John, each instance of manila-share service will perform "ensure_share" operation for each "share instance" that is located at "hostname@driver_config_group_name". So, only one driver is expected to run "ensure_share" for some "share instance", because each instance of a driver will have its own unique value of "hostname@driver_config_group_name".
Valeriy On Fri, Mar 4, 2016 at 3:15 PM, John Spray <[email protected]> wrote: > On Fri, Mar 4, 2016 at 12:11 PM, Shinobu Kinjo <[email protected]> > wrote: > > What are you facing? > > In this particular instance, I'm dealing with a case where we may add > some metadata in ceph that will get updated by the driver, and I need > to know how I'm going to be called. I need to know whether e.g. I can > expect that ensure_share will only be called once at a time per share, > or whether it might be called multiple times in parallel, resulting in > a need for me to do more synchronisation a lower level. > > This is more complicated than locking, because where we update more > than one thing at a time we also have to deal with recovery (e.g. > manila crashed halfway through updating something in ceph and now I'm > recovering it), especially whether the places we do recovery will be > called concurrently or not. > > My very favourite answer here would be a pointer to some > documentation, but I'm guessing much this stuff is still at a "word of > mouth" stage. > > John > > > On Fri, Mar 4, 2016 at 9:06 PM, John Spray <[email protected]> wrote: > >> Hi, > >> > >> What expectations should driver authors have about multiple instances > >> of the driver being instantiated within different instances of > >> manila-share? > >> > >> For example, should I assume that when one instance of a driver is > >> having ensure_share called during startup, another instance of the > >> driver might be going through the same process on the same share at > >> the same time? Are there any rules at all? > >> > >> Thanks, > >> John > >> > >> > __________________________________________________________________________ > >> OpenStack Development Mailing List (not for usage questions) > >> Unsubscribe: > [email protected]?subject:unsubscribe > >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > > > > -- > > Email: > > [email protected] > > GitHub: > > shinobu-x > > Blog: > > Life with Distributed Computational System based on OpenSource > > > > > __________________________________________________________________________ > > OpenStack Development Mailing List (not for usage questions) > > Unsubscribe: > [email protected]?subject:unsubscribe > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: [email protected]?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > -- Kind Regards Valeriy Ponomaryov www.mirantis.com [email protected]
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