What exactly is Ubuntu Core, and how does it relate to Ubuntu itself (i.e. the main desktop and server distribution)?
I've read the answer to this question, which says it's just a minimal install of Ubuntu, but it says nothing about the "snappy" transactional updates that Mark Shuttleworth mentioned in his blog post.
This is the brief explanation of Snappy on the main Ubuntu site: (source)
Ubuntu Core is a new rendition of Ubuntu for the cloud with transactional updates. Ubuntu Core is a minimal server image with the same libraries as today’s Ubuntu, but applications are provided through a simpler mechanism. The snappy approach is faster, more reliable, and lets us provide stronger security guarantees for apps and users — that’s why we call them “snappy” applications.
Snappy apps and Ubuntu Core itself can be upgraded atomically and rolled back if needed — a bulletproof approach to systems management that is perfect for container deployments. It’s called “transactional” or “image-based” systems management, and we’re delighted to make it available on every Ubuntu certified cloud.
