It’s not immediately obvious to me how this differs from something like ansible which people have been using for years for basic deployment topologies. What am I missing?

edit: after looking a bit closer, I think it’s a bit misleading to call what this is doing “zero downtime”. as far as I can tell, your services are essentially going to be unresponsive until they start, which can be brutal for slow starting ones (and that’s assuming they start successfully)