Technological advantages over Linux
paul at gromit.dlib.vt.edu
Fri Jul 24 23:30:36 UTC 2020
On Jul 24, 2020, at 1:56 PM, Steve O'Hara-Smith <steve at sohara.org> wrote:
> On Fri, 24 Jul 2020 12:00:16 -0400
> Paul Mather <paul at gromit.dlib.vt.edu> wrote:
>> Whenever Docker comes up, it seems to me that in the FreeBSD world the
>> cry that goes up is "they're just like jails." In my experience, though,
>> FreeBSD jails are more heavyweight than Docker containers. Jails in
>> FreeBSD are more analogous to using LXD in Linux---lightweight OS
> I think you mean LXC in Linux - Docker the engine is a built on top
> of LXC and filesystem layering. These days LXC is fronted by containerd in
> Docker which I believe allows for using other container technologies.
No, I meant LXD (https://linuxcontainers.org/lxd/), but I admit my use was confusing (as LXD != Docker). I was using LXD as an example in the Linux world of what iocage or ezjail or Bastile or pot or cbsd would be in the FreeBSD world---as a framework for managing lightweight OS servers. In other words, to me, LXD is closer in spirit (more so than Docker) to the way jails are used and managed by tools like iocage et al. in FreeBSD.
I agree that LXC is the basis of containers in Linux. LXD itself is just a management tool over LXC.
>> (What you say sounds like LXD OS containers to me.) What people want
> LXC == jails. Docker is a layer built on top of LXC and layered
> VFS mounts. It is perfectly possible to build something like Docker on top
> of jails, it is probably even possible to make Docker use jails. Of course
> the library of LXC based images would be useless but the stack on up to
> swarm and Kubernetes would all work.
It would be nice to make Docker use jails. I agree, the existing LXC-based images would be unusable (though not all LXC images are built and available for all architectures supported by LXC---most are for x86), but like Docker Windows Containers, an ecosystem for FreeBSD-compatible Docker containers could emerge. (And, with a bhyve plugin for docker-machine, all the LXC images would be useful.) The limitation is likely not technological but one of community and support.
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