I have had the opportunity to write a blog for Apress with a brief introduction to MySQL NDB Cluster. The blog gives a brief overview of the history and why you should consider it. The architecture is described before some key characteristics are discussed.
If you are interested, the blog can be found at https://www.apress.com/us/blog/all-blog-posts/what-is-mysql-ndb-cluster/15454530.
Over view of the MySQL NDB Cluster architecture.