Docker

Solution: Intermodal Shipping Container

Intermodal Shipping Container

Solution: Why It Works: Separation of Concerns

The introduction of Docker helped in the eliminating of this matrix, by isolating the worries of developers and administrators. Developers can focus on bundling applications and dependencies as containers, without agonizing over underlying hardware/infrastructure. Administrators/DevOps team can concentrate on managing containers, without agonizing over the contents of those containers.

Separation of Concerns

Solution: Benefits for Developers & Administrators

What is Docker?

Docker is an open platform for developing, shipping & running distributed applications, whether on laptops, data center VMs or cloud. Docker provides the ability to package and run an application in a loosely isolated environment called a container. The Docker Platform consists of multiple product/tools, including the Docker Engine, Images, Containers, and Hub, among others.

The Docker platform is the only container platform to build, secure and manage the widest array of applications from development to production both on premises and in the cloud.

Docker Architecture

Docker Architecture

Docker Images, Containers & Registries

Images Containers Registries
An image is a static representation of the app or service and its configuration and dependencies. Container is runtime object or representation of an image. An image is a static representation of the app or service and its configuration and dependencies
An image is an instance of a container.  When an image is started, it gives running container of an image. Containers are lightweight & portable encapsulation of  an environment where applications are run A Docker image is built up from a series of layers 
A Docker image is built up from a series of layers, allowing a minimal amount of data to be sent when transferring images over network. Command – “docker ps” only outputs running containers Images are stored in a registry 
Images are stored in a registry such as docker hub When a docker image is run using command “docker run” it creates a container from that instance.
Images are created with the “build“ command Containers can be run in either active or detached mode.
Local images can be listed by running command – docker images Filesystem changes made in a container do not affect the image

VM vs. Containers

VM vs Containers

Toufiq Mahmud