I am currently building a SMALLER beowulf cluster (smaller than 16 nodes) and need help ditirmining a operating system for the main node.

I tried UBUNTU on the machine being used as the main, however, it failed, and i was wondering what other versions of linux would be SUFFICIENT in running a cluster.

Any help appreciated, and if you have any questions, please do ask. I don't know anything.
Here is a refer for the benefit of others.

Beowulf cluster
From Wikipedia, the free encyclopedia
Quote

A Beowulf cluster is a computer cluster of what are normally identical, commodity-grade computers networked into a small local area network with libraries and programs installed which allow processing to be shared ...
... name comes from the main character in the Old English epic poem Beowulf, which was bestowed by Sterling because the titular hero is described as having "thirty mens' heft of grasp in the grip of his hand".
... no particular piece of software that defines a cluster as a Beowulf. Beowulf clusters normally run a Unix-like operating system, such as BSD, Linux, or Solaris, normally built from free and open source software. Commonly used parallel processing libraries include Message Passing Interface (MPI) and Parallel Virtual Machine (PVM). ...
Currently there are a number of Linux distributions, and at least one BSD, that are designed for building Beowulf clusters. These include:
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ClusterKnoppix, based on Knoppix
Kerrighed
Rocks Cluster Distribution
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DragonFly BSD
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A cluster can be set up by using Knoppix bootable CDs in combination with OpenMosix. The computers will automatically link together, without need for complex configurations, to form a Beowulf cluster using all CPUs and RAM in the cluster.
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Beowulf systems are now deployed worldwide, chiefly in SUPPORT of scientific computing.