configuration files

[Urs Golla]

Hi

I am a bit confused about the configuration files for XEN user domains
in Fedora. Regarding to the Users’ Manual
for Xen v3.3 from xensource the configuration files should still be in
/etc/xen/ like they are on RHEL5. However, on F8 they are somewhere in
/var/lib/xen and have a new format (not XML?). Could someone please
provide a link to a changelog, release notes or any other "official"
documentation which describes this change? I could not really find an
answer on http://fedoraproject.org/wiki/Docs/Fedora8VirtQuickStart,
and I see that many users ask this questions in other boards or
mailing lists.

Regards
Urs

[Ján ONDREJ (SAL)]

Hi,

On Fri, Mar 13, 2009 at 10:27:16AM +0100, Urs Golla wrote:
> I am a bit confused about the configuration files for XEN user domains
> in Fedora. Regarding to the Users’ Manual
> for Xen v3.3 from xensource the configuration files should still be in
> /etc/xen/ like they are on RHEL5. However, on F8 they are somewhere in
> /var/lib/xen and have a new format (not XML?). Could someone please
> provide a link to a changelog, release notes or any other "official"
> documentation which describes this change? I could not really find an
> answer on http://fedoraproject.org/wiki/Docs/Fedora8VirtQuickStart,
> and I see that many users ask this questions in other boards or
> mailing lists.

You can use both of them. Original xen commands (xm) uses mostly text
configurations in /etc/xen, Fedora commands (virsh and command which use
this) are using XML configs from /var/lib.

SAL

[Urs Golla]

Hi,

ok, but why does the file in /var/lib/xend/dom-uuid/config.sxp use
such a strange syntax? I mean '()' instead of '<>' and an empty
element should look like <name attribute="value"/> not (name value).
if I dump the xml with virsh, it looks much more like a standard xml
to me.

Regards
Urs

On Fri, Mar 13, 2009 at 12:30 PM, Jan ONDREJ (SAL)  wrote:
> Hi,
>
> On Fri, Mar 13, 2009 at 10:27:16AM +0100, Urs Golla wrote:
> > I am a bit confused about the configuration files for XEN user domains
> > in Fedora. Regarding to the Users’ Manual
> > for Xen v3.3 from xensource the configuration files should still be in
> > /etc/xen/ like they are on RHEL5. However, on F8 they are somewhere in
> > /var/lib/xen and have a new format (not XML?). Could someone please
> > provide a link to a changelog, release notes or any other "official"
> > documentation which describes this change? I could not really find an
> > answer on http://fedoraproject.org/wiki/Docs/Fedora8VirtQuickStart,
> > and I see that many users ask this questions in other boards or
> > mailing lists.
>
> You can use both of them. Original xen commands (xm) uses mostly text
> configurations in /etc/xen, Fedora commands (virsh and command which use
> this) are using XML configs from /var/lib.
>                    SAL

[Markus Armbruster]

Urs Golla  writes:
> Hi,
>
> ok, but why does the file in /var/lib/xend/dom-uuid/config.sxp use
> such a strange syntax? I mean '()' instead of '<>' and an empty
> element should look like <name attribute="value"/> not (name value).

Because it's not XML.
> if I dump the xml with virsh, it looks much more like a standard xml
> to me.

Because it's XML.

The .sxp files use Xen's native syntax, which is from the sexp
family[*].  libvirt uses XML.

[*] http://en.wikipedia.org/wiki/S-expression

[Urs Golla]

Hi Markus

Thanks for your reply!
> Because it's not XML.

That really explains a lot ;-)

I always assumed the "legacy" format from /etc/xen/mydomainconfig
(like in RHEL 5) is the native XEN syntax (I see this is not the
case.).  So, the xml format from libvirt is like a replacement for the
configuration in /etc/xen/mydomainconfig? But if I use virt-install
(e.g. in Fedora 8) to install a new machine, it does not create a file
/etc/xen/ and also no xml. All It does is creating the s-expression
file in /var/lib/.

Is there a documentation about the relation between all this different
XEN / libvirt configuration files? The architecture part of the
documentation on libvirt.org does not answer this question.

cheers

On Mon, Mar 16, 2009 at 8:48 AM, Markus Armbruster  wrote:
> Urs Golla  writes:
> > Hi,
> >
> > ok, but why does the file in /var/lib/xend/dom-uuid/config.sxp use
> > such a strange syntax? I mean '()' instead of '<>' and an empty
> > element should look like <name attribute="value"/> not (name value).
>
> Because it's not XML.
> > if I dump the xml with virsh, it looks much more like a standard xml
> > to me.
>
> Because it's XML.
>
> The .sxp files use Xen's native syntax, which is from the sexp
> family[*].  libvirt uses XML.
>
> [*] http://en.wikipedia.org/wiki/S-expression

