在Nacos中，这有可能是什么原因呢？1. 表象：nacos 客户端连不上服务端（拿不到配置内容）

1. 看日志 $HOME/logs/nacos/remote.log 提示 9848 端口无法连接。
2. 在客户端 telnet 服务端 9848 端口是通的（实际上客户端和服务段在同一台主机上）。
3. nacos 是通过 docker 方式气动的，一开始映射了 8848，9848 端口出来，连不上，后面干脆指定了 --network=host 客户端也连不上。灵异甚至诡异的一个情况是：我通过 SSH 的端口转发功能把服务器的 8848, 9848 端口转发到本地，然后本地用相同的命令启动相同的 jar 包，是可以读取到 nacos 配置的。我在服务器用 SSH 的端口转发功能把 8848， 9848 端口转发到 3333, 4333，启动 jar 包，也是报错连接不上 4333。
   客户端报错：
   Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
   2024-08-19 14:42:36 [main] ERROR org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter -

APPLICATION FAILED TO START

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class

Action:

Consider the following:
If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
If you have database settings to be loaded from a particular profile you may need to activate it (the profiles test are currently active).

2024-08-19 14:42:36 [Thread-11] WARN com.alibaba.nacos.common.http.HttpClientBeanHolder -[HttpClientBeanHolder] Start destroying common HttpClient
2024-08-19 14:42:36 [Thread-11] WARN com.alibaba.nacos.common.http.HttpClientBeanHolder -[HttpClientBeanHolder] Destruction of the end
2024-08-19 14:42:36 [Thread-28] WARN com.alibaba.nacos.common.notify.NotifyCenter -[NotifyCenter] Start destroying Publisher

2024-08-19 14:42:36 [Thread-28] WARN com.alibaba.nacos.common.notify.NotifyCenter -[NotifyCenter] Destruction of the end

$HOME/logs/nacos/remote.log:
2024-08-19 14:41:52.732 INFO [main :c.a.n.c.r.client] [RpcClientFactory] create a new rpc client of 63b64116-f778-4cee-b22f-0d427f07f3cc_config-0
2024-08-19 14:41:52.755 INFO [main :c.a.n.c.r.client] [63b64116-f778-4cee-b22f-0d427f07f3cc_config-0] Register server push request handler:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$$Lambda$359/1489092624
2024-08-19 14:41:52.755 INFO [main :c.a.n.c.r.client] [63b64116-f778-4cee-b22f-0d427f07f3cc_config-0] Register server push request handler:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$$Lambda$360/192881625
2024-08-19 14:41:52.756 INFO [main :c.a.n.c.r.client] [63b64116-f778-4cee-b22f-0d427f07f3cc_config-0] Registry connection listener to current client:com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$1
2024-08-19 14:41:52.756 INFO [main :c.a.n.c.r.client] [63b64116-f778-4cee-b22f-0d427f07f3cc_config-0] RpcClient init, ServerListFactory = com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient$2
2024-08-19 14:41:52.765 INFO [main :c.a.n.c.r.client] [63b64116-f778-4cee-b22f-0d427f07f3cc_config-0] Try to connect to server on start up, server: {serverIp = 'localhost', server main port = 3333}
2024-08-19 14:41:52.791 INFO [main :c.a.n.c.r.c.g.GrpcClient] grpc client connection server:localhost ip,serverPort:4333,grpcTslConfig:{"sslProvider":"","enableTls":false,"mutualAuthEnable":false,"trustAll":false}
2024-08-19 14:41:56.223 ERROR [main :c.a.n.c.r.c.g.GrpcClient] Server check fail, please check server localhost ,port 4333 is available , error ={}
java.util.concurrent.TimeoutException: Waited 3000 milliseconds (plus 407320 nanoseconds delay) for com.alibaba.nacos.shaded.io.grpc.stub.ClientCalls$GrpcFuture@52aa2946[status=PENDING, info=[GrpcFuture{clientCall=PendingCall{realCall=ClientCallImpl{method=MethodDescriptor{fullMethodName=Request/request, type=UNARY, idempotent=false, safe=false, sampledToLocalTracing=true, requestMarshaller=com.alibaba.nacos.shaded.io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller@4de5031f, responseMarshaller=com.alibaba.nacos.shaded.io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller@67e2d983, schemaDescriptor=com.alibaba.nacos.api.grpc.auto.RequestGrpc$RequestMethodDescriptorSupplier@5d47c63f}}}}]]
at com.alibaba.nacos.shaded.com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:508) ~[nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.common.remote.client.grpc.GrpcClient.serverCheck(GrpcClient.java:218) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.common.remote.client.grpc.GrpcClient.connectToServer(GrpcClient.java:329) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.common.remote.client.RpcClient.start(RpcClient.java:363) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient.ensureRpcClient(ClientWorker.java:891) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient.getOneRunningClient(ClientWorker.java:1038) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.impl.ClientWorker$ConfigRpcTransportClient.queryConfig(ClientWorker.java:946) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.impl.ClientWorker.getServerConfig(ClientWorker.java:403) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.NacosConfigService.getConfigInner(NacosConfigService.java:184) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.nacos.client.config.NacosConfigService.getConfig(NacosConfigService.java:96) [nacos-client-2.2.3.jar!/:na]
at com.alibaba.cloud.nacos.client.NacosPropertySourceBuilder.loadNacosData(NacosPropertySourceBuilder.java:85) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceBuilder.build(NacosPropertySourceBuilder.java:73) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceLocator.loadNacosPropertySource(NacosPropertySourceLocator.java:199) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceLocator.loadNacosDataIfPresent(NacosPropertySourceLocator.java:186) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceLocator.loadNacosConfiguration(NacosPropertySourceLocator.java:158) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceLocator.loadSharedConfiguration(NacosPropertySourceLocator.java:116) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at com.alibaba.cloud.nacos.client.NacosPropertySourceLocator.locate(NacosPropertySourceLocator.java:101) [spring-cloud-starter-alibaba-nacos-config-2021.0.5.0.jar!/:2021.0.5.0]
at org.springframework.cloud.bootstrap.config.PropertySourceLocator.locateCollection(PropertySourceLocator.java:51) [spring-cloud-context-3.1.6.jar!/:3.1.6]
at org.springframework.cloud.bootstrap.config.PropertySourceLocator.locateCollection(PropertySourceLocator.java:47) [spring-cloud-context-3.1.6.jar!/:3.1.6]
at org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration.initialize(PropertySourceBootstrapConfiguration.java:95) [spring-cloud-context-3.1.6.jar!/:3.1.6]
at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:604) [spring-boot-2.7.12.jar!/:2.7.12]
at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:373) [spring-boot-2.7.12.jar!/:2.7.12]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:306) [spring-boot-2.7.12.jar!/:2.7.12]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303) [spring-boot-2.7.12.jar!/:2.7.12]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292) [spring-boot-2.7.12.jar!/:2.7.12]
at com.eshore.bim.Application.main(Application.java:21) [classes!/:0.5.0-SNAPSHOT]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_272]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_272]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_272]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_272]
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49) [bim-data.jar:0.5.0-SNAPSHOT]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:108) [bim-data.jar:0.5.0-SNAPSHOT]
at org.springframework.boot.loader.Launcher.launch(Launcher.java:58) [bim-data.jar:0.5.0-SNAPSHOT]
at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:65) [bim-data.jar:0.5.0-SNAPSHOT]