An open-source project for automating the deployment of applications as portable, self-sufficient containers that can run virtually anywhere on any type of server. Docker serves as a lightweight alternative to full machine virtualization provided by traditional hypervisors like VMware’s ESXi, Xen or KVM.
With a traditional hypervisor approach, each virtual machine (VM) needs its own operating system, but with Docker, applications operate inside a container that resides on a single host operating system that can serve many different containers.
Docker containers are designed to run on everything from physical computers to virtual machines, bare-metal servers, OpenStack cloud clusters, public instances and more. Docker extends the LinuX Containers (LXC) format, which serves to provide an isolated environment for applications, by enabling image management and deployment services.
Docker debuted in March 2013. Docker support is being integrated with the OpenStack cloud platform, and at the time of announcement, Red Hat pledged to include Docker in the Red Hat Enterprise Linux 7 (RHEL 7) release.