Unlike a virtual machine, a container does not need to boot the operating system kernel, so containers can be created in less than a second. This feature makes container-based virtualization unique and desirable than other virtualization approaches.

Not at all! Any data that your application writes to disk gets preserved in its container until you explicitly delete the container. The file system for the container persists even after the container halts.

Some of the largest server farms in the world today are based on containers. Large web deployments like Google and Twitter, and platform providers such as Heroku run on container technology, at a scale of hundreds of thousands or even millions of containers.

A container is a runtime instance of an image--what the image becomes in memory when executed (that is, an image with state, or a user process).

You can see a list of your running containers with the command, docker ps, just as you would in Linux.

You can use docker for
1. Fast, consistent delivery of your applications
2. Responsive deployment and scaling
3. Running more workloads on the same hardware

Docker containers do not package up the OS. They package up the applications with everything that the application needs to run. The engine is installed on top of the OS running on a host. Containers share the OS kernel allowing a single host to run multiple containers.

The best way for your team to get started is for your developers to download Docker for Mac or Docker Windows. These are native installations of Docker on a Mac or Windows device. From their, developers will take their applications and create a Dockerfile. The Dockerfile is where all of the application configuration is specified. It is essentially the blueprint for the Docker Image. The image is a snapshot of your application and is what the Docker Engine looks at so it knows what the container it is spinning up should look like.

Yes, Docker is an open platform for developing, shipping, and running applications.