[Lxc-users] Installing Centos6 lxc guests under CentOS6 hosts

[Fajar A. Nugraha]

On Sat, Mar 10, 2012 at 6:57 PM, carlopmart <carlopmart at gmail.com> wrote:
> Hi all,
>
>   I am trying to install a centos 6.2 container under centos 6.2 host
> using libvirt and virt-manager. I have selected "OS Container" option,
> but when I try to launch this guest virt-manager returns me this error:
>
> PATH=/sbin:/usr/sbin:/bin:/usr/bin LIBVIRT_DEBUG=3
> LIBVIRT_LOG_OUTPUTS=3:stderr /usr/libexec/libvirt_lxc --name mysqlsrv
> --console 20 --handshake 23 --background --veth veth1 PATH=/bin:/sbin
> TERM=linux LIBVIRT_LXC_UUID=41bfb51b-294e-1ba9-16c9-fc2e3a345ff6
> LIBVIRT_LXC_NAME=mysqlsrv /sbin/init
> 16:39:23.115: 1: info : libvirt version: 0.9.4, package: 23.el6_2.6
> 16:39:23.115: 1: error : lxcContainerChild:896 : cannot find init path
> '/sbin/init' relative to container root: No such file or directory

Where is the container root? Do you have /sbin/init there?

>
>  I have followed these instructions: http://libvirt.org/drvlxc.html
> and
> http://berrange.com/posts/2011/09/27/getting-started-with-lxc-using-libvirt/
>
>  I have tried to do the same using rhel6.2 instead of centos 6.2 and
> results are the same ...
>
>  What am I doing wrong?? Do I need to copy all host files to this
> guest??

At minimum, the guest should have /sbin/init under its own root. On
the last link you gave, see "A private root filesystem with busybox"
for a very-simplified example.

If you want a full-blown installation, then yes, you need to have a
working OS installation in the guest. This can be created with yum, or
copying from existing system, or using templates.

> If yes, then, how can I apply security updates to lxc guests??

The way you do on normal system: yum update. ON THE GUEST.

FWIW, the upcoming Ubuntu 12.04 will have excellent lxc support for
both host and guest, with lxc command line tools (lxc-create,
lxc-start, lxc-console, etc). Other systems might require more effort
to get a fully working container. And to be honest, I'm not sure how
good Centos 6.2 would function as a host do to somewhat-old 2.6.32
kernel.

I have a short howto on how to create Centos5 guest:
http://wiki.1tux.org/wiki/Lxc/Installation/Guest/Centos/5 . Haven't
had time to create one for Centos6 guest yet, but at least the above
should give an idea of how to install a guest manually. You might also
want to look at templates/lxc-fedora from the lattest userspace tools
tarball (http://lxc.sourceforge.net/download/lxc/)

-- 
Fajar