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

Similar Messages

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

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

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_

Reporting Services as a generic service in a failover cluster group?

There is some confusion on whether or not Microsoft will support a Reporting Services deployment on a failover cluster using scale-out, and adding the Reporting Services service as a generic service in a cluster group to achieve active-passive high
availability.
A deployment like this is described by Lukasz Pawlowski (Program Manager on the Reporting Services team) in this blog article
http://blogs.msdn.com/b/lukaszp/archive/2009/10/28/high-availability-frequently-asked-questions-about-failover-clustering-and-reporting-services.aspx. There it is stated that it can be done, and what needs to be considered when doing such a deployment.
This article (http://technet.microsoft.com/en-us/library/bb630402.aspx) on the other hand states: "Failover clustering is supported only for the report server database; you
cannot run the Report Server service as part of a failover cluster."
This is somewhat confusing to me. Can I expect to receive support from Microsoft for a setup like this?
Best Regards,
Peter Wretmo

Hi Peter,
Thanks for your posting.
As Lukasz said in the
blog, failover clustering with SSRS is possible. However, during the failover there is some time during which users will receive errors when accessing SSRS since the network names will resolve to a computer where the SSRS service is in the process of starting.
Besides, there are several considerations and manual steps involved on your part before configuring the failover clustering with SSRS service:
Impact on other applications that share the SQL Server. One common idea is to put SSRS in the same cluster group as SQL Server. If SQL Server is hosting multiple application databases, other than just the SSRS databases, a failure in SSRS may cause
a significant failover impact to the entire environment.
SSRS fails over independently of SQL Server.
If SSRS is running, it is going to do work on behalf of the overall deployment so it will be Active. To make SSRS Passive is to stop the SSRS service on all passive cluster nodes.
So, SSRS is designed to achieve High Availability through the Scale-Out deployment. Though a failover clustered SSRS deployment is achievable, it is not the best option for achieving High Availability with Reporting Services.
Regards,
Mike Yin
If you have any feedback on our support, please click
here
Mike Yin
TechNet Community Support

Unable to failover the services in active-active cluster node

Hi,
i am applying the sp2 patch for sql server 2008 r2 in active-active cluster, we have 3 services in the cluster , node 1 as 2 prefered owner and node 2 as 1 prefered owner, when i try to move the service from node 2 to node1 , i am getting the below errors
DCOM was unable to communicate with the computer XXXXXXXXX using any of the configured protocols.
The Kerberos client received a KRB_AP_ERR_MODIFIED error from the server XXXXXXXXX. The target name used was RPCSS/XXXXXX. This indicates that the target server failed to decrypt the ticket provided by the client. This can occur when the target server principal
name (SPN) is registered on an account other than the account the target service is using. Please ensure that the target SPN is registered on, and only registered on, the account used by the server. This error can also happen when the target service is using
a different password for the target service account than what the Kerberos Key Distribution Center (KDC) has for the target service account. Please ensure that the service on the server and the KDC are both updated to use the current password. If the server
name is not fully qualified, and the target domain (XXXXXX) is different from the client domain (XXXXXXX), check if there are identically named server accounts in these two domains, or use the fully-qualified name to identify the server.
The Cluster service failed to bring clustered service or application 'CHCROCHC045' completely online or offline. One or more resources may be in a failed state. This may impact the availability of the clustered service or application.
Cluster resource 'SQL Server (CHCROCHC045)' in clustered service or application 'CHCROCHC045' failed.
any inputs appreciated to resolve this issue as i could not procedd with patching
BR
PGR

Hi PGR,
As the issue is more related to Windows Server, I would like to recommend you post the issue in the
Windows Server forums for better support.
In addition, below are some article about troubleshooting error ” DCOM was unable to communicate with the computer XXXXXXXXX using any of the configured protocols” for your reference.
Event ID 10009 — COM Remote Service Availability
How to troubleshoot DCOM 10009 error logged in system event?
Thanks,
Lydia Zhang
Lydia Zhang
TechNet Community Support

Web Service Task - XML Task - values are empty while trying to read from XPATH. Can someone help me on this ?

Hi,
I have to fetch Emp details (emp code, last name, first name ...etc) from a WSDL.
for this i have created HTTP connection -> created Web Service Task -> created XML Tasks for those emp code, last name, first name ... etc for each -> set a
breakpoint over post execution -> verified & found that the variables are blank though my
results variable has some XML data generated.
please see some screenshots as below & suggest me how to get is succeed & put the values in database table:

Thanks a lot in advance !!! :)
best regards,
Venkat

Web Service Task in SSIS 2012

Hello,
I have a web service task that worked fine prior to upgrading from SQL Server 2005, but in 2012 fails with an error saying the "wsdl file is invalid". I am using the same wsdl file as I was using in 2005. Connectivity tests for the
web service connection manager in 2012 worked fine. Any ideas on why I would be getting a failed wsdl file when it worked ok on the 2005 platform? Below is the specific error:
[Web Service Task] Error: An error occurred with the following error message: "Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebserviceTaskException: Could not read the Web Services Description Language (WSDL) file. The input WSDL file is not valid.
The following error occurred while reading the file. There is an error in XML document (3, 2)..
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebServiceTaskUtil..ctor(Object connection, String downloadedWSDL)
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebServiceTask.executeThread()".
Thanks for any help or suggestions,
Pat

Need to open the package for editing and resave, perhaps there were changes in how the Web Services task is persisted to package file. (a more typical upgrade path is SSIS 2005 to SSIS 2008, then 2012)
Arthur My Blog

Scalable Apache service in a zone cluster

Hi,
I have set up a 2-virtual node zone cluster (on a physical 2-node cluster).
I am trying to set up an apache resource group (scalable) on the two nodes, but I don't get the zone cluster nodes as valid options to use while running clsetup and/or the web gui wizard.
They only see the two global zones and one failover zone I have configured on the cluster.
Is there no way to set up a scalable apache service on the zone cluster? Any help will be appreciated.
Thanks,
D

Never mind...I had to run the clrg,clrs and clressharedaddress commands from within the zone cluster nodes and not from the global.
It's going to take a while to come to terms with the clustering within the cluster.
:)

Web Service Task Error

Hi, After successfully testing connection to my source web service, while executing my web service task, I face the following error. Can anyone help me????
[Web Service Task] Error: An error occurred with the following error message: "Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebserviceTaskException: Could not load the proxy for the specified Web service. The error is: Could not load file or assembly
'iiglotg3.dll' or one of its dependencies. Access is denied..
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebMethodInvokerProxy.loadProxyInAppDomain()
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebMethodInvokerProxy.InvokeMethod(DTSWebMethodInfo methodInfo, String serviceName, Object connection)
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebServiceTaskUtil.Invoke(DTSWebMethodInfo methodInfo, String serviceName, Object connection, VariableDispenser taskVariableDispenser)
at Microsoft.SqlServer.Dts.Tasks.WebServiceTask.WebServiceTask.executeThread()".
Regards,
Njdeh Tahmasian

Could not load file or assembly 'iiglotg3.dll' or one of its dependencies.
Access is denied..
Looks like a permission issue or maybe the assembly don't exists on the server where the package is running; you should check that first.
Olaf Helper
[ Blog] [ Xing] [ MVP]

Singleton service/task in a cluster

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