Docker

Full Title or Meme

Docker is a system for building, deploying and running complex images of a program with its runtime.

Context

• With the rise of cloud computing the need arose to give users an easy way to create a run-time package that could be sent to any cloud Platform as a Service provider (PaaS) with complete interoperability.

Solutions

Docker was released in 2013 and solved many of the problems that developers had running containers end-to-end. It had all these things:

1. A container image format
2. A method for building container images (Dockerfile/docker build)
3. A way to manage container images (docker images, docker rm , etc.)
4. A way to manage instances of containers (docker ps, docker rm , etc.)
5. A way to share container images (docker push/pull)
6. A way to run containers (docker run)

Open Container Initiative

• Open Container Initiative (OCI)
• OCI runtime specification.
• Google code for running containers as a tool and library called runc

When you run a Docker container, these are the steps Docker actually goes through:

1. Download the image
2. Unpack the image into a "bundle". This flattens the layers into a single filesystem.
3. Run the container from the bundle