Metadata is supposed to be user "tags" that are associated with a guest that are available via the api. We discussed displaying these tags inside the guest as well.
The main difference between user-data and metadata is that metadata is available to the api, whereas user-data is only available in the guest. Vish On Jul 3, 2012, at 10:05 AM, Scott Moser wrote: > Hi, > I'm looking at nova, and the compute API has 3 methods: > delete_instance_metadata > update_instance_metadata > get_instance_metadata > > I know that > * python nova client has > * the ability to specify --meta=KEY=VALUE on instance creation > * a top level subcommand 'meta' which allows set and delete of > metadata keys (but no support for querying current value). > * content specified on instance creation is injected into the > instance's root filesystem at '/meta.js'. Or, if config_drive > is given the config drive will have /meta.js > > What I'm missing is: > * There is an 'update' for this content, implying that it is at least > partially dynamic in intent, but the filesystem data passing mechanism > is clearly *not* dynamic. > * This data is not made available in the metadata server > (http://169.254.169.254) where it *could* be dynamic. > > So, I'm confused on the intent of this metadata. I can't decide if it is > really just supposed to be "tags" or more of a user-data replacement. > > In EC2, you can store arbitrary key/value pairs on an instance-id, > ami-id, or anything else, but those values are not readable without > credentials. Here, they're readable inside the instance from the > filesystem. > > Anyone able to comment on the original intent of 'metadata'? > It seems to me that if we expose this in the metadata server, then it will > be a very useful feature, but one that overlaps confusingly with > user-data. > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp