How do you plan to implement ALL networking components and features of mailcow in ECS? How do you plan to implement the netfilter? How would you run multiple instances of services, that need to be configured as cluster, if started multiple times?
People are so stuck with the terms “cluster”, “orchestration” and “containers” nowadays. Only a few seem to understand the downsides like new SPOFs, networking, maintenance and other hassles. Those to have worked with k8s/ecs know exactly what a pain it is. You cannot start an app or a container 2x and have a cluster.
It is possible to run master/master replicated, but that’s not documented. It is not part of the Open-Source documentation.