Datanode does not start due to permission denied

[#1]

Ever come across below error while starting HDFS datanode in unsecure cluster ?

016-12-22 09:00:41,045 INFO  mortbay.log (Slf4jLog.java:info(67)) - Stopped HttpServer2$SelectChannelConnectorWithSafeStartup@localhost:0

2016-12-22 09:00:41,152 INFO  datanode.DataNode (DataNode.java:shutdown(1915)) - Shutdown complete.

2016-12-22 09:00:41,153 ERROR datanode.DataNode (DataNode.java:secureMain(2630)) - Exception in secureMain

java.net.SocketException: Permission denied

        at sun.nio.ch.Net.bind0(Native Method)

        at sun.nio.ch.Net.bind(Net.java:463)

        at sun.nio.ch.Net.bind(Net.java:455)

        at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)

        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)

        at io.netty.channel.socket.nio.NioServerSocketChannel.doBind(NioServerSocketChannel.java:125)

        at io.netty.channel.AbstractChannel$AbstractUnsafe.bind(AbstractChannel.java:475)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.bind(DefaultChannelPipeline.java:1021)

        at io.netty.channel.AbstractChannelHandlerContext.invokeBind(AbstractChannelHandlerContext.java:455)

        at io.netty.channel.AbstractChannelHandlerContext.bind(AbstractChannelHandlerContext.java:440)

        at io.netty.channel.DefaultChannelPipeline.bind(DefaultChannelPipeline.java:844)

        at io.netty.channel.AbstractChannel.bind(AbstractChannel.java:194)

        at io.netty.bootstrap.AbstractBootstrap$2.run(AbstractBootstrap.java:340)

        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:380)

        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)

        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)

        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)

        at java.lang.Thread.run(Thread.java:745)

2016-12-22 09:00:41,157 INFO  util.ExitUtil (ExitUtil.java:terminate(124)) - Exiting with status 1

2016-12-22 09:00:41,159 INFO  datanode.DataNode (LogAdapter.java:info(47)) - SHUTDOWN_MSG:

This error means DataNode is unable to bind to provided socket.

Reason ? This is most like because the http port or other port of DataNode are listening on port < 1024. For e.x http port property is set to as below.

dfs.datanode.http.address=1022

Solution: Change the port something as 50075 which is greater than 1024. DataNode should be able to start with this solution.