Understanding Docker Containers

Docker is an open source project, primarily run by a company of the same name, that provides features similar to Microsoft application virtualization (App-V) but for server applications. The technology was created to help organizations distribute applications and the components they require across multiple servers in a reliable and reproducible way, with less overhead and faster deployment than deploying on VMs. Web applications, like the WordPress publishing platform, are ideal candidates for Docker-based deployment.

To use Docker containers, developers first create Docker image files that contain the applications and any dependencies. These read-only images are stored in a Docker registry (unrelated to the Windows Registry). A command-line-based client residing on each target server (referred to as a Docker host) retrieves images from the registry when the containers are deployed. Distributing applications as images provides a consistent starting point for developers, testers, or administrators to deploy and update applications, as compared to complex installation scripts or installers with multiple steps that are required with VMs. Once deployed on a Docker host, an application packaged within an image can be run as a container.