created 2025-04-16, & modified, =this.modified
Computing Cluster
A computing cluster is a set of computers that work together, so as to be viewed as a single system. Cloud computing is a form of computing clusters.
The history of early computer clusters is more or less directly tied to the history of early networks, as one of the primary motivations for the development of a network was to link computing resources, creating a de facto computer cluster.
When a node in a cluster fails, strategies such as fencing may be employed to keep the rest of the system operational. Fencing is the process of isolating a node or protecting shared resources when a node appears to be malfunctioning. There are two classes of response
- disabling the node itself
- allowing access to node resources such as shared disk
Fencing is required because it is impossible to distinguish between a real failure and a temporary hang. If the malfunctioning node is really down, then it cannot do any damage, so theoretically no action would be required (it could simply be brought back into the cluster with the usual join process). However, because there is a possibility that a malfunctioning node could itself consider the rest of the cluster to be the one that is malfunctioning, a split brain condition could ensue, and cause data corruption. Instead, the system has to assume the worst scenario and always fence in case of problems.
Beowulf Cluster
A beowulf cluster is a computing cluster of identical, commodity grade computers that are networked into one high performance parallel computing cluster. The name comes from the Old English epic poem, Beowulf.
The server node controls the cluster and serves messages to the clients.