Is the tikv key space feature available?

It’s very interesting. It provides an intuitive way to achieve data isolation.
Key space is mentioned in tikv api v2. As I tested with tiup, it’s actually not working. I wonder if this feature is only available after certain versions and/or it’s actually not fully released yet.

Yes, it does work to some extent but it’s not been used in production release of TiDB and there are many subtle configurations and client side code changes as prerequisites. Feel free to discover the way to use it by reading source code, you can definitely make it work.

Bear in mind that this feature is not officially supported and use it at your own risk. Good luck.