I fail to see how implementing the ambassador pattern would help us simplify / modularize the design of our container architecture.
Let's say that I have a database container db on host A and is used by a program db-client which sits on host B, which are connected via ambassador containers db-ambassador and db-foreign-ambassador over a network:
[host A (db) --> (db-ambassador)] <- ... -> [host B (db-forgn-ambsdr) --> (db-client)] Connections between containers in the same machine, e.g. db to db-ambassador, and db-foreign-ambassador to db-client are done via Docker's --link parameter while db-ambassador and db-foreign-ambassador talks over the network.
But , --link is just a fancy way of inserting ip addresses, ports and other info from one container to another. When a container fails, the other container which is linked to it does not get notified, nor will it know the new IP address of the crashing container when it restarts. In short, if a container which is linked to another went dead, the link is also dead.
To consider my example, lets say that db crashed and restarts, thus get assigned to a different IP. db-ambassador would have to be restarted too, in order to update the link between them... Except you shouldn't. If db-ambassador is restarted, the IP would have changed too, and foreign-db-ambassador won't know where to reach it at the new IP address.
Read full article from Failing to see how ambassador pattern enhances modularity / simplicty of container architecture in Docker - Stack Overflow
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