On Thu, 2018-02-15 at 19:52 +0100, David Disseldorp wrote: > Hi Jeff, > > On Thu, 15 Feb 2018 13:09:45 -0500, Jeff Layton wrote: > > > IIUC, if the program (samba in this case) dies, and then is restarted > > (maybe host reboots?), it'll get a new instance_guid, right? Or am I > > misunderstanding what rados_get_instance_id will return here? > > Yes, that's right. On smbd restart it'll reconnect and get a new > instance ID. The hostname is carried in the metadata, which makes it a > little easier to identify what's going on from the Ceph side. > > AFAICT the service record (unfortunately) remains present after > rados_shutdown() until a timeout on the manager is tripped, so > it's quite possible to have to registrations for the same host for a > short amount of time. > > Cheers, David Got it, thanks. I guess the fact that it changes it not a problem here? I'm not that well versed in what ceph-mgr does, tbqh... One thing you may want to be careful about: I found some thread safety problems a few months ago in how CephContext objects are handled in the ceph code. While I patched them up as best I could, a lot of older shipping versions still have those bugs. Even with those fixes, I think there may still be lurking problems when we have multiple ceph/rados clients within the same process image. The upshot here is that if you have the rados client here and (e.g.) a vfs_ceph client for exporting cephfs, you can hit some races particularly on setup and teardown of those clients that can cause crashes. libcephfs has a ceph_create_with_context image and librados has something similar. You might consider having a truly global cct object, and then have the vfs_ceph create a client handle with the same object. -- Jeff Layton <jlayton@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
