On 27 January 2014 14:52, Justin Santa Barbara <[email protected]> wrote: > Day, Phil wrote: > >> >> >> We already have a mechanism now where an instance can push metadata as >> >> a way of Windows instances sharing their passwords - so maybe this >> >> could >> >> build on that somehow - for example each instance pushes the data its >> >> willing to share with other instances owned by the same tenant ? >> > >> > I do like that and think it would be very cool, but it is much more >> > complex to >> > implement I think. >> >> I don't think its that complicated - just needs one extra attribute stored >> per instance (for example into instance_system_metadata) which allows the >> instance to be included in the list > > > Ah - OK, I think I better understand what you're proposing, and I do like > it. The hardest bit of having the metadata store be full read/write would > be defining what is and is not allowed (rate-limits, size-limits, etc). I > worry that you end up with a new key-value store, and with per-instance > credentials. That would be a separate discussion: this blueprint is trying > to provide a focused replacement for multicast discovery for the cloud. > > But: thank you for reminding me about the Windows password though... It may > provide a reasonable model: > > We would have a new endpoint, say 'discovery'. An instance can POST a > single string value to the endpoint. A GET on the endpoint will return any > values posted by all instances in the same project. > > One key only; name not publicly exposed ('discovery_datum'?); 255 bytes of > value only. > > I expect most instances will just post their IPs, but I expect other uses > will be found. > > If I provided a patch that worked in this way, would you/others be on-board?
I like that idea. Seems like a good compromise. I have added my review comments to the blueprint. We have this related blueprints going on, setting metadata on a particular server, rather than a group: https://blueprints.launchpad.net/nova/+spec/metadata-service-callbacks It is limiting things using the existing Quota on metadata updates. It would be good to agree a similar format between the two. John _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
