When launching the command

/usr/lib/jvm/jre-1.8.0/bin/java -jar /opt/application/jenkins/slave.jar -jnlpUrl http://10.26.56.111:8080/jenkins/computer/slave-01/slave-agent.jnlp

On a user that is not root, the connection fails after a few seconds and the slave tries to connect every 10s without success.

Logs from the slave :

Oct 10 14:45:02 userbxxy02 java: oct. 10, 2016 2:45:02 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:02 userbxxy02 java: INFOS: Terminated
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Locating server among http://10.26.56.111:8080/jenkins/
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Handshaking
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Connecting to 10.26.56.111:6000
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Server reports protocol JNLP3-connect not supported, skipping
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Trying protocol: JNLP2-connect
Oct 10 14:45:12 userbxxy02 java: oct. 10, 2016 2:45:12 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:12 userbxxy02 java: INFOS: Connected
Oct 10 14:45:16 userbxxy02 java: oct. 10, 2016 2:45:16 PM hudson.remoting.SynchronousCommandTransport$ReaderThread run
Oct 10 14:45:16 userbxxy02 java: GRAVE: I/O error in channel channel
Oct 10 14:45:16 userbxxy02 java: java.io.IOException: Unexpected termination of the channel
Oct 10 14:45:16 userbxxy02 java: at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:73)
Oct 10 14:45:16 userbxxy02 java: Caused by: java.io.EOFException
Oct 10 14:45:16 userbxxy02 java: at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2328)
Oct 10 14:45:16 userbxxy02 java: at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2797)
Oct 10 14:45:16 userbxxy02 java: at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:802)
Oct 10 14:45:16 userbxxy02 java: at java.io.ObjectInputStream.<init>(ObjectInputStream.java:299)
Oct 10 14:45:16 userbxxy02 java: at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:48)
Oct 10 14:45:16 userbxxy02 java: at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
Oct 10 14:45:16 userbxxy02 java: at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:59)
Oct 10 14:45:16 userbxxy02 java: oct. 10, 2016 2:45:16 PM hudson.remoting.jnlp.Main$CuiListener status
Oct 10 14:45:16 userbxxy02 java: INFOS: Terminated

A workaround is to first launch that command with root user, then with jenkins user.