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Posts Tagged ‘Rene van Wijk’

WebLogic Server on Linux 7 by René van Wijk

Posted: June 13, 2015 in WebLogic
Tags: Jürgen Kress, Linux, opn, oracle, Rene van Wijk, weblogic, weblogic community

In this post, we will set-up a WebLogic Server environment on Linux 7 hosts; Show how to create systemd unit files for the Node Manager and the Apache HTTP Server (that contains the WebLogic Server Proxy Plug-In); See how automation tools, such as Ansible, can be made operating system version aware such that the same configuration can be used for multiple operating system distributions; Finally, we will test the environment.
And yes, WebLogic Server is supported on Linux 7 – just take a look at the certification matrix. Here, we see that WebLogic 12.1.3 with Oracle JDK 1.8.0_20+ is certified on Linux 7 (Oracle Linux 7 and Red Hat Enterprise Linux 7).

Creating virtual machines

The steps to create a virtual machine are as follows

Open VMWare WorkStation and click file, new virtual machine.
Choose custom and click next.
Choose a certain virtual machine hardware compatibility. In this case we choose Workstation 11.0. Click next.
Choose I will install the operating system later. Click next.
Select the guest operating system. In this case we choose Linux and set the version to CentOS 64-bit.
Click next and enter the following parameters:
- virtual machine name: machine1dotcom
- location: C:\temp\VirtualMachines\machine1dotcom
Click next.
Choose the number of processors, for example one processor with four cores, and click next.
Configure the amount of memory for the virtual machine, for example 4096MB, and click next.
Select the network type, for example network address translation (NAT), and click next.
Select the I/O controller type (choose the recommended type) and click next.
Select the virtual disk type (choose the recommended type) and click next.
Select create a new virtual disk and click next. This article provides information on increasing the size of a virtual disk. This procedure is necessary to accommodate data requirements that have changed since the creation of the virtual disk.
Enter the disk capacity, for example 20GB, select split virtual disk into multiple files and click next.
Enter the name for the disk file and click next.
Click finish
After the virtual machine is created click edit virtual machine settings

Read the complete article here.

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Technorati Tags: Rene van Wijk,Linux,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

Coherence, WebLogic and Java SE 8 by René van Wijk

Posted: April 2, 2015 in WebLogic
Tags: Coherence, Jürgen Kress, opn, oracle, Rene van Wijk, weblogic, weblogic community

In this post we will explore some new Java SE 8 features,

Lambda Expressions enable us to treat functionality as a method argument, or code as data. Lambda expressions let us express instances of single-method interfaces (referred to as functional interfaces) more compactly. The Java SE 8 API also ships a lot of new functional interfaces to make our life easier.
Method references provide easy-to-read lambda expressions for methods that already have a name.
Default methods enable new functionality to be added to the interfaces of libraries and ensure binary compatibility with code written for older versions of those interfaces.
Classes in the new java.util.stream package provide a Stream API to support functional-style operations on streams of elements. The Stream API is integrated into the Collections API, which enables bulk operations on collections, such as sequential or parallel map-reduce transformations.

and see how these work out on WebLogic and Coherence. Note that WebLogic 12.1.3 and Coherence 12.1.3 are supported on Java SE 8, with the following restrictions:

WebLogic Server 12.1.3 does not support applications using the Java SE 8 fork/join and parallel streams features. Avoid these features when building WebLogic Server 12.1.3 applications using Java SE 8. The reason for this restriction is that the threads used by the fork/join thread pool will not be WebLogic Server managed threads. Any of the work performed in these threads may not be able to make use of WebLogic Server or Java EE facilities because the state of these threads, including security and transaction state, may not be created properly. Further, these threads will not be controlled by WebLogic Server Work Manager thread management facilities, possibly resulting in excessive thread usage.
When using Java SE 8, the use of permgen-memory is no longer required. The Java command line options -XX:PermSize and -XX:MaxPermSize are ignored: Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0.
Java SE 8 has new APIs for JDBC 4.2 and is supported for WebLogic Server 12.1.3 running on Java SE 8 with a JDBC driver that supports JDBC 4.2. However, although the Oracle JDBC thin driver bundled with WebLogic Server is certified on Java SE 8, the Oracle JDBC thin driver does not support JDBC 4.2.
When running using SSL connections with JCE on JDK 8, it may be necessary to install the Java Cryptography Extension Unlimited Strength Jurisdiction Policy Files 8.

