trying to form a cluster with 2 nodes on ES 5.6.9 on linux environment...the second node is not able to connect to the first one and fails with below exception. Attaching the debug logs of ES startup
org.elasticsearch.transport.ConnectTransportException: [][10.1.99.151:9307] connect_timeout[3s]
at org.elasticsearch.transport.ConnectTransportException.(ConnectTransportException.java:48) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.transport.ConnectTransportException.(ConnectTransportException.java:44) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.transport.netty4.Netty4Transport.connectToChannels(Netty4Transport.java:363) ~[transport-netty4-client-5.6.9.jar:?]
at org.elasticsearch.transport.TcpTransport.openConnection(TcpTransport.java:570) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.transport.TcpTransport.openConnection(TcpTransport.java:117) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.transport.TransportService.openConnection(TransportService.java:361) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.discovery.zen.UnicastZenPing$PingingRound.getOrConnect(UnicastZenPing.java:398) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.discovery.zen.UnicastZenPing$3.doRun(UnicastZenPing.java:507) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:674) ~[elasticsearch-5.6.9.jar:?]
at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) ~[elasticsearch-5.6.9.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1160) [?:1.8.0]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [?:1.8.0]
at java.lang.Thread.run(Thread.java:811) [?:2.9 (11-22-2017)]
Caused by: io.netty.channel.ChannelException: too many channels (max: 1)
at io.netty.channel.ThreadPerChannelEventLoopGroup.nextChild()(Unknown Source) ~[netty-transport-4.1.13.Final.jar:?]