2009/4/2 Daniel P. Berrange <berrange(a)redhat.com <mailto:berrange@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 parameters > like memory, CPU etc. This parameters are not properties of <filesystem>. > > 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 virDomainTemplatePtr; int virConnectListDomainTemplates(virConnectPtr conn, const char **names); 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.

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. Per-container OpenVZ config keeps the name of the original config (in ORIGIN_SAMPLE variable).

Is there need for "Template API" in case of other hypervisors? ------------------------------------------------------------------------ -- Libvir-list mailing list Libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list