• Dubbo version: 2.7.15(2.7.7测试也存在)
• nacos version: 2.0.2
• Operating System version: macos12、centos7
• Java version: 1.8

复现

nacos：重启nacos或者使用新的一个ip启动provider应用

dubbo：

首先新建一个自定义Dispatcher

public class TestDispatcher implements Dispatcher {
    public static final String NAME = "test";
    @Override
    public ChannelHandler dispatch(ChannelHandler handler, URL url) {
        return new MessageOnlyChannelHandler(handler, url);
    }
}

同时在META-INFO.dubbo中也创建对应文件

在配置中指定：

dubbo.protocol.dispatcher=test

启动服务后，nacos注册成功，可以看到dispatcher等信息都是成功注册的，同时consumer在nacos上也可以看到

{
	"side": "provider",
	"service.name": "ServiceBean:/xxx.xxx.demo.serivce.SayService",
	"methods": "sayHelloByName",
	"release": "2.7.15",
	"deprecated": "false",
	"dubbo": "2.0.2",
	"threads": "5",
	"pid": "77518",
	"interface": "xxx.xxx.demo.serivce.SayService",
	"threadpool": "fixed",
	"generic": "false",
	"corethreads": "5",
	"path": "xxx.xxx.demo.serivce.SayService",
	"protocol": "dubbo",
	"metadata-type": "remote",
	"application": "provider-service",
	"dynamic": "true",
	"category": "providers",
	"dispatcher": "test",
	"anyhost": "true",
	"threadname": "default-thread",
	"timestamp": "1643015362814"
}

但是调用服务会失败：

Failed to invoke the method sayHelloByName in the service xxx.xxx.demo.serivce.SayService. No provider available for the service xxx.xxx.demo.serivce.SayService from registry 127.0.0.1:8848 on the consumer 10.179.116.54 using the dubbo version 2.7.15. Please check if the providers have been started and registered.

如何调用成功

在配置中修改dispatcher为message，启动服务注册成功后，再将dispatcher改为test，重启服务，consumer便可以成功调用

dubbo.protocol.dispatcher=message

但是线上k8s等服务ip可能会改变，不可能使用改dispatcher重启等方法让consumer调用

暂时的解决办法

将自定义的dispatcher的name定义为dubbo已有的，比如message，覆写该dispatcher，便可以直接调用成功