So shouldn't all servers in another DC just have one session? So even if I have 50 observers in another DC that should be 50 sessions established since the IP doesn't change correct? Am I missing something? In some ZK clients I see the following exception even though they are in the same DC.
WARN - Session 0x0 for server msgzkapp013.abc.com/10.138.43.219:5001, unexpected error, closing socket connection and attempting reconnect java.io.IOException: Connection reset by peer at sun.nio.ch.FileDispatcher.read0(Native Method) at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21) at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233) at sun.nio.ch.IOUtil.read(IOUtil.java:200) at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236) at org.apache.zookeeper.ClientCnxn$SendThread.doIO(ClientCnxn.java:817) at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1089) WARN - Session 0x0 for server msgzkapp012.abc.com/10.138.42.219:5001, unexpected error, closing socket connection and attempting reconnect java.io.IOException: Connection reset by peer at sun.nio.ch.FileDispatcher.write0(Native Method) at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29) at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:104) at sun.nio.ch.IOUtil.write(IOUtil.java:75) at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:334) at org.apache.zookeeper.ClientCnxn$SendThread.doIO(ClientCnxn.java:851) at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1089) What might be happening in this case? Cheers Avinash On Tue, Oct 5, 2010 at 9:47 AM, Patrick Hunt <ph...@apache.org> wrote: > "A" (/10.30.84.207 a zookeeper client) is attempting to establish more > then 10 sessions to the ZooKeeper server where you got the log. This can be > caused by a bug in user code (we've seen bugs where incorrectly implemented > ZK clients attempt to create an infinite number of sessions, which > essentially DOS the service, so we added the maxClientCnxn default limit of > 10). > > Often users see this problem when they are trying to simulate a real > environment - they run a simulated set of clients sessions (>10) from a > single host (ip) hitting the servers. However in your case I'm guessing that > it has something to do with this > > "The observers are running in a different data center from where the ZK > non-observers are running." > > Could you have a NAT or some other networking configuration that makes all > the observers seem to be coming from the same IP address? > > Patrick > > On Tue, Oct 5, 2010 at 9:33 AM, Avinash Lakshman < > avinash.laksh...@gmail.com> wrote: > >> Thanks Patrick. But what does this mean? I see the log on server A telling >> me "Too many connections from A - default is 10". Too many connection from >> A >> to whom? I do not see who the other end of the connection is. >> >> Cheers >> Avinash >> >> On Tue, Oct 5, 2010 at 9:27 AM, Patrick Hunt <ph...@apache.org> wrote: >> >> > See this configuration param in the docs "maxClientCnxns": >> > >> > >> http://hadoop.apache.org/zookeeper/docs/current/zookeeperAdmin.html#sc_advancedConfiguration >> > >> > < >> > >> http://hadoop.apache.org/zookeeper/docs/current/zookeeperAdmin.html#sc_advancedConfiguration >> > > >> > Patrick >> > >> > On Tue, Oct 5, 2010 at 8:10 AM, Avinash Lakshman < >> > avinash.laksh...@gmail.com >> > > wrote: >> > >> > > I find this happening in my observers node in the logs. The observers >> are >> > > running in a different data center from where the ZK non-observers are >> > > running. The only way to fix this seems to be restarting. How can I >> start >> > > addressing this? Here is the stack trace. >> > > >> > > Too many connections from /10.30.84.207 - max is 10 >> > > WARN - Session 0x0 for server mybox.mydomain.com/10.30.84.207:5001, >> > > unexpected error, closing socket connection and attempting reconnect >> > > java.io.IOException: Connection reset by peer >> > > at sun.nio.ch.FileDispatcher.read0(Native Method) >> > > at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21) >> > > at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233) >> > > at sun.nio.ch.IOUtil.read(IOUtil.java:200) >> > > at >> sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236) >> > > at >> > > org.apache.zookeeper.ClientCnxn$SendThread.doIO(ClientCnxn.java:817) >> > > at >> > > org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1089) >> > > >> > > Please advice. >> > > >> > > Cheers >> > > Avinash >> > > >> > >> > >