Hi Zookeepers, I am also experiencing the similar problem since yestderday. I have pretty much similar setup and ephemeral znodes in place for keep-alive kind of function. I too see in spite of ZK session going down, ephemeral znodes still LIVES.
I am using ZK 3.5.0. Any solution/fix for this type of an issue?? -- Sincerely, *Yogesh Patil* On Thu, Nov 13, 2014 at 2:10 PM, Kuba Lekstan <[email protected]> wrote: > Sorry, forgot to mention. Version: 3.4.6. > > Thanks. > > 2014-11-13 18:11 GMT+01:00 German Blanco <[email protected]>: > > > Hello, > > > > which version of Zookeeper are you using? > > > > On Thu, Nov 13, 2014 at 5:25 PM, Kuba Lekstan <[email protected]> wrote: > > > > > Hello, > > > > > > A bit of details: > > > We have 5 node cluster, which we use for configuration distrubution and > > > monitoring active instances of our applications. Each application > creates > > > its ephemeral node, so we know which apps are alive, how many of them > > there > > > is and what they are doing. > > > > > > The problem had happen at 4th November, first time it was around 4AM, > > > second time around 12PM. > > > First time it was middle of the night when I got woken up, the support > > guys > > > told me that something is wrong with config distribution. > > > > > > First I've checked apps for errors but didn't find anything > interesting, > > > then I looked at what's in zookeeper (using node-zk-browser). > > > I've noticed that there are 3 ephemeral nodes which were created at 1st > > nov > > > (while the oldest application was started on 3rd nov), I could read its > > > data but was not able to delete them - was getting NONODE exception. > > > > > > I thought wtf - why I cannot delete these nodes, something very bad had > > to > > > happen with ZK. > > > > > > So I sshed on the leader and using CLI I tried to read these nodes but > I > > > was not able to - the leader was telling me that such nodes doesn't > > exist. > > > After this I started to ssh to the rest of the nodes in cluster and > > trying > > > to read these nodes. Finally I found the server which did let me read > the > > > data of these nodes. > > > Because of the inconsistency I've decided to restart it. Restart did > > help, > > > everything went back to normal state. The ephemeral nodes disappeared. > > > > > > Similar situation had happen at 12PM but this time I had a lot more > time > > to > > > look what is wrong. Second time the problem was about 3 ephemeral nodes > > > which were created at 1st now (again?). This time I dig a bit deeper > and > > > look into logs and 4 letter commands - but could not find anything > > > interesting except the all these 3 nodes were created under different > > > sessionids but zk had no hosts connected under this sessionids. > > > Solution was similar to the one from 4AM but this time I've delete all > > > files in ZK data directory. > > > > > > Oddly enough the problem happened twice on the same ZK node, the final > > > solution was to clear ZK data directory. After clearing the directory > the > > > problem didn't happen again. > > > > > > I tried to look for solution/similar problems, I found the posts where > > > people were complaining about ephemeral nodes not being removed after > > > client session gets closed. But I was not able to find posts about ZK > not > > > being consistent. > > > > > > What do you think about this? Can we do something to fix this? > > > > > > Sorry for my english, I was doing my best. :) > > > > > > Thanks, Kuba. > > > > > >
