On Mon, Sep 21, 2009 at 3:21 PM, Michael Hanselmann <[email protected]> wrote: > > 2009/9/21 Iustin Pop <[email protected]>: >> --- a/doc/design-2.1.rst >> +++ b/doc/design-2.1.rst >> +Introducting persistent UUIDs > > s/Introducting/Introducing/ > >> +Upgrading from Ganeti 2.0 will add automatically uuids to all entities >> +missing them. > > For consistency and because it's an acronym, write “UUID” always in uppercase. > >> +In the next release (e.g. 2.2), the tracking of objects will change > > s/next release/next minor release/ > >> +from the name to the UUID internally, and externally Ganeti will >> +accept both forms of identification; e.g. an RAPI call would be made >> +either against ``/2/instances/foo.bar`` or against >> +``/2/instances/bb3b2e42…``. > > Not that I expect this to happen, but what if someone used UUIDs to > name existing machines? Should UUID names have a prefix which will no > longer be allowed for instance names?
Is this a problem? In the end UUIDs should be unique, so the UUID a machine has has to be different from the UUID another one has a hostname! :) Maybe just a check that the new UUID doesn't match any existing hostname, and otherwise use a new one? Also, just a curiosity: how do we plan to support name-access? via a search through all instances/nodes? If we maintain a cache we need to make sure we update the cache as well as the object on name change, which is still better than updating everything, but anyway keeps the same information in many places. And what's the reason not to do it right away and stage the changes? Too complicated for the remaining 2.1 development time or? Thanks! Guido > >> +Internal tracking refers to the way the configuration is stored; a >> +DRBD disk of an instance refers to the node name (so that IPs can be >> +changed easily), but this is still a problem for name changes; thus >> +these will be changed to point to the node name to ease renames. > > I guess you mean “node UUID” in the last sentence. > >> +The advantages of this change (after the second round of changes), if > > s/if/is/? > >> +that node rename becomes trivial, whereas today node rename would >> +require a complete lock of all instances. > > Regards, > Michael > -- Guido Trotter Google - Sysops Team Google Ireland Ltd. : Registered in Ireland with company number 368047. Gordon House, Barrow Street, Dublin 4, Ireland.
