Technological advantages over Linux

[Paul Mather]

On Sat, 25 Jul 2020 13:55:42 +0700, Victor Sudakov <vas at sibptus.ru> wrote:

> Message: 14
> Date: Sat, 25 Jul 2020 13:55:42 +0700
> From: Victor Sudakov <vas at sibptus.ru>
> To: freebsd-questions at freebsd.org
> Subject: Re: Technological advantages over Linux
> Message-ID: <20200725065542.GG92589 at admin.sibptus.ru>
> Content-Type: text/plain; charset="us-ascii"
> 
> Dear Paul,
> 
> You have intrigued me.
> 
> Paul Mather wrote:
>> 
>> 
>> I also agree that this is a big disadvantage.  Whenever I make my
>> donation to the FreeBSD Foundation, and they ask in the donation form
>> for comments on what you want them to work/focus on in the future, I
>> always put a plug in for a native bhyve driver for docker-machine.
> 
> What would be run by the docker-machine in bhyve?


Basically, it would be the same thing you would run when you use docker-machine with the VirtualBox plugin: some sort of minimal shim Linux distribution (akin to boot2docker or whatever is used nowadays).


>> This would go some way to putting it on a par with Docker under macOS,
>> which uses HyperKit to interface with the built-in hypervisor under
>> macOS (which is based on bhyve).  MacOS is considered a "first class
>> citizen" under the Docker ecosystem, or at least has great support via
>> Docker Desktop.
> 
> What does MacOS run in its hypervisor by the docker-machine? Some linux
> flavor? It does not have a native docker server, does it?


Yes, AFAIK, macOS does not have a native Docker engine: it runs a small Linux shim.  As the Docker Desktop for Mac page (https://hub.docker.com/editions/community/docker-ce-desktop-mac) puts it, it features, "Fast and reliable performance with native macOS virtualization running a custom minimal Linux distro."

Bhyve = native FreeBSD virtualisation.


>> Last I looked, FreeBSD only supported VirtualBox with
>> docker-machine.  It would be great to have native bhyve support.
> 
> I agree.


It would only be a small step forward, but an improvement.  Right now, if you want to run Docker hosts on FreeBSD you typically have to use docker-machine with VirtualBox.  Having a bhyve docker-machine plugin would let you run Docker hosts via bhyve, which is now a native FreeBSD technology.  You wouldn't have to install the VirtualBox port, with the various headaches that brings involving keeping that port's kernel modules in sync with the installed kernel.

Docker is very well integrated with macOS via HyperKit/xhyve.  A similar approach should be possible under FreeBSD---probably not all the GUI integration, but at least for the Docker hosts.  As I keep saying, this strikes me as a support limitation, not a technical limitation when it comes to FreeBSD. :-)


> But I thought, perhaps with the Linux binary compatibility, we could
> avoid running a Linux in bhyve?


The original sysutils/docker-freebsd achieved just that.  It relied on FreeBSD's Linux compatibility to run Linux Docker images directly.  I believe problems with completeness of the Linux emulation, but, more so, the lack of maintainers/support for the port meant it fell behind and ultimately was deleted.


> Or can we convince Docker to start supporting jails (just a dream)?


It's not so strange.  There was some movement towards implementing the open container specification for FreeBSD a while ago, e.g., Jetpack (https://github.com/3ofcoins/jetpack) and runc (https://github.com/clovertrail/runc/tree/1501-SupportOnFreeBSD).  Jetpack (more inspired by rkt I believe) even uses jails as its isolation mechanism.

Unfortunately, these projects appear to have become inactive, but I guess they point to what is possible given the will and resources.

Native Docker containers under FreeBSD is not such a strange notion.  It's my impression that native Docker containers under Windows is quite a thing now. :-)

Cheers,

Paul.