[libvirt-users] read-only rootfs for lxc containers

[Daniel P. Berrange]

On Thu, Dec 08, 2011 at 07:34:13AM -0800, Chris Haumesser wrote:
> And speaking of running out of a shared read-only root, I get the
> following error when I attempt it:
> 
> error: Failed to start domain hw
> error: internal error guest failed to start: PATH=/bin:/sbin TERM=linux
> LIBVIRT_LXC_UUID=38320e75-1ba0-d85a-6138-532a3a66f13d
> LIBVIRT_LXC_NAME=hw /bin/bash
> 2011-12-08 15:31:41.945: 1: info : libvirt version: 0.9.7
> 2011-12-08 15:31:41.945: 1: error : lxcContainerPivotRoot:345 : Failed
> to create /mnt/vmroot/.oldroot: Read-only file system
> 2011-12-08 15:31:41.945: 2666: info : libvirt version: 0.9.7
> 2011-12-08 15:31:41.945: 2666: error : lxcControllerRun:1210 : error
> receiving signal from container: Input/output error

Hmm, so your actual filesystem on the host side is read only ?

I'd not considered that possibilty. When I've done read-only
roots for containers, the host side was always writable, and
then I used  '<readonly/>' in the <filesystem> tag to make
the container see it readoly.


I'll have to think about how to make it work when the host
FS itself is readonly. Probably have to define some location
that is guarenteed to exist, instead of trying to create a
'/.oldroot' location ourselves.

Daniel
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