Posted By: Anonymous
Is it possible to run Windows Containers on Linux? The scenario is based on an app written in the .NET (old net) and the Linux user that wants to run this with Docker to provide a
net462 written API on the
I am using beta version from Docker Desktop for Windows
If no, then why can Windows run Linux containers and not vice-versa?
As some time has passed and this question is a popular one. I’d like to add one note here that the workaround is to use the new netstandard. It allowed me to pack
4.6.2 framework into new library.
Some of the comments says that the answer is not clear, I’ll try to clarify.
Q: Can Windows containers run on Linux?
A: No. They cannot.
Containers are using the underlying Operating System resources and drivers, so Windows containers can run on Windows only, and Linux containers can run on Linux only.
Q: But what about Docker for Windows? Or other VM-based solutions?
A: Docker for Windows allows you to simulate running Linux containers on Windows, but under the hood a Linux VM is created, so still Linux containers are running on Linux, and Windows containers are running on Windows.
Bonus: Read this very nice article about running Linux docker containers on Windows.
Q: So, what should I do with a .Net Framework 462 app, if I would like to run in a container?
A: It depends. Following several recommendations:
- If it is possible – move to .Net Core. Since .Net Core brings support to most major features of .Net Framework, and .Net Framework 4.8 will be the last version of .Net framework
If you cannot migrate to .Net Core – As @Sebastian mentioned – you can convert your libraries to .Net Standard, and have 2 versions of app – one on .Net Framework 4.6.2, and one on .Net Core – it is not always obvious, Visual Studio supports it pretty well (with multi-targeting), but some dependencies can require extra care.
(Less recommended) In some cases, you can run windows containers. Windows containers are becoming more and more mature, with better support in platforms like Kubernetes. But to be able to run .Net Framework code, you still need to run on base image of “Server Core”, which occupies about 1.4 GB. In same rare cases, you can migrate your code to .Net Core, but still run on Windows Nano servers, with an image size of 95 MB.
Leaving also the old updates for history
If you are using Docker-for-Windows, you can run now both windows and linux containers simultaneously: https://blogs.msdn.microsoft.com/premier_developer/2018/04/20/running-docker-windows-and-linux-containers-simultaneously/
Bonus: Not directly related to the question, but you can now run not only the linux container itself, but also orchestrator like kubernetes: https://blog.docker.com/2018/07/kubernetes-is-now-available-in-docker-desktop-stable-channel/
Updated at 2018:
From this post:
Doesn’t Docker for Windows already run Linux containers? That’s right.
Docker for Windows can run Linux or Windows containers, with support
for Linux containers via a Hyper-V Moby Linux VM (as of Docker for
Windows 17.10 this VM is based on LinuxKit).
The setup for running Linux containers with LCOW is a lot simpler than
the previous architecture where a Hyper-V Linux VM runs a Linux Docker
daemon, along with all your containers. With LCOW, the Docker daemon
runs as a Windows process (same as when running Docker Windows
containers), and every time you start a Linux container Docker
launches a minimal Hyper-V hypervisor running a VM with a Linux
kernel, runc and the container processes running on top.
Because there’s only one Docker daemon, and because that daemon now
runs on Windows, it will soon be possible to run Windows and Linux
Docker containers side-by-side, in the same networking namespace. This
will unlock a lot of exciting development and production scenarios for
Docker users on Windows.
As mentioned in comments by @PanagiotisKanavos, containers are not for virtualization, and they are using the resources of the host machine. As a result, for now windows container cannot run “as-is” on linux machine.
But – you can do it by using VM – as it works on windows. You can install windows VM on your linux host, which will allow to run windows containers.
With it, IMHO run it this way on PROD environment will not be the best idea.
Also, this answer provides more details.