Thanks Xenia.I also managed to solve the issue. Following is how I solved it. I ran netstat on all the computers of my cluster, and I ran the gripah job in parallel.I then learnt that this process runs on 127.0.0.1 while other machine tries to connect on 172.21.xx.xxx. That's why It gives the error java.net.ConnectException Then opened the /etc/hosts file, I found that the hostname of the machine was also mapped to 127.0.0.1.I removed that entry and it worked. It took me quite a while to resolve this issue.
Anyway finally it worked. PuneetIIT Delhi, India On Tuesday, November 4, 2014 4:09 AM, Xenia Demetriou <xenia...@gmail.com> wrote: Hi Puneet, I am not an expert but I had the same error and I solved it by changing the hostnames of the cluster-Pcs in lowercase e.g Make iHadoop3 -> ihadoop3 -- Xenia 2014-11-02 14:08 GMT+02:00 Puneet Agarwal <puagar...@yahoo.com>: I have setup a cluster of 4 computers for running my Pregel jobs. When running a job I often get the following error (given below).I followed another thread in giraph forums and learnt that this problem is because of the firewall stopping network traffic.I have stopped the firewall service on all the machines. These are machines have RHEL 5.5 and I stopped the service using the command - "service iptables stop" But I still get the same error. Can someone tell me what could be causing this service to be blocked on port 30001 on this computer? RegardsPuneet (IIT Delhi, India) Re: Problem running the PageRank example in a cluster | | | | | | | | | Re: Problem running the PageRank example in a clusterthis is the output of the command in all servers:Chain INPUT (policy ACCEPT)target prot opt source destinationACCEPT tcp -- anywhere anywhere stateNEW tcp dpts:30000:30010ACCEPT tcp -- anywhere anywhere ... | | | | View on mail-archives.apache.org | Preview by Yahoo | | | | | Error===========Using Netty without authentication. 2014-11-02 14:26:24,458 WARN org.apache.giraph.comm.netty.NettyClient: connectAllAddresses: Future failed to connect with iHadoop3/172.21.208.178:30001 with 0 failures because of java.net.ConnectException: Connection refused 2014-11-02 14:26:24,458 INFO org.apache.giraph.comm.netty.NettyClient: Using Netty without authentication. 2014-11-02 14:26:24,459 INFO org.apache.giraph.comm.netty.NettyClient: connectAllAddresses: Successfully added 0 connections, (0 total connected) 1 failed, 1 failures total. 2014-11-02 14:26:24,499 WARN org.apache.giraph.comm.netty.handler.ResponseClientHandler: exceptionCaught: Channel failed with remote address null java.net.ConnectException: Connection refused at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)2014-11-02 14:26:24,459 INFO org.apache.giraph.comm.netty.NettyClient: connectAllAddresses: Successfully added 0 connections, (0 total connected) 1 failed, 1 failures total. 2014-11-02 14:26:24,499 WARN org.apache.giraph.comm.netty.handler.ResponseClientHandler: exceptionCaught: Channel failed with remote address null java.net.ConnectException: Connection refusedjava.net.ConnectException: Connection refused