Terminology

The following terminology is often used when working with Cluster Director features.

Node or host
A single physical server machine in the data center. Each host has its associated compute resources such as accelerators. The number and configuration of these compute resources depend on the machine family. Virtual machine (VM) instances are provisioned on top of a physical host.

Sub-block
A group of hosts and associated connectivity hardware that are on a single rack.

Block
A collection of sub-blocks.

Cluster
A collection of blocks interconnected by a high-speed network fabric. Each cluster is globally unique. For A4X, A4, and A3 Ultra machines, a cluster provides a common, non-blocking network fabric for your blocks of accelerator capacity. Within a cluster, the east to west networking is non-blocking for the entire collection of blocks.

Dense deployment
A resource request that allocates your accelerator resources physically close to each other to minimize network hops and optimize for the lowest latency.

Network fabric
A network fabric provides high-bandwidth, low-latency connectivity across all blocks and Google Cloud services in a cluster. Jupiter is Google's data center network architecture that leverages software-defined networking and optical circuit switches to evolve the network and optimize its performance.