Worst case option would be to have jvm shutdownhooks http://stackoverflow.com/questions/40376/handle-signals-in-the-java-virtual-machine
You can delete the znodes on exit. More like deleteOnExit functionality of a File thanks, Kishore G On Thu, Feb 4, 2010 at 2:56 PM, Patrick Hunt <ph...@apache.org> wrote: > hah, you guys beat me to the punch. I think having some unique per client > token might also work (see my resp). Perhaps this is the ip of the host or > better (esp if multiple clients on a single host) would be some solr > specific id that uniquely identifies each node. > > Patrick > > > Benjamin Reed wrote: > >> i second ted's proposals! thanx ted. >> >> there is one other option. when you create the ZooKeeper object you can >> pass a session id and password. your bounced server can actually reattach to >> the session. (that is why we put that constructor in.) to use it you need to >> save the session id and password to a persistent store (a file) when you >> first attach, and then when you restart read the id and password from the >> file. >> >> ben >> >> Ted Dunning wrote: >> >>> On Thu, Feb 4, 2010 at 2:20 PM, Yonik Seeley <yo...@lucidimagination.com >>> >wrote: >>> >>> >>> >>>> There's no way to "hand over" responsibility for an ephemeral znode, >>>> right? >>>> >>>> >>>> >>> >>> Right. >>> >>> >>> >>> >>>> We have solr nodes create ephemeral znodes (name based on host and >>>> port). >>>> The ephemeral znode takes some time to remove of course, so what >>>> happens is that if I bounce a solr server (containing a zk client) the >>>> ephemeral node will still exist when the server comes back up. >>>> >>>> >>>> >>> >>> This problem comes up with any system that has hysteresis and needs a >>> single >>> point of control. >>> >>> >>> >>> >>>> What's the best way to handle this situation? Delete and re-create? >>>> >>>> >>>> >>> Watch it and re-create when it does disappear? >>> I think you need to handle the problem of multiple search nodes coming >>> up on >>> the same machine, possibly because the old one may have hung up. >>> >>> So... I would recommend >>> >>> a) if the ephemeral still exists, wait for a few more seconds to see if >>> it >>> disappears (20?) >>> >>> b) if it goes away, create a new one and continue as normal >>> >>> c) if it doesn't go away take additional action to determine if service >>> is >>> still running (i.e. panic and run in circles). >>> >>> >> >>
