Singleton Service in Cluster

Has anybody created the singleton servince in cluster and migrated once the server goes down. If so can you please share the sameple and steps for the migration.
Thanks,

Here is an example on how to create a singleton service: http://middlewaremagic.com/weblogic/?p=5799
Example on configuring migration can be found here: http://middlewaremagic.com/weblogic/?p=7188

Similar Messages

Singleton service/task in a cluster

I have a timer that schecules multiple task. This runs fine in a single JVM.
When I cluster using coherence does coherence provide any framework to convert this task to a singleton service so that only a node in the cluster executes it?
Thanks
Kumar Pandey

Hi Kumar,
Yes, WorkManager is clearly one way to do it. It is most useful when your tasks come from a single client thread.
In a scenario, when you have many clients in a cluster that may want to execute the same task at the same time, a concurrency API could be an answer. Please see this postas an example for using this pattern.
Regards,
Gene

Error with running Singleton Service in a non-clustered mode

Hello,
I'm getting this error when try to deploy an app with defined Singleton Service in a WebLogic 10.3.5:
<Error> <Deployer> <localdomain> <AdminServer><[ACTIVE] ExecuteThread: '1' for queue: 'weblogic.kernel.Default(self-tuning)'> <<WLS Kernel>> <><7785ef355ffde3d6:-4c7bfbbc:138dd48f82b:-8000-0000000000000002><1343742871514> <BEA-149231> <Unable to set the activation state to true for the application 'MyApp'.
weblogic.management.DeploymentException:
at weblogic.application.internal.flow.SingletonServicesFlow.activate(SingletonServicesFlow.java:67)
at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:636)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:205)
at weblogic.application.internal.EarDeployment.activate(EarDeployment.java:58)
at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161)
at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79)
at weblogic.deploy.internal.targetserver.BasicDeployment.activate(BasicDeployment.java:184)
at weblogic.deploy.internal.targetserver.BasicDeployment.activateFromServerLifecycle(BasicDeployment.java:361)
at weblogic.management.deploy.internal.DeploymentAdapter$1.doActivate(DeploymentAdapter.java:52)
at weblogic.management.deploy.internal.DeploymentAdapter.activate(DeploymentAdapter.java:200)
at weblogic.management.deploy.internal.AppTransition$2.transitionApp(AppTransition.java:31)
at weblogic.management.deploy.internal.ConfiguredDeployments.transitionApps(ConfiguredDeployments.java:240)
at weblogic.management.deploy.internal.ConfiguredDeployments.activate(ConfiguredDeployments.java:170)
at weblogic.management.deploy.internal.ConfiguredDeployments.deploy(ConfiguredDeployments.java:124)
at weblogic.management.deploy.internal.DeploymentServerService.resume(DeploymentServerService.java:181)
at weblogic.management.deploy.internal.DeploymentServerService.start(DeploymentServerService.java:97)
at weblogic.t3.srvr.SubsystemRequest.run(SubsystemRequest.java:64)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)
Caused By: java.lang.IllegalArgumentException: Cannot add Singleton Service MySingletonService as SingletonServicesManager not started. Check if MigrationBasis for cluster is configured.
at weblogic.cluster.singleton.SingletonServicesManager.addConfiguredService(SingletonServicesManager.java:280)
at weblogic.cluster.singleton.SingletonServicesManager.addConfiguredService(SingletonServicesManager.java:297)
at weblogic.application.internal.flow.SingletonServicesFlow.activate(SingletonServicesFlow.java:65)
at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:637)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:54)
at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:205)
at weblogic.application.internal.EarDeployment.activate(EarDeployment.java:58)
at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161)
at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79)
at weblogic.deploy.internal.targetserver.BasicDeployment.activate(BasicDeployment.java:184)
at weblogic.deploy.internal.targetserver.BasicDeployment.activateFromServerLifecycle(BasicDeployment.java:361)
at weblogic.management.deploy.internal.DeploymentAdapter$1.doActivate(DeploymentAdapter.java:52)
at weblogic.management.deploy.internal.DeploymentAdapter.activate(DeploymentAdapter.java:200)
at weblogic.management.deploy.internal.AppTransition$2.transitionApp(AppTransition.java:31)
at weblogic.management.deploy.internal.ConfiguredDeployments.transitionApps(ConfiguredDeployments.java:240)
at weblogic.management.deploy.internal.ConfiguredDeployments.activate(ConfiguredDeployments.java:170)
at weblogic.management.deploy.internal.ConfiguredDeployments.deploy(ConfiguredDeployments.java:124)
at weblogic.management.deploy.internal.DeploymentServerService.resume(DeploymentServerService.java:181)
at weblogic.management.deploy.internal.DeploymentServerService.start(DeploymentServerService.java:97)
at weblogic.t3.srvr.SubsystemRequest.run(SubsystemRequest.java:64)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)
It gets run only after deleting singleton-service entry from weblogic-application.xml:
<singleton-service>
<class-name>my.app.SingletonClass</class-name>
<name>MySingletonService</name>
</singleton-service>
Is it possible to run it in a non-clustered server without deleting Singleton entry from weblogic-application.xml?
Thanks

