[CentOS-virt] CentOS-6.0 and LXC

Mon Jul 18 22:22:05 UTC 2011
Matt Paine <mattzerah at gmail.com>

As far as I am aware, KVM uses the cpu hardware to run completely different
operating systems independently of the host.

LXC is similar to Linux-VServer, or virtuozzo, where you are always running
a base kernel, and can run multiple init's at the same time. Each init (and
any processes spawed from that init) are completely isolated, which gives
the appearance of a different operating system being run. Note that each
container uses the same host kernel, so you cant run software that requires
older or newer kernels, or kernels which require specific modules that are
not in the host kernel. But you get the benefit that you dont need to switch
out entire OS images and/or virtualize hardware, processes are simply
scheduled as they would be normally. The only overhead is the extra
memory/cpu that the extra processes take up.

I like using linux-vserver as I can access my guests filesystem from my host
instance (as its usually just a subdirectory of the main filesystem). I also
like it as I can control the networking interfaces from the host with ease,
and my firewall is controlled from the host, so I know what traffic is going
in/out etc and what ports are open for all ip's on the box, through my
firewall rules in the central location. I'm not sure how LXC works this way,
as I think they virtualize the networking as well, which is why I'm keen to
try it out :)

Take what I say with a grain of salt too :)


On 19 July 2011 00:26, Always Learning <centos at u6.u22.net> wrote:

> On Mon, 2011-07-18 at 12:32 +0100, Karanbir Singh wrote:
> > afaik, LXC was on target for 6.2
> Can someone please summarise the main differences between KVM (Kernel
> Virtual Machine) and LXC (Linux Containers) which are similar to BSD
> jails ?
> Can one put KVMs into any quantity of LXCs ?
> Do LXCs run only with the main operating system, whereas KVM can run
> with a guest operating system ?
> Puuzzled.
> --
> With best regards,
> Paul.
> England,
> EU.
> _______________________________________________
> CentOS-virt mailing list
> CentOS-virt at centos.org
> http://lists.centos.org/mailman/listinfo/centos-virt
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