> -----Original Message----- > From: Xen-devel <xen-devel-boun...@lists.xenproject.org> On Behalf Of Juergen > Gross > Sent: 18 July 2019 10:00 > To: Andrew Cooper <andrew.coop...@citrix.com>; Sarah Newman <s...@prgmr.com>; > Foerster, Leonard > <foers...@amazon.com>; xen-devel@lists.xenproject.org > Subject: Re: [Xen-devel] Design session report: Live-Updating Xen > > On 17.07.19 00:27, Andrew Cooper wrote: > > On 16/07/2019 05:20, Sarah Newman wrote: > >> On 7/15/19 8:48 PM, Juergen Gross wrote: > >>> On 15.07.19 21:31, Sarah Newman wrote: > >>>> On 7/15/19 11:57 AM, Foerster, Leonard wrote: > >>>> ... > >>>>> A key cornerstone for Live-update is guest transparent live migration > >>>> ... > >>>>> -> for live migration: domid is a problem in this case > >>>>> -> randomize and pray does not work on smaller fleets > >>>>> -> this is not a problem for live-update > >>>>> -> BUT: as a community we shoudl make this restriction go away > >>>> > >>>> Andrew Cooper pointed out to me that manually assigning domain IDs > >>>> is supported in much of the code already. If guest transparent live > >>>> migration gets merged, we'll look at passing in a domain ID to xl, > >>>> which would be good enough for us. I don't know about the other > >>>> toolstacks. > >>> > >>> The main problem is the case where on the target host the domid of the > >>> migrated domain is already in use by another domain. So you either need > >>> a domid allocator spanning all hosts or the change of domid during > >>> migration must be hidden from the guest for guest transparent migration. > >> > >> Yes. There are some cluster management systems which use xl rather > >> than xapi. > >> They could be extended to manage domain IDs if it's too difficult to > >> allow > >> the domain ID to change during migration. > > > > For a v1 feature, having a restriction of "you must manage domids across > > the cluster" is a fine. Guest-transparent migration is a very important > > feature, and one where we are lacking in relation to other hypervisors. > > > > Longer term, we as the Xen community need to figure out a way to remove > > the dependency on domids, at which point the cluster-wide management > > restriction can be dropped. This isn't going to be a trivial task, but > > it will be a worthwhile one. > > Another problem are Xenstore watches. With guest transparent LM they are > lost today as there is currently no way to migrate them to the target > Xenstore. > > Live-Update could work around this issue via Xenstore-stubdom.
Watches are one problem. There's also the problem of pending transactions. Paul > > > Juergen > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xenproject.org > https://lists.xenproject.org/mailman/listinfo/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
