[libvirt] [PATCH] Openvz: how to use a nondefault config
evg at openvz.org
Mon Apr 6 08:59:01 UTC 2009
> 2009/4/2 Daniel P. Berrange <berrange at redhat.com
> <mailto:berrange at redhat.com>>
> On Thu, Apr 02, 2009 at 06:36:15PM +0400, Evgeniy Sokolov wrote:
> > Config /etc/vz/conf/ve-XXX.conf-sample define there are many
> > like memory, CPU etc. This parameters are not properties of
> > Daniel, usage of pre-defined configs in really usefull. Can we create
> > additional tag inside <domain></domain>?
> The trouble with this is that given the XML config of a guest, you can
> no longer determine what its configuration is, because a large amount
> of configuration is hidden in this opaque 'template'.
> And in kvm/qemu case there is a lot of hidden information too :)
> In OpenVZ case we don't loose any info (see below).
> If we're to support templates, I think we need to make them first class
> objects, so you can query what templates exist, and see their associated
> config settings.
> eg, expose a simple API
> int virConnectListDomainTemplates(virConnectPtr conn, const char
> virDomainTemplatePtr virDomainTemplateLookupbyName(virConnectPtr
> con, const char *name)
> char *virDomainTemplateGetXMLDesc(virDomainTemplatePtr tmpl);
> virDomainTemplatePtr virDomainTemplateDefineXML(virConnectPtr
> conn, const char *xml)
> int virDomainTemplateUndefine(virDomainTemplatePtr tmpl);
> int virDomainTemplateFree(virDomainTemplatePtr tmpl);
> Then, we could either include a <template>$NAME</template> parameter in
> the XML for a guest. Or have an alternate API for creating guests
> virDomainCreateXMLWithTemplate(virConnectPtr conn,
> const char *xmlDesc,
> const char *template)
> It depends whether we'd want to track the template <-> guest association
> forever, or just use it once to fill-in the guest XML and then forget
> about the template after that.
Template <-> guest association don't need. Information is used only once.
So, we will extend libvirt API by
and will include <template>$NAME</template> to <domain></domain>.
Daniel, is it correct?
> It doesn't matter in OpenVZ case: template (or, "config", in openvz
> terminology) is used only
> once, when container is creating. But then per-container "copy" is created,
> and it is already used by libvirt to keep information about container.
> OpenVZ config keeps the name of the original config (in ORIGIN_SAMPLE
ORIGIN_SAMPLE is not used by OpenVZ, and don't need. It is saved to
config for using external tools.
> Is there need for "Template API" in case of other hypervisors?
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