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. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
