Type	NEW
Priority	HIGH
Status	CLOSED

Topic	Multiple xmlBlaster server instances can register themselves in a CORBA NameService
Des cription	Clients can lookup an xmlBlaster server with a CORBA NameService. The xmlBlaster servers register themselves in a hierarchical manner in the NameService as shown in the following illustration: In this example there are three xmlBlaster server running which have registered themselves under their cluster.node.id names heron, avalon and frodo. Clients can query the root context xmlBlaster.MOM to choose a server they want to connect to. When a server shuts down it removes its NameService entry. If a server crashes (e.g. by kill -9) it can't remove the NameService entry, but on startup it will overwrite the previous setting.
Example JAVA	Here we show an example which plays with NameService entries, please start all instances in a separate DOS-box or xterm. We assume that you have started a NameService and the IOR of the NameService is dumped to /tmp/ns.ior, here are examples how to start the JacORB NameService (delivered with the xmlBlaster distribution) or the ORBIX NameService (see http://www.iona.com): # Start the JacORB NameService # (the port 7608 is looked for automatically by xmlBlaster server): jaco -DOAPort=7608 org.jacorb.naming.NameServer /tmp/ns.ior # The ORBIX NameService: /opt/orbix/etc/bin> start_XX_services # query the IOR (for ORBIX only) itadmin % ns resolve IOR:010000002800000049... # Put this IOR into /tmp/ns.ior Now we are ready to start some servers and a client. We have set -trace[corba] true to get more logging output from the CORBA plugin, further we have set -bootstrapPort 0 to suppress internal IOR download (as we want to test the NameService). We choose another telnet access port for the second and third server with -admin.remoteconsole.port 270x to avoid a conflict and an ugly error output. # Start heron: java -DORBInitRef.NameService=file:///tmp/ns.ior -jar lib/xmlBlaster.jar -trace[corba] true -bootstrapPort 0 -cluster.node.id heron # Start avalon: java -DORBInitRef.NameService=file:///tmp/ns.ior -jar lib/xmlBlaster.jar -trace[corba] true -bootstrapPort 0 -admin.remoteconsole.port 2703 -cluster.node.id avalon # Start frodo: java -DORBInitRef.NameService=file:///tmp/ns.ior -jar lib/xmlBlaster.jar -trace[corba] true -bootstrapPort 0 -admin.remoteconsole.port 2704 -cluster.node.id frodo # If you use the ORBIX NameService you can check the entries: % ns list xmlBlaster.MOM Context % ns list xmlBlaster.MOM frodo.MOM Object heron.MOM Object avalon.MOM Object # Now start a client: java -DORBInitRef.NameService=file:///tmp/ns.ior -cp lib/xmlBlaster.jar HelloWorld2 # OOppps, you got an error as the client does not know which server to choose, # we choose avalon java -DORBInitRef.NameService=file:///tmp/ns.ior -cp lib/xmlBlaster.jar HelloWorld2 -trace[CORBA] true -NameService.node.id avalon
Configure	These parameters allow to configure the NameService entries on server side and to specify the desired lookup on client side. Property Default / Example Description Impl plugin/ior/useNameService true If set to true, xmlBlaster tries to register itself in a NameService NameService.context.id xmlBlaster The root context entry in the NameService, it defaults to xmlBlaster NameService.context.kind MOM The kind of service is set to MOM NameService.node.id [The xmlBlaster server name] This property is set as default to the name of the server instance (the value of -cluster.node.id). You can overwrite it by setting this property. NameService.node.kind MOM The kind of service is set to MOM java -DORBInitRef.NameService corbaloc:iiop:localhost:7608/StandardNS/NameServer-POA/_root XmlBlaster is configured to automatically lookup a NameService on port 7608 on localhost (see xmlBlaster/config/ jacorb.properties.template), here it is set as JVM property. Note: You can set this property as command line argument as well like -ORBInitRef NameService=file:///tmp/ns.ior NOTE: Configuration parameters are specified on command line (-someValue 17) or in the xmlBlaster.properties file (someValue=17). See requirement "util.property" for details. Columns named Impl tells you if the feature is implemented. Columns named Hot tells you if the configuration is changeable in hot operation.
See REQ	protocol
See REQ	protocol.corba.JacORB
See CODE	org.xmlBlaster.protocol.corba.CorbaDriver
See CODE	org.xmlBlaster.client.protocol.corba.CorbaConnection

This page is generated from the requirement XML file xmlBlaster/doc/requirements/protocol.corba.NameService.xml

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