Did this help you ??
Not sure if it's related as here the issue is with clustered/non clustred and versioning!! the application which the bug talks about.

Singleton service example

Hi
          In order to create and deploy a singleton service on WebLogic 92, I did exactly as the book said (http://edocs.bea.com/wls/docs92/cluster/migration.html#wp1045262). But it didn't work.
          So I wish to find a tested example (all required files), or an artical that describes the whole process of creating and deploying a singleton-service, with one of you.
          Thx in advanse

Hi,
          I'm runing into issues trying to build a simple singleton service. Actually, I do not even know how to invoke methods on the singleton. I guess there is not enough documentation on this. Just curious whether or not you get this working. I will really appreciate it if you can share some ideas/knowledge.
          Thanks, Adam

Singleton service

Hi guys
I tried to create singleton service by implement SingletonService interface which provided by weblogic.
And configure singleton service in
weblogic-application.xml file.
And define singleton service in
environment->cluster->singleton service tab in weblogic console.
I used to create Singleton service instance like such a way
SingletonServiceTest singletonServiceTest =
(SingletonServiceTest)SingletonServicesManager.
getInstance().
getService("SingletonServiceTest");
Problem was
SingletonServicesManager give the different singleton service instance for different server.

I have partial solution now:
For proper work of SingletonService, the servers (cluster nodes) must be run using node manager. Then SingletonService as pure java class works - methods activate and deactivate are called as expected.
However it seems, that MDB cannot be a SingletonService.
zmach

Singletons in WebLogic cluster

In my clustered EJB application, there are 3 stateless session beans that need to run as singleton services on exactly one node. So I implemented the interface weblogic.cluster.singleton.SingletonService in these beans with the activate and deactivate methods. The beans and all classes of the application are contained in an ear file I deploy to the entire cluster. Then I configured the bean classes as singletons using the WebLogic console administration (cluster details -> singleton service). After I activated this in changes center, I see a ClassNotFoundException with the class name of one of the beans. So I extracted the ear file to the domain/lib directory, restarted the server and tried again to configure the singleton classes. This time the activation failed because of another reason (HibernateException). I think the reason is, this operation is done in the context of my administration server, not of the cluster server. It seems this doesn't work.
Is it possible to deploy the EJB application with the beans as singletons?
I already found another solution: to set the maximum number of beans in weblogic-ejb-jar.xml, field max-beans-in-free-pool, to 1. This solution is a little bit dirty, after starting the servers, I get an exception on all other nodes complaining that it is not possible to deploy this bean. What I don't know: how would it be handled, if the node with the deployed beans is shut down? Are the beans deployed on the other nodes automatically (as I expect for singleton services) or keep undeployed?
Thanks in advance!
BTW: I'm using WebLogic 10.3 on Windows.

Maybe this will help: http://middlewaremagic.com/weblogic/?p=5799
Also to make Hibernate run on WebLogic you have perform certain steps, there is
problem with the antlr version that ships with Hibernate as another version of
antlr is already loaded in the system classpath of WebLogic.
Some instructions are presented here: http://middlewaremagic.com/weblogic/?p=5861

Singleton deployed in cluster runs in both managed servers

Hi,
I have deployed a singleton service in a Weblogic (9.2) cluster. This cluster has two managed servers.
Recently we saw instances of this singleton services running on both these managed servers, which resulted in a lot of duplicate data in our system.
Is this a bug in the system? How can we prevent this?

