Zero-downtime deployments with Docker Swarm: What's the proper way?

[jaydrogers]

Thanks for getting back @cakiwi!

The intention of replicas: 1 was to minimize memory usage for simple apps (where they really don't need to be running multiple replicas).

Looking at the documentation (Compose file version 3 reference | Docker Documentation), it sounds like the services breifly overlap.

Questions

1. Does this mean replicas: 1 is the "hard cut-off", no matter the "update_config" setting?
2. If I set replicas: 2, just to confirm, I do not have to do anything with Traefik priority labels? It just does this automatically?

Thanks for your help!