Question

When would you choose to use containers in Windows and when would you choose to use containers in Linux? How are they different? How are they similar?

Answer 1

Use containers in Windows :

• Maintaining parity between testing and production

For software developers and testers, ensuring that the conditions under which you write and test an application are the same as those under which it is deployed into production is an age-old challenge.

Containers help to address this problem because they package configuration variables inside the container environment. As a result, conditions on the host server don't impact the way a containerized application behaves, at least in general.

• Running different versions of the same application

But with containers, it becomes easy to have different versions of the same application running side-by-side, without making a mess. You simply package each application into a container and run it.

• Using the same toolset on Windows and Linux

Maybe your organization has both Windows and Linux servers. In that case, Docker can come in handy as a way to standardize your toolset for deploying application.

• Security

You can optionally run containers on Windows in what Microsoft calls "Hyper-V mode." With this approach, each container runs inside a Hyper-V virtual machine instance.

Use containers in Linux :

Undoubtedly, one of the biggest reasons for recent interest in container technology has been the Docker open source project, a command line tool that made creating and working with containers easy for developers and sysadmins alike, similar to the way Vagrant made it easier for developers to explore virtual machines easily.

Docker is a command-line tool for programmatically defining the contents of a Linux container in code, which can then be versioned, reproduced, shared, and modified easily just as if it were the source code to a program.

Containers have also sparked an interest in microservice architecture, a design pattern for developing applications in which complex applications are broken down into smaller, composable pieces which work together. Each component is developed separately, and the application is then simply the sum of its constituent components. Each piece, or service, can live inside of a container, and can be scaled independently of the rest of the application as the need arises.

• Similarities

Docker containers on Linux and Windows are similar in the following ways:

• They are designed to function as application containers.
• They run natively, meaning they do not depend on hypervisors or virtual machines.
• They can be administered through Docker (although you can also use PowerShell to manage containers on Windows).
• They are limited to containing applications that are natively supported by the host operating system. In other words, Docker for Windows can only host Windows applications inside Docker containers, and Docker on Linux supports only Linux apps.
• They provide the same portability and modularity features on both operating systems.

Differences:

• Docker supports only certain versions of Windows (namely, Windows Server 2016 and Windows 10). In contrast, Docker can run on any type of modern Linux-based operating system.
• Even on Windows versions that are supported by Docker, Windows has stricter requirements regarding image compatibility. Read more about those here.
• Some Docker networking features for containers are not yet supported on Windows. They are detailed at the bottom of this page.
• Most of the container orchestration systems that are used for Docker on Linux are not supported on Windows. The exception is Docker Swarm, which is supported. (If you want to use a different orchestrator on Windows, however, fret not; Windows support for orchestrators such as Kubernetes and Apache Mesos is under development.)