We've now covered how to open our containers to the external world - we can use networking and mounted volumes to be able to share data between containers and other hosts. Let's summarize what we have learned so far in this chapter. We know that containers from the same Docker host see each other automatically on the default bridge network, only if the container is bound to default bridge. We can make containers running on different hosts to communicate with each other. To do this, we need a multi-host overlay network. You will need Docker version 1.12 or later running in swarm mode, or alternatively, a key-value storage running. If the drivers provided by Docker are not enough, we can use the network plugins to further extend the networking data exchange. We went through the volume creation process and know that volumes persist data even through container restarts; we also know that changes to files on the volume are made directly, but they will not be included when you update an...