%8F%A3%E9%85%8D%E7%BD%AE%E5%85%83%E6%95%B0%E6%8D%AE">地址发现 - 接口配置元数据&lt;/a>&lt;/h3>
&lt;p>要开启远程接口配置元数据注册，需在应用中增加以下配置，因为默认情况下 Dubbo3 应用级服务发现会启用服务自省模式，并不会注册数据到元数据中心。&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span> dubbo.application.metadata-type&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">remote&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或者，在自省模式下仍开启中心化元数据注册&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-properties" data-lang="properties">&lt;span style="display:flex;">&lt;span>dubbo.application.metadata-type&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">local&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>dubbo.metadata-report.report-metadata&lt;span style="color:#719e07">=&lt;/span>&lt;span style="color:#2aa198">true&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>Zookeeper 的应用级别元数据位于 /dubbo/metadata/{application name}/{revision}&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">[&lt;/span>zk: localhost:2181&lt;span style="color:#719e07">(&lt;/span>CONNECTED&lt;span style="color:#719e07">)&lt;/span> 33&lt;span style="color:#719e07">]&lt;/span> get /dubbo/metadata/demo-provider/da3be833baa2088c5f6776fb7ab1a436
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;app&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;revision&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;da3be833baa2088c5f6776fb7ab1a436&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;services&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService:dubbo&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;protocol&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;path&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;params&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;sayHello,sayHelloAsync&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;deprecated&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;pid&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;38298&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.DemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;service-name-mapping&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;timeout&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;3000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;generic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;delay&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dynamic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;REGISTRY_CLUSTER&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;registry1&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;anyhost&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;timestamp&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1626887121829&amp;#34;&lt;/span>&lt;span style="color:#719e07">}}&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService:1.0.0:rest&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;name&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;version&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;protocol&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;rest&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;path&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;params&amp;#34;&lt;/span>:&lt;span style="color:#719e07">{&lt;/span>&lt;span style="color:#2aa198">&amp;#34;side&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;release&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;methods&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;getRemoteApplicationName,sayHello,hello,error&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;deprecated&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dubbo&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;2.0.2&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;pid&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;38298&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;interface&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.demo.RestDemoService&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;service-name-mapping&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;version&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;timeout&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;generic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;revision&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1.0.0&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;metadata-type&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;remote&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;delay&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;5000&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;application&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;dynamic&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;REGISTRY_CLUSTER&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;registry1&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;anyhost&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;true&amp;#34;&lt;/span>,&lt;span style="color:#2aa198">&amp;#34;timestamp&amp;#34;&lt;/span>:&lt;span style="color:#2aa198">&amp;#34;1626887120943&amp;#34;&lt;/span>&lt;span style="color:#719e07">}}}}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25b336
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ctime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Thu Jul &lt;span style="color:#2aa198">22&lt;/span> 01:05:55 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25b336
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">mtime&lt;/span> &lt;span style="color:#719e07">=&lt;/span> Thu Jul &lt;span style="color:#2aa198">22&lt;/span> 01:05:55 CST &lt;span style="color:#2aa198">2021&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">pZxid&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x25b336
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">cversion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">aclVersion&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">ephemeralOwner&lt;/span> &lt;span style="color:#719e07">=&lt;/span> 0x0
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">dataLength&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1286&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">numChildren&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">0&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item><item><title>Overview: Redis</title><link>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/redis/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/zh-cn/overview/mannual/java-sdk/reference-manual/metadata-center/redis/</guid><description>
&lt;p>暂未支持&lt;/p></description></item></channel></rss>