VisualVM is a useful tool for monitoring and simple profiling of JVM processes. It integrates various command line tools of the JDK such as jstat, jinfo, jstack into a graphical UI. The tool is part of the JDK since 1.6.0_07.
The first post of this series focused on the basic concepts behind clustering JBoss AS 7 and EAP 6. We explained how to enable cluster capabilities for a simple Java EE application and setup a basic cluster environment in the standalone operation mode. In this post we will now explain the domain mode and how to manage a cluster environment in managed domains.
A managed domain spans over multiple hosts with centralized administration and management policies. Each host that runs in domain mode can contain several server instances that belong to one domain. The domain mode is one of two possible operating modes of the EAP 6 respectively the JBoss AS 7. The other mode is the standalone mode. A JBoss application server, which operates in the standalone mode, is an independent process. This mode is pretty similar to the previous versions of the JBoss application server. The different operating modes have no influence to the capabilities of the application server, but rather how to manage one or multiple servers. So, the domain mode is completely independent from clustering. But it provides many useful features for managing clustered environments such as handling of deployments for multiple instances. For example the JBoss AS 7 running in standalone mode does not support any more the previous farming deployment capabilities. Now, this can be done with the domain mode capabilities and of course there are more features such as starting and stopping servers from one single console that makes it easier to handle clustered environments.
The ability to combine different servers to a cluster that hides its internal servers from the clients and offers a virtual platform for an application is important for enterprise applications. It can be used to provide
- high scalability by adding cheap computational resources to the cluster on demand or
- high availability by using a transparent failover that hides faults within single servers.
Usually high scalability limits high availability and vice versa, but it is also possible to get both. The JBoss application server can be configured to support both features.
This post is the first one of a series about clustering with the JBoss AS 7. Here, we focus on the basic concepts behind JBoss AS 7 clustering and show you how to setup a basic clustered environment with a simple Java EE application.
In the series, we concentrate on the JBoss AS 7 respectively the EAP 6, which is the Red Hat-supported version of the JBoss application server. Future posts will be about particular subsystems of the JBoss AS, such as HornetQ or Infinispan.
After more than two years of development and one year after the release of the first community version, yesterday the JBoss Enterprise Application Platform 6.0.0 (EAP6) was published at the Red Hat customer portal. It is built around the new blazingly fast und thoroughly modular JBoss application server 7. It supports the full Java EE 6 profile and it is the first EAP version that provides a downloadable Maven repository. By adding it to your enterprise repository you can enjoy the same benefits for the development as with the community version.
The EAP 6.0.0 is built from the 7.1.2 development branch of the JBoss application server. The development of the community version switched to the 7.2.0 branch. Thus, the EAP will be continuously hardened for enterprise production environments whereas the community version will stay the focus for innovation.
The EAP 6.0.0 is available with a subscription from Red Hat. The subscription includes enterprise-class support SLAs, guaranteed patches, updates, hot-fixes, and legal assurance.
You can download a 30-days evaluation version of the EAP 6.0.0 from the Red Hat customer portal.
Since March 15th of the JBoss Enterprise Application Platform (EAP) is available in the Version 6 Beta. The EAP is based on the Java EE 6 certified JBoss AS 7.1 community release, which impresses not only by the fast start-up time and low memory consumption but also by its new clean architecture.
At the moment, the EAP 6 Beta is pretty close to the community version. It includes a few critical bug fixes and some brandings. The differences will be larger with the on going quality assurance and maintenance phase.