weblogic扩展domain有两种扩展，一是机器上已有要扩展的domain只是在其内增加受管服务器，二是机器上没有domain要新建domain然后增加受管服务器
一、机器上已有要扩展的domain增加受管服务器
这种情况和最开始没有受管服务器时，创建受管服务器一样操作就可以了。同一cluster应用会自动部署上去不需要再单独在其上部署应用。
第一步：登录控制台，添加好受管服务器
第二步：登录主机，到domain里配置好各受管服务器的boot.properties文件
第三步：启动各添加的受管服务器
二、机器上没有要扩展的domain，需要新建该domain然后增加受管服务器
第一步：登录控制台，添加好受管服务器
第二步：登录主机，和正常一样创建domain。domain名称、使用模式、控制台名称、控制台监听地址、控制台监听端口等等配置一定要和要加入的domain要一致
第三步：到控制台所在机器的domain中，拷贝$DOMAIN_HOME/security/SerializedSystemIni.dat文件替换新增domain中的对应文件
第四步：（如果有需要）修改jvm参数与原有机器的domain相一致，配置好和受管服务器的boot.properties文件
第五步：启动各添加的受管服务器
第二种情况与第一种情况的不同就是新增了创建domain和替换SerializedSystemIni.dat文件两步
创建domain容易理解，替换SerializedSystemIni.dat文件是因为如果不替换新增的受管服务器会报以下错误无法启动：
java.io.IOException: [DeploymentService:]Error occurred while downloading files from admin server for deployment request "1,517,380,649,343". Underlying error is: "null"
完整报错内容：
<Jan , :: PM CST> <Info> <WebLogicServer> <BEA-> <Starting WebLogic Server with Java HotSpot(TM) -Bit Server VM Version 20.45-b01 from Sun Microsystems Inc.>
java.io.IOException: [DeploymentService:]Error occurred while downloading files from admin server for deployment request "1,517,380,649,343". Underlying error is: "null"
at weblogic.deploy.service.datatransferhandlers.HttpDataTransferHandler.getDataAsStream(HttpDataTransferHandler.java:)
at weblogic.deploy.service.datatransferhandlers.DataHandlerManager$RemoteDataTransferHandler.getDataAsStream(DataHandlerManager.java:)
at weblogic.deploy.internal.targetserver.datamanagement.ConfigDataUpdate.doDownload(ConfigDataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.DataUpdate.download(DataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.Data.prepareDataUpdate(Data.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.downloadFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.updateFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.handleRegistrationResponse(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.registerHandler(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.start(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.t3.srvr.ServerServicesManager.startService(ServerServicesManager.java:)
at weblogic.t3.srvr.ServerServicesManager.startInStandbyState(ServerServicesManager.java:)
at weblogic.t3.srvr.T3Srvr.initializeStandby(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.startup(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:)
at weblogic.Server.main(Server.java:)
<Jan , :: PM CST> <Error> <Management> <BEA-> <The managed server could not update the configuration files during the registration with the deployment service. The update failed due to an exception:
weblogic.management.DeploymentException: Exception occured while downloading files
at weblogic.deploy.internal.targetserver.datamanagement.ConfigDataUpdate.doDownload(ConfigDataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.DataUpdate.download(DataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.Data.prepareDataUpdate(Data.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.downloadFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.updateFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.handleRegistrationResponse(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.registerHandler(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.start(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.t3.srvr.ServerServicesManager.startService(ServerServicesManager.java:)
at weblogic.t3.srvr.ServerServicesManager.startInStandbyState(ServerServicesManager.java:)
at weblogic.t3.srvr.T3Srvr.initializeStandby(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.startup(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:)
at weblogic.Server.main(Server.java:)
Caused By: java.io.IOException: [DeploymentService:]Error occurred while downloading files from admin server for deployment request "1,517,380,649,343". Underlying error is: "null"
at weblogic.deploy.service.datatransferhandlers.HttpDataTransferHandler.getDataAsStream(HttpDataTransferHandler.java:)
at weblogic.deploy.service.datatransferhandlers.DataHandlerManager$RemoteDataTransferHandler.getDataAsStream(DataHandlerManager.java:)
at weblogic.deploy.internal.targetserver.datamanagement.ConfigDataUpdate.doDownload(ConfigDataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.DataUpdate.download(DataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.Data.prepareDataUpdate(Data.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.downloadFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.updateFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.handleRegistrationResponse(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.registerHandler(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.start(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.t3.srvr.ServerServicesManager.startService(ServerServicesManager.java:)
at weblogic.t3.srvr.ServerServicesManager.startInStandbyState(ServerServicesManager.java:)
at weblogic.t3.srvr.T3Srvr.initializeStandby(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.startup(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:)
at weblogic.Server.main(Server.java:)
>
<Jan , :: PM CST> <Critical> <WebLogicServer> <BEA-> <Server failed. Reason: There are nested errors: weblogic.management.DeploymentException: Exception occured while downloading files
at weblogic.deploy.internal.targetserver.datamanagement.ConfigDataUpdate.doDownload(ConfigDataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.DataUpdate.download(DataUpdate.java:)
at weblogic.deploy.internal.targetserver.datamanagement.Data.prepareDataUpdate(Data.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.downloadFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.updateFiles(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.handleRegistrationResponse(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.registerHandler(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.management.provider.internal.RuntimeAccessDeploymentReceiverService.start(RuntimeAccessDeploymentReceiverService.java:)
at weblogic.t3.srvr.ServerServicesManager.startService(ServerServicesManager.java:)
at weblogic.t3.srvr.ServerServicesManager.startInStandbyState(ServerServicesManager.java:)
at weblogic.t3.srvr.T3Srvr.initializeStandby(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.startup(T3Srvr.java:)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:)
at weblogic.Server.main(Server.java:)
Caused by: java.io.IOException: [DeploymentService:]Error occurred while downloading files from admin server for deployment request "1,517,380,649,343". Underlying error is: "null"
at weblogic.deploy.service.datatransferhandlers.HttpDataTransferHandler.getDataAsStream(HttpDataTransferHandler.java:)
at weblogic.deploy.service.datatransferhandlers.DataHandlerManager$RemoteDataTransferHandler.getDataAsStream(DataHandlerManager.java:)
at weblogic.deploy.internal.targetserver.datamanagement.ConfigDataUpdate.doDownload(ConfigDataUpdate.java:)
... more >
<Jan , :: PM CST> <Notice> <WebLogicServer> <BEA-> <Server state changed to FAILED>
<Jan , :: PM CST> <Error> <WebLogicServer> <BEA-> <A critical service failed. The server will shut itself down>
参考：