Dokku does this. You either deploy from command line or something like a GitHub action (or CI). Container 1 and 2 are briefly running concurrently, and networ

Dokku does this. You either deploy from command line or something like a GitHub action (or CI). Container 1 and 2 are briefly running concurrently, and networking is updated to point to the new container once it finishes its build phase, and passes any pre-defined tests (or after 10 seconds of running without crashing).