Hi,
Could you please refer the following links and confirm me if you had defined and configured the singleton service as mentioned in the links:
http://download.oracle.com/docs/cd/E13222_01/wls/docs92/ConsoleHelp/taskhelp/clusters/ConfigureSingletonService.html
http://download.oracle.com/docs/cd/E13222_01/wls/docs92/ConsoleHelp/taskhelp/clusters/DefineSingletonService.html
regards,
Zeno

Weblogic Singleton Service concurrent updates

Our environment has 1 cluster with 4 managed servers(each in a different physical servers).We have a requirement to maintain a cache which is transparent to all the 4 servers(only one copy is expected to be available at any point of time in the cluster) . This cache contains hashmap which gets updated every millisecond by clients performing calculations.This cache does not grow in volume overtime but has very frequent updates. We plan to implement a weblogic singleton service to handle this caching requirement .
1. Based on your past experience, Is weblogic singleton an ideal candidate for such a requirement. Does this introduce any delay because of synchronizing between the 4 managed servers? This will be used by the pricing engine and we do not want this to introduce any additional delay using this technology.
2. Also can you let me know what is the underlying technology weblogic(does it use IP multicast??? or do we have a choice choosing either IP socket, ip unicast or mulicast) uses to syncronize the data in singleton object with the managed servers.
3. Can I have this setup without a nodemanager as nodemanages are not allowed in our environment. According to what I read from weblogic documentation, nodemanager is required if we use consensus leasing only.If I choose to use database leasing, node manager is not required. Is that true?
Thanks for your help.

I'd be seriously looking at Oracle Coherence, which is specifically designed to solve this sort of distributing caching/map problem.
http://coherence.oracle.com/display/COH/Oracle+Coherence+Knowledge+Base+Home
-steve-

How to implement singleton service if i m using only jar and war component

hello,
in my application i m using only jar and war component .
as i m not using EAR for deployment so i dont have weblogic-application.xml file.
so in this case how i implement weblogic singleton service .and how to call active method

From the documentation:
After you have created a singleton service class using the SingletonService interface, you must define it as a singleton service within WebLogic Server. This singleton service object contains the following information:
The path to the class to load as the singleton service.
The preferred server and other candidate servers for the singleton service.
The following excerpt from the cluster element of config.xml shows how a singleton service is defined:
<singleton-service>
<name>SingletonTestServiceName</name>
<user-preferred-server>myManaged1</user-preferred-server>
<class-name>mycompany.myprogram.subpackage.SingletonTestServiceImpl</class-name>
<cluster>myCluster</cluster>
</singleton-service>
Note that the config.xml is located in the <domain-home>/config directory

Admin Server Shows Singleton Services Manager not started

Hi,
I have an environment with 1 Admin Server and 2 Managed Servers in the cluster.
I am using Migration basis as database for the cluster. I checked by installing one singleton service that it is working fine in cluster.
Then I created one migratable target having auto migration as the migration policy and migratable target is also working as expected.
Now the problem is whenever I start my Admin Server it is throwing exception:
Cannot add Singleton Service <Migratable Target Name> as Singleton not started. Check if MigrationBasis for cluster is configured.
Anyone is having any idea about this problem, what can be the issue is?
Thanks in Advance

Hi Ramprakash Arun,
To prevent the java.net.BindException, use a unique combination of the IP:port as the listen address for every channel configured on the server. No other process should be listening on that address (IP:port).
Using netstat, verify whether the port specified is already in use by another process or not. Also check if the listen address is valid (using ipconfig/ifconfig).
Regards,
Vijaya

Weblogic clustering - share a singleton services without implementing weblogic singletonService interface

I have a singleton object java object in my application , when i deploy my application in clustering each cluster node creates a separate singleton object thus data integrity is lost. More over I am not in a position to change any of my code with specific to web-logic and implement any third party library such as teracotta.
Can any one help me out of it in how to maintain the data integrity between the cluster nodes . Thanks in Advance

Hi,
I'm not sure if singleton services works with stateless session beans. By other hand, I understand as follow:-
1. After you have created a singleton service class using the SingletonService interface, you must define it as a singleton service within WebLogic Server, see http://download.oracle.com/docs/cd/E1284001/wls/docs103/ConsoleHelp/taskhelp/clusters/ConfigureSingletonService.html_
2. A singleton service is a service (application) on a cluster that is available and active on only one server at any given time, you must deploy the service on only one member of the cluster.
3. For high avalability, you must implement WebLogic Service Migration for your singleton service, see http://download.oracle.com/docs/cd/E1284001/wls/docs103/cluster/service_migration.html#wp1051458_
4. The clients connecting to the service, you must implement a special mechanism. See http://download.oracle.com/docs/cd/E1322201/wls/docs81/jndi/jndi.html#475689_

Is Singleton service available in oracle application server

Is Singleton service available in oracle application server
if yes please provide documentation

Hi,
what do you mean with singleton service? I know singletons as a design pattern in J2EE, so you may have to provide more information to get this question answered.
Frank

