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I've read this article:

How is Docker different from a normal virtual machine?

I have huge intend of converting all my virtual images into docker instances.

I can't see an angle where vm still make sense...

So what's the point to VM now? Ok... maybe the desktop virtualization to have pulseaudio working?

Once docker solve this, what else?

UPDATE Okay... So I can't run docker in "non-linux" favour hosts...

Community
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stashfree
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  • No, the common workaround is boot2docker which runs a lightweigt Linux where docker runs. Normally this is for development only because in the cloud (deployment) Linux is the default anyway. Microsoft seems to be eager to provide a similar solution but so far I have only seen announcements. – Günter Zöchbauer Dec 20 '14 at 08:12
  • I really like docker's space efficiency when using btrfs / overlayfs / aufs... is it possible to achieve this with virtual machine? – stashfree Jan 03 '15 at 08:40

2 Answers2

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For one point you can't run an operating system within your container that is different from the OS on the host.

On Windows and Mac OSX boot2docker is used to run Docker which is VirtualBox running a reduced Linux OS which runs Docker.

Günter Zöchbauer
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The benefits of containers are clear and well known, but the disadvantages have been glossed over somewhat.

Specifically, you don't just need the same OS type (aka linux), you get the same version of the kernel (including any mods you want.) Since containers are an OS construct, there are resource islands per OS kernel version (and different implementations for Windows, BSD or any non-linux if they exist).

VM's are secured with CPU level isolation, containers are secured with OS level isolation (with arguably a bigger attack surface).

There are many claims out there that containers are as slow and as big as VM's once you load up your container with everything you need for production and add lots of overlays, but these are all anecdotal and no large scale survey or trustable data is available yet.

Michael Mullany
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