6.1 Why OSCAR?

The design goals for OSCAR include using the best-of-class software, eliminating the downloading, installation, and configuration of individual components, and moving toward the standardization of clusters. OSCAR, it is said, reduces the need for expertise in setting up a cluster. In practice, it might be more fitting to say that OSCAR delays the need for expertise and allows you to create a fully functional cluster before mastering all the skills you will eventually need. In the long run, you will want to master those packages in OSCAR that you come to rely on. OSCAR makes it very easy to experiment with packages and dramatically lowers the barrier to getting started.

OSCAR was created and is maintained by the Open Cluster Group (http://www.openclustergroup.org), an informal group dedicated to simplifying the installation and use of clusters and broadening their use. Over the years, a number of organizations and companies have supported the Open Cluster Group, including Dell, IBM, Intel, NCSA, and ORNL, to mention only a few.

OSCAR is designed with high-performance computing in mind. Basically, it is designed to be used with an asymmetric cluster (see Chapter 1). Unless you customize the installation, the computer nodes are meant to be dedicated to the cluster. Typically, you do not log directly onto the client nodes but rather work from the head node. (Although OSCAR sets up SSH so that you can log onto clients without a password, this is done primarily to simplify using the cluster software.)

While identical hardware isn't an absolute requirement, installing and managing an OSCAR cluster is much simpler when identical hardware is used.

Actually, OSCAR could be used for any cluster application-not just high-performance computing. (A recently created subgroup, HA-OSCAR, is starting to look into high-availability clusters.) While OSCAR installs a number of packages specific to high-performance computing by default which would be of little use for some other cluster uses, e.g., MPI and PVM, it is easy to skip the installation of these packages. It is very easy to include additional RPM packages to an OSCAR installation. Although OSCAR does not provide a simple mechanism to do a post-installation configuration for such packages, you can certainly include configuration scripts if you create your own packages. There is a HOWTO on the OSCAR web site that describes how to create custom packages. Generally, this will be easier than manually configuring added packages after the installation. (However, by using the C3 tool set included in OSCAR, many post-install configuration tasks shouldn't be too difficult.)

Because of the difficulty in bringing together a wide variety of software and because the individual software packages are constantly being updated, some of the software included in OSCAR has not always been the most current versions available. In practice, this is not a problem. The software OSCAR includes is stable and should meet most of your needs.

While OSCAR was originally created using Red Hat Linux, a goal of the project is to move beyond support for a single distribution and Mandrake Linux is now also supported. The OSCAR project has shifted to SIS in order to eventually support most RPM-based versions of Linux. But don't expect support for the latest Linux versions to be immediately available as the new versions are released.