Important is, that the canonical name must be the FQDN of the server, see the example.
1.1.1.1 one.one.org one namenode 1.1.1.2 two.one.og two datanode If DNS is used the system’s hostname must match the FQDN in forward as well as reverse name resolution. BR, Alex > On 22 Feb 2015, at 21:51, tesm...@gmail.com wrote: > > I am getting java.net.UnknownHost exception continuously on one node Hadoop > MApReduce execution. > > That node is accessible via SSH. This node is shown in "yarn node -list" and > "hadfs dfsadmin -report" queries. > > Below is the log from execution.... > > 15/02/22 20:17:42 INFO mapreduce.Job: Task Id : > attempt_1424622614381_0008_m_000043_0, Status : FAILED > Container launch failed for container_1424622614381_0008_01_000016 : > java.lang.IllegalArgumentException: java.net.UnknownHostException: > 101-master10 > at > org.apache.hadoop.security.SecurityUtil.buildTokenService(SecurityUtil.java:373) > at > org.apache.hadoop.security.SecurityUtil.setTokenService(SecurityUtil.java:352) > at > org.apache.hadoop.yarn.util.ConverterUtils.convertFromYarn(ConverterUtils.java:237) > at > org.apache.hadoop.yarn.client.api.impl.ContainerManagementProtocolProxy$ContainerManagementProtocolProxyData.newProxy(ContainerManagementProtocolProxy.java:218) > at > org.apache.hadoop.yarn.client.api.impl.ContainerManagementProtocolProxy$ContainerManagementProtocolProxyData.<init>(ContainerManagementProtocolProxy.java:196) > at > org.apache.hadoop.yarn.client.api.impl.ContainerManagementProtocolProxy.getProxy(ContainerManagementProtocolProxy.java:117) > at > org.apache.hadoop.mapreduce.v2.app.launcher.ContainerLauncherImpl.getCMProxy(ContainerLauncherImpl.java:403) > at > org.apache.hadoop.mapreduce.v2.app.launcher.ContainerLauncherImpl$Container.launch(ContainerLauncherImpl.java:138) > at > org.apache.hadoop.mapreduce.v2.app.launcher.ContainerLauncherImpl$EventProcessor.run(ContainerLauncherImpl.java:369) > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) > at java.lang.Thread.run(Thread.java:745) > Caused by: java.net.UnknownHostException: 101-master10 > ... 12 more > > > > 15/02/22 20:17:44 INFO > > Regards, > Tariq
