Thanks Andries for this explanation.. Addition of DNS entries in host file worked for me..
Regards, *Anup Tiwari* On Thu, Dec 1, 2016 at 9:12 PM, Andries Engelbrecht < aengelbre...@maprtech.com> wrote: > When using ZK connection string with either JDBC or ODBC always make sure > that the hostnames can be resolved. > > See http://drill.apache.org/docs/odbc-configuration-reference/ < > http://drill.apache.org/docs/odbc-configuration-reference/> > > Also make sure that hostnames can be resolved for all Drillbit nodes. > > A short explanation of the mechanics. > > - When the drillbits start up they register with ZK > - ZK keeps the list of available drillbits that registered and HOSTNAMES > of the nodes (not IPs) - use zkCli.sh to check the registered nodes and > actual resolution with GET in ZK > - When the the client uses ODBC or JDBC to connect to ZK it gets the list > of available drillbits and chooses one drillbit to connect to by using the > HOSTNAME > - The client then tries to connect to the chosen drillbit using the ZK > info (which is the hostname) > > If the client is unable to resolve the hostname of the drillbit that was > chosen it will fail. > > Using ZK connection allows for HA in terms of new connections as well as > balances the connection management and foreman duties for multiple > connections by spreading it over the registered drillbits. Connecting > directly to a drillbit is good for testing purposes, but not ideal for > larger scale and production environments. > > > --Andries > > > > On Dec 1, 2016, at 5:01 AM, Anup Tiwari <anup.tiw...@games24x7.com> > wrote: > > > > Hi Team, > > > > I am trying to connect to my drill cluster from tableau using MapR Drill > > ODBC Driver. > > > > I followed steps given in > > https://drill.apache.org/docs/using-apache-drill-with-tableau-9-server/ > and > > subsequent links and successfully connected to individual "direct > drillbit" > > reading docs. But when i am trying to connect to "zookeeper quorum" > instead > > of "direct drillbit", i am getting below error on MapR interface : > > > > FAILED! > > [MapR][Drill] (1010) Error occurred while trying to connect: > [MapR][Drill] > > (20) The hostname of '10.x.x.x' cannot be resolved. Please check your DNS > > setup or connect directly to Drillbit. > > > > Please note that since i am giving directly IP(Drill Hosts which are on > > AWS) so i believe i don't have to maintain DNS entries in host file. > > > > Also corresponding zookeeper logs are as follows :- > > > > 2016-12-01 18:08:42,541 [myid:3] - INFO [NIOServerCxn.Factory: > > 0.0.0.0/0.0.0.0:2181:NIOServerCnxnFactory@192] - Accepted socket > connection > > from /192.*.*.*:53159 > > 2016-12-01 18:08:42,543 [myid:3] - WARN [NIOServerCxn.Factory: > > 0.0.0.0/0.0.0.0:2181:ZooKeeperServer@854] - Connection request from old > > client /192.*.*.*:53159; will be dropped if server is in r-o mode > > 2016-12-01 18:08:42,543 [myid:3] - INFO [NIOServerCxn.Factory: > > 0.0.0.0/0.0.0.0:2181:ZooKeeperServer@900] - Client attempting to > establish > > new session at /192.*.*.*:53159 > > 2016-12-01 18:08:42,546 [myid:3] - INFO > > [CommitProcessor:3:ZooKeeperServer@645] - Established session > > 0x358ba2951720006 with negotiated timeout 30000 for client > /192.*.*.*:53159 > > 2016-12-01 18:08:42,793 [myid:3] - WARN [NIOServerCxn.Factory: > > 0.0.0.0/0.0.0.0:2181:NIOServerCnxn@357] - caught end of stream exception > > EndOfStreamException: Unable to read additional data from client > sessionid > > 0x358ba2951720006, likely client has closed socket > > at > > org.apache.zookeeper.server.NIOServerCnxn.doIO(NIOServerCnxn.java:230) > > at > > org.apache.zookeeper.server.NIOServerCnxnFactory.run( > NIOServerCnxnFactory.java:203) > > at java.lang.Thread.run(Thread.java:745) > > 2016-12-01 18:08:42,794 [myid:3] - INFO [NIOServerCxn.Factory: > > 0.0.0.0/0.0.0.0:2181:NIOServerCnxn@1008] - Closed socket connection for > > client /192.*.*.*:53159 which had sessionid 0x358ba2951720006 > > 2016-12-01 18:08:42,795 [myid:3] - ERROR > > [CommitProcessor:3:NIOServerCnxn@178] - Unexpected Exception: > > java.nio.channels.CancelledKeyException > > at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:73) > > at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:77) > > at > > org.apache.zookeeper.server.NIOServerCnxn.sendBuffer( > NIOServerCnxn.java:151) > > at > > org.apache.zookeeper.server.NIOServerCnxn.sendResponse( > NIOServerCnxn.java:1082) > > at > > org.apache.zookeeper.server.FinalRequestProcessor.processRequest( > FinalRequestProcessor.java:404) > > at > > org.apache.zookeeper.server.quorum.CommitProcessor.run( > CommitProcessor.java:77) > > > > > > I have gone through this link but this doesn't helped me :- > > http://stackoverflow.com/questions/30940981/zookeeper- > error-cannot-open-channel-to-x-at-election-address > > > > Regards, > > *Anup Tiwari* > >
