Hello Ted, Can you point to a good implementation of that single file leadership election method you're describing ?
Thanks, Jérémie On Sat, Nov 26, 2011 at 8:37 AM, Ted Dunning <ted.dunn...@gmail.com> wrote: > I think that the code also needs: > > * comments. You need to put some java docs in that say what the different > classes and methods are intended to do. External documentation is nice, > but hardly sufficient. > > * global handling of disconnection and pausing of masters during a > disconnect. > > * a description of how you think you are handling error conditions > > * tests that demonstrate that you handle error conditions > > I would also take issue with Jordan's suggestion for retry logic. With > ephemeral sequential node, retries are very dangerous in certain corner > failure modes. This is the primary reason that I prefer the single file > leader election method. With a reasonable number of masters (the most > common case) this is completely sufficient since the herd effect isn't a > problem for such a small herd. > > On Fri, Nov 25, 2011 at 10:17 PM, Jordan Zimmerman > <jzimmer...@netflix.com>wrote: > >> A few comments: >> >> * NodeMonitor.createRootIfNotExists() should catch NodeExists. In the case >> of multiple clients, this is a possibility. >> >> * I'd add a start method and create the ZooKeeper instance there. This >> gives users a chance to set a listener so as to receive all messages. >> >> * All ZooKeeper operations should be in some kind of retry loop. The >> client can lose connection to a given server but successfully reconnect to >> another one in the cluster. >> >> * When creating the Znode, it can succeed on the server but fail to return >> the result to the client. On a Disconnect/Session exception, you should >> retry and then call getChildren and search for your node. >> >> -JZ >> >> On 11/25/11 2:45 AM, "Olivier Van Acker" <cyberroa...@gmail.com> wrote: >> >> >I've written a example app on how to do implement leadership election in >> >with zookeeper >> >Is there anyone on the list who'd like to review my app and if it needs >> >improvement or not? >> > >> >the app is on github: >> >https://github.com/cyberroadie/zookeeper-leader >> > >> >and explained how it works on my blog: >> > >> http://cyberroadie.wordpress.com/2011/11/24/implementing-leader-election-w >> >ith-zookeeper/ >> > >> >Olivier >> >> > -- Jérémie 'ahFeel' BORDIER
