The biggest challenges have been in cross-container communications
 

The biggest challenges have been in cross-container communications

There have always been container networking issues. Containers hosted on the same physical server can interact with one another and share data. But Docker developers didn’t initially build in the ability to migrate a container from one host to another, or connect one container to another on a different host.

The biggest challenges have been in cross-container communications. “From one container to another, that’s the biggest frustration that most networking professionals will encounter.”
Engineers at Docker, the company that develops the open source project of the same name, quickly realized they needed to fix this.