Docker is an open platform for developers and sysadmins to build, ship, and run distributed applications, whether on laptops, data center VMs, or the cloud.
Containers
Containers are isolated, but share OS
and, where appropriate, bins/libraries
Docker Images
Why so popular?
It can get more applications running on the same hardware than other technologies.
It makes it easy for developers to quickly create ready-to-run containered applications.
It makes managing and deploying applications much easier.
Docker 1.0 released in June 2014
10% of enterprises currently* use containers in production now, but up to a third are testing them.
*According to Forrester analyst Dave Bartoletti on May 2017
Docker
Virtual Machines
vs
VM are "based on emulating virtual hardware. That means they're fat in terms of system requirements.
Containers, however, use shared operating systems.
You can have as many as four-to-six times the number of server application instances as you can using VMs on the same hardware.
