That’s correct Benjamin. As Curator wraps the library-provided ZooKeeper class there’s nothing Curator can do about this. I’ll try to write a Tech Note about this when I can. If you don’t mind, Benjamin, maybe you could write it?
https://cwiki.apache.org/confluence/display/CURATOR/Tech+Notes -Jordan > On Nov 2, 2016, at 11:08 AM, Benjamin Jaton <[email protected]> wrote: > > > In your example (conenctionTimeout = 10, sessionTimeout = 60, 3 nodes), if > the first node that gets picked up is down it will timeout after 20 sec. So > Curator would fail to connect yet the ensemble is available. > > How can this timeout after 20 secs, if the connection timeout is 10 seconds? > Also, > > Curator's connectionTimeout is to be understood as connection to the whole > ensemble, not individual node. > > How long do you think the ZooKeeper API will wait for a connection before > trying the next node? > The answer is sessionTimeout / #nodes = 60 / 3 = 20 seconds. > > 0 sec - try 1st node > 20 sec - try 2nd node > 40 sec - try 3rd node > > Now if Curator has a cap at 10 seconds, it won't wait for the ZK API to reach > the other 2 nodes. > > Hope that's clearer. > > Benjamin > > > So Curator would fail to connect yet the ensemble is available > > Can you explain the above statement then? As for my understanding, curator > will try all Zookeeper nodes until it connects to an up and running zookeeper > server or until the connection timeout. > > -Imesha > > On 2 November 2016 at 10:45, Cameron McKenzie <[email protected] > <mailto:[email protected]>> wrote: > Session timeout is a Zookeeper concept. It's just the amount of time (in MS) > that a client session can be idle for before the Zookeeper server times it > out. A heart beat keeps the session alive, so the session will only time out > due to network issues. > > The connection timeout is a Curator concept. Jordan described its use in this > thread. Basically, it just defines how long Curator will wait for a > connection to be established to Zookeeper before giving up and trying again. > > On Wed, Nov 2, 2016 at 4:00 PM, Imesha Sudasingha <[email protected] > <mailto:[email protected]>> wrote: > Hello all, > > I was going through this thread and found out I too need a clear explanation > on "what is connectionTimeout and sessionTimeout". Even though you have > discussed a lot about it(which I have read), still I'm not getting a clear > picture. Can someone elaborate on the it? And give a clear view of those 2 > parameters and what they are for? > > Thanks! > > Regards, > Imesha Sudasingha > > > On Nov 2, 2016 4:26 AM, "Jordan Zimmerman" <[email protected] > <mailto:[email protected]>> wrote: > >> so if we use a connectionTimeout smaller than sessionTimeout, we may fail >> before having tried all the nodes. > > That’s correct and up to you. That’s why these are configurable options. Use > values that make sense for your applications. > > -Jordan > > > > > > > > -- > Imesha Sudasingha > Undergraduate of Department of Computer Science and Engineering, > University of Moratuwa. > +94717086160 <tel:%2B94717086160> > View in Linkedin <https://lk.linkedin.com/in/imeshasudasingha>
