On Wed, May 09, 2018 at 05:40 PM +0200, "Daniel P. Berrangé" <berrange@redhat.com> wrote:
On Wed, May 09, 2018 at 04:56:12PM +0200, Marc Hartmayer wrote:
Introduce new libvirt API virDomainCreateWithParams that allows to temporarily boot from another boot device, to use another kernel, initrd, and cmdline than defined in the persistent domain definition. All typed parameters are optional.
The design of the API was chosen to ease future extensions.
I don't really see the point in doing this. We already have the ability to temporary boot with a different configuration than is stored in the persistent XML. Just call virDomainCreateXML() passing in the alternative XML doc. This allows changing *any* aspect of the guest configuration, so we're not restricted to just bot device, kernel initrd and cmdline, and thus won't need to write more code anytime someone asks to be able to override something else too.
I know there is the API virDomainCreateXML for creating a transient domain and that it’s possible to temporarily replace parts of the persistent XML with it. But my idea is _not_ to add a functionality to override parts of the persistent XML. My idea is to provide support allowing an easy one-time switch of the boot device in a persistently defined domain. For s390 it’s essential to have an easy way to change the boot configuration since it “knows” only one boot device at a time and it has no support for interactively changing the boot device during the boot/IPL process. I started out with a fixed API (as it was done for example with virDomanCreateWithFiles) but than I liked the approach of providing an more extensible and flexible API better. This is also the reason why I used typed parameters for passing the arguments. This type of API is also not restricted to boot order changes since it could be freely expanded (e.g. passing file descriptors). I can certainly revert back to the static API.
Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
-- Beste Grüße / Kind regards Marc Hartmayer IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294