The license comes with restrictions on what you can use your derivative works for - e.g. not creating an in-memory datastore service. It's essentially an Apache 2 with a "Also AWS can't just steal it and sell it as a service when it gets huge"
Is it open-source? Well, depending on your definition probably not. Is it a fair license? Yeah I'd think so.
Is it open-source? Well, depending on your definition probably not. Is it a fair license? Yeah I'd think so.