Docker, a Hyper-V container, or a Windows Container?

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Man this test prep is killing me.... Apologies for all the posts lately!! Hopefully I am helping others out there with some clarifying points.. Things have sure changed since my MCSE 2003 exams back in 2006.. :(

Anyhoo, I ran into a practice question that talks about deploying IIS in a "Windows Container". It says that you need to "prepare" the server for the planned deployment. There is then a pick list of the following steps and you are supposed to select three in sequence.

Install the Hyper-V server role.
Install the Base Container Images.
Install the Container feature.
Install the Web Server role
Install Docker.

As I was researching I ran across this article:
https://docs.microsoft.com/en-us/virtualization/windowscontainers/deploy-containers/deploy-containers-on-server

This lays out how to get started pretty clearly, but I still don't understand the difference between "Docker", a "Hyper-V container", and a "Windows Container". When would you use one vs another?

Regards,
Adam Tyler

@adam-tyler said in Docker, a Hyper-V container, or a Windows Container?:

Man this test prep is killing me.... Apologies for all the posts lately!! Hopefully I am helping others out there with some clarifying points.. Things have sure changed since my MCSE 2003 exams back in 2006.. :(

This change is about to be even more so as new iterations of Microsoft Certs are coming out in 2019

This lays out how to get started pretty clearly, but I still don't understand the difference between "Docker", a "Hyper-V container", and a "Windows Container". When would you use one vs another?

As always, context is the key is understanding the difference

• Docker containers essentially provide that native linux environment for applications to run the way they need to run, regardless what system they may be deployed to. But Docker within Windows runs in a full Linux VM or with Hyper-V Isolation (LCOW).
• Windows Containers are approximately the same as Docker but for Windows environments. They are isolated in the same way as docker (through namespace, resource access and control and process isolation).
• Hyper-V containers are run within special VMs. They provide kernel level isolation.

So the reason to run one or the other is really depended upon the applications that are needed.

Thank you Ronnie, am I correct in assuming that both the Docker container and Windows Containers share CPU and memory with the host OS? Unlike a Hyper-V container where you would allocate virtual CPUs and memory to the VM? In each demo I've watched it seems like Docker containers simply use as much CPU memory as they need. There really isn't a separate setting like there is with a full Hyper-V container and kernel isolation.

When would you choose to use a Hyper-V container over a Windows Container? Can a Hyper-V container run Windows or Linux?

Regards,
Adam Tyler

@adam-tyler,

Containers on Windows behave a bit different than on Linux. So, I believe probably the best way to think about it is that in Windows it's a virtualized application rather than need what a traditional vm needs. In the background it's still using the built in Hyper-V functionality, even on Windows 10, you'll see that it will require you to install the hyper-v feature then reboot and now your desktop is essentially running as a VM on the Hyper-V Hypervisor.

The context is probably about the functionality needed:

• if you need kernel level isolation, then Hyper-V containers are really specialized isolated VMs.
• If you do not need kernel level isolation, then Windows containers are isolated through namespace, remote access and control and process isolation but not kernel level

Thank you Ronnie, that helps.

Regards,
Adam Tyler