MySQL Fabric is a framework for managing groups of MySQL servers and using those servers to provide services. It is designed to be extensible so that over time many different services can be added. In the current version the services provided are high availability (built on top of MySQL replication) and scale-out (by sharding the data).
Fabric is implemented as a Fabric node/process (which performs management functions) and Fabric-aware connectors that are able to route queries and transactions directly to the most appropriate MySQL server. The Fabric node stores state and routing information in its state store (which is a MySQL database).
Before MySQL Fabric 1.6.x, Fabric was part of the MySQL Utilities. Fabric is now a standalone product that can be used with or without MySQL Utilities. Also, MySQL Fabric is no longer bundled with MySQL Utilities as of the 1.6.2 release.