As an example, we will use the application presented in the post Coherence 12c Grid Archive. To include some Java SE 8 features, we rewrite the servlet as (in which we also use parallel streams, although not supported, but just out of curiosity to see what goes on in the Java runtime). Read the complete article here.

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Whole Server Migration by Rene van Wijk

Posted: December 4, 2014 in WebLogic
Tags: Jürgen Kress, opn, oracle, Rene van Wijk, server migration, weblogic, weblogic community

In a WebLogic Server cluster, most services are deployed homogeneously on all server instances in the cluster, enabling transparent fail-over from one server instance to another. In contrast, for ‘pinned services’ such as JMS and the JTA transaction recovery system are targeted at individual server instances within a cluster, WebLogic Server supports failure recovery with migration, as opposed to fail-over.
Migration in WebLogic Server is the process of moving a clustered WebLogic Server instance or a component running on a clustered server instance elsewhere in the event of failure. Upon failure, a migratable server is automatically restarted on the same machine, if possible. If the migratable server cannot be restarted on the machine where it failed, it is migrated to another machine. In addition, an administrator can manually initiate migration of a server instance.

Configure whole server migration

Before we configure whole server migration, we need to know the requirements:

The migratable server candidate machines have to be in the same subnet (because the virtual IP address must be valid on each candidate machine). Whole server migration uses a virtual IP address for each migratable server.
On each candidate machine, the Node Manager must be initialized such that it can accept commands from the Admin Server.
The Node Manager is used to migrate the virtual IP address and assign it to the target machine (i.e., invoke ${DOMAIN_HOME}/bin/server_migration/wlsifconfig.sh addif or invoke ${DOMAIN_HOME}/bin/server_migration/wlsifconfig.sh removeif). Note that the default configuration assumes that the machines are similar, i.e.,
- The netmask associated with the virtual IP is the same on each candidate machine.
- The network device (interface) name (for example, eth0 on Linux) is the same on each candidate machine.
- The functional behavior of the platform-specific OS command used to add and remove the virtual IP (for example, ifconfig and arping on Linux) is the same.
Migratable servers cannot define any network channels that use a Listen Address different from the virtual IP address associated with the server. If servers must use multiple network channels associated with multiple IP addresses, whole server migration cannot be used as only migration of a single virtual IP address for each migratable server is supported.
Server-specific state must be shared through some highly available sharing mechanism, i.e., the default persistent stores where the XA transaction logs are kept must be accessible on each candidate machine.

As mentioned above the Node Manager invokes the script wlsifconfig.sh to run ifconfig and arping commands (more information on these commands can be found here), for example, Read the complete article here.

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Middleware Snippets Rene van Wijk

Posted: May 9, 2014 in Uncategorized
Tags: Jürgen Kress, opn, oracle, Rene van Wijk, weblogic, weblogic community

Thanks to Rene for the nice updated blog! “A blog that mediates between an application program and a network.” The blog is dedicated to the latest information for WebLogic & application server technologies, make sure you visit it regular! Some of the latest articles include:

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Automatic Scaling an Application using WebLogic by René van Wijk

Posted: February 26, 2014 in Uncategorized
Tags: Jürgen Kress, opn, oracle, Rene van Wijk, scaling, weblogic, weblogic community

Say we want to add (or start) managed server instances when running an application, for example, when the number of open sessions reach a certain value. For this value we have calculated that the memory consumption is beyond a level, such that the garbage collection is affected. By adding (or starting) a new server we balance the load (the number of sessions with its corresponding memory consumption) across multiple servers. By using the WebLogic Diagnostic Framework, we can collect the metrics we need and create a watch for that metric with a corresponding notification. By using this notification we can then further create the logic needed in order to add (or start) a managed server. For example, by using the notification service that come with the WebLogic Diagnostic Framework we can send a JMS message or a JMX notification. In this post we are going to use the JMS approach. Environment The WebLogic environment consists of a cluster, spanning two machines, and consisting of four managed servers. This can be easily set-up by using the scripts presented in the post Automate WebLogic 12.1.2 Deployment. The diagnostic module is configured as follows – See more at: Read the complete article here.