[Markus Armbruster]

Urs Golla  writes:
> Hi Markus
>
> Thanks for your reply!
> > Because it's not XML.
>
> That really explains a lot ;-)

;)
> I always assumed the "legacy" format from /etc/xen/mydomainconfig
> (like in RHEL 5) is the native XEN syntax (I see this is not the
> case.).  So, the xml format from libvirt is like a replacement for the
> configuration in /etc/xen/mydomainconfig? But if I use virt-install
> (e.g. in Fedora 8) to install a new machine, it does not create a file
> /etc/xen/ and also no xml. All It does is creating the s-expression
> file in /var/lib/.
>
> Is there a documentation about the relation between all this different
> XEN / libvirt configuration files? The architecture part of the
> documentation on libvirt.org does not answer this question.
>
> cheers

Xen uses *two* native configuration file formats: S-expressions and a
Python-like syntax.  The .sxp files you found below /var/lib/xend/ use
the former syntax, the guest configuration in /etc/xen the latter.

I'd recommend to stick to libvirt as much as possible.  Check "man
virsh", in particular the domain commands "dumpxml" and "define".

[Daniel P. Berrange]

On Mon, Mar 16, 2009 at 11:42:41AM +0100, Markus Armbruster wrote:
> Urs Golla  writes:
> > Hi Markus
> >
> > Thanks for your reply!
> > > Because it's not XML.
> >
> > That really explains a lot ;-)
>
> ;)
> > I always assumed the "legacy" format from /etc/xen/mydomainconfig
> > (like in RHEL 5) is the native XEN syntax (I see this is not the
> > case.).  So, the xml format from libvirt is like a replacement for the
> > configuration in /etc/xen/mydomainconfig? But if I use virt-install
> > (e.g. in Fedora 8) to install a new machine, it does not create a file
> > /etc/xen/ and also no xml. All It does is creating the s-expression
> > file in /var/lib/.
> >
> > Is there a documentation about the relation between all this different
> > XEN / libvirt configuration files? The architecture part of the
> > documentation on libvirt.org does not answer this question.
> >
> > cheers
>
> Xen uses *two* native configuration file formats: S-expressions and a
> Python-like syntax.  The .sxp files you found below /var/lib/xend/ use
> the former syntax, the guest configuration in /etc/xen the latter.

To be more specific

'xend' use /var/lib/xend for storing master config files in SXPR format.
 'xm' abuses python as a config file format in /etc/xen. XenD itself has
 no knowledge of these files, so it can't manage them. They should not
 be used in Xen >= 3.0.4 If you have existing files in /etc/xen, then you
 can load them into XenD by doing 'xm new configname', at which point
 both Xend and libvirt will be able to manage them. For Xen < 3.0.4
 libvirt has some limited support for reading /etc/xen files directly

Daniel

[Dustin Henning]

Response below...

-----Original Message-----
From: [e-mail] [mailto:[e-mail]]
On Behalf Of Daniel P. Berrange
Sent: Monday, March 16, 2009 07:18
To: Markus Armbruster
Cc: [e-mail]
Subject: Re: [Fedora-xen] configuration files

On Mon, Mar 16, 2009 at 11:42:41AM +0100, Markus Armbruster wrote:
> Urs Golla  writes:
> > Hi Markus
> >
> > Thanks for your reply!
> > > Because it's not XML.
> >
> > That really explains a lot ;-)
>
> ;)
> > I always assumed the "legacy" format from /etc/xen/mydomainconfig
> > (like in RHEL 5) is the native XEN syntax (I see this is not the
> > case.).  So, the xml format from libvirt is like a replacement for the
> > configuration in /etc/xen/mydomainconfig? But if I use virt-install
> > (e.g. in Fedora 8) to install a new machine, it does not create a file
> > /etc/xen/ and also no xml. All It does is creating the s-expression
> > file in /var/lib/.
> >
> > Is there a documentation about the relation between all this different
> > XEN / libvirt configuration files? The architecture part of the
> > documentation on libvirt.org does not answer this question.
> >
> > cheers
>
> Xen uses *two* native configuration file formats: S-expressions and a
> Python-like syntax.  The .sxp files you found below /var/lib/xend/ use
> the former syntax, the guest configuration in /etc/xen the latter.

To be more specific

'xend' use /var/lib/xend for storing master config files in SXPR format.
 'xm' abuses python as a config file format in /etc/xen. XenD itself has
 no knowledge of these files, so it can't manage them. They should not
 be used in Xen >= 3.0.4 If you have existing files in /etc/xen, then you
 can load them into XenD by doing 'xm new configname', at which point
 both Xend and libvirt will be able to manage them. For Xen < 3.0.4
 libvirt has some limited support for reading /etc/xen files directly

Daniel