Implementing Singletons in a cluster

Hi all,
I have the following question: is it possible to implement a Singleton in a EJB
cluster? What about using a Stateless Session Bean with max-cache setting to 1
?(for container that support it). This way the container will create a single
instance and serialize access to it....what do you think about it??
Francesco

Hello,
I recalled this time-ago posting. I'd like to
expand it a bit.
bind a remote object to a jndi entry.
That won't work with Weblogic ... it is possible to end up >with two singletonsdue to how WL JNDI works.
Why binding a remote object in JNDI tree will end up with
more instance of the object? Pardon my un-experience with clustering but I thought
WL replicates JNDI
tree between instances in the cluster....why other instance
of the cluster don't get the same replica-object?
A further issue: are there any problems with using a static field in an EJB that's
in a cluster?
Thanks a lot
Francesco
"Cameron Purdy" <[email protected]> wrote:
That won't work with Weblogic ... it is possible to end up with two
singletons due to how WL JNDI works.
Peace,.
Cameron Purdy
Tangosol, Inc.
Clustering Weblogic? You're either using Coherence, or you should be!
Download a Tangosol Coherence eval today at http://www.tangosol.com/
"tony pan" <[email protected]> wrote in message
news:3cab973a$[email protected]..
If you really want to do it, bind a remote object to a jndi entry.ServerSide has
an example. But be sure it is really what you want.
"Cameron Purdy" <[email protected]> wrote:
What are you trying to accomplish with a singleton in the cluster?
Peace,
Cameron Purdy
Tangosol, Inc.
Clustering Weblogic? You're either using Coherence, or you should
be!
Download a Tangosol Coherence eval today at http://www.tangosol.com/
"Francesco" <[email protected]> wrote in message
news:[email protected]..
Hi all,
I have the following question: is it possible to implement a Singletonin
a EJB
cluster? What about using a Stateless Session Bean with max-cache
setting
to 1
?(for container that support it). This way the container will createa
single
instance and serialize access to it....what do you think about it??
Francesco

Failing "List Services Information" Cluster validation test

Hi
I'm building a 2 node Windows 2008 SP2 Cluster. I've setup the SAN Disks, NIcs etc and am running the cluster validation tests. However this always fails on the "List Services Information" Test with the following error statement:
"An error occurred while executing the test. There was an error getting information about the running services on the nodes. There was an error retrieving information about the Services from node '<Server FQDN>'. Object reference not set to an
instance of an object.
Note: I replaced the actual server fqdn with <Server FQDN>
Any help is appreciated.
Thanks

Hi,
I know it is not a SQL cluster but you could still have a try with steps below as a workaround. See:
http://support.microsoft.com/kb/953748/en-us
•For an integrated failover Add-Note setup, run the following command on each node that is being added:
Setup /SkipRules=Cluster_VerifyForErrors /Action=InstallFailoverCluster
•For an advanced or enterprise installation, run the following command:
Setup /SkipRules=Cluster_VerifyForErrors /Action=CompleteFailoverCluster
•If you receive this validation failure when you add a node to an existing failover installation, run the following command on each node that is being added:
Setup /SkipRules=Cluster_VerifyForErrors /Action=AddNode
TechNet Subscriber Support in forum |If you have any feedback on our support, please contact [email protected]

Clustered Singleton Service in WLS?

Hello,
          I'm working on a clustered system that needs a distributed
          singleton. Specifically I need a timer/listener pair that
          will do work in the system, but I it would be bad to have
          more than one listener fired off within the cluster.
          How can I design this feature such that:
          1) There is only one active timer/listener in the clustered
          app active at any one time
          2) If this active instance dies, another somewhere in the
          cluster will be spooled up to take its place?
          I'm considering some kind of JXTA-based solution but before
          I invest a lot of energy in that direction I want to be
          sure I'm not trying to kill a fly with a bazooka.
          Thanks
          Greg


I'm working on a clustered system that needs a distributed          > singleton. Specifically I need a timer/listener pair that
          > will do work in the system, but I it would be bad to have
          > more than one listener fired off within the cluster.
          > 1) There is only one active timer/listener in the clustered
          > app active at any one time
          > 2) If this active instance dies, another somewhere in the
          > cluster will be spooled up to take its place?
          See the clustered singleton example using Coherence:
          http://www.tangosol.net/forums/thread.jspa?forumID=6&threadID=82&tstart=0
          Peace,
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com/coherence.jsp
          Tangosol Coherence: Clustered Replicated Cache for Weblogic
          "Greg" <[email protected]> wrote in message
          news:[email protected]..
          >

Singleton Service in Cluster

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