Cloudera Manager Cannot Complete SSH Connection to add new Hosts | Incompatible JDK

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asked Aug 25, 2017 in Hadoop by admin (4,410 points)
SummaryUpgrade to JDK to a supported version and restart Cloudera Manager to resolve, but if this is not possible, and you must keep the unsupported version on the host, set JAVA_HOME in /etc/default/cloudera-scm-server to point to the new JDK version.
Applies To
  • Add a new host
  • Cloudera Manager
  • SSH connection
When adding new hosts to the cluster, Cloudera Manager fails to complete SSH connection to new hosts.
The Cloudera Manager Server log will show the following:
2016-08-16 16:18:51,561 INFO NodeConfiguratorThread-1-8:net.schmizz.sshj.transport.TransportImpl: Client identity string: SSH-2.0-SSHJ_0_14_0
2016-08-16 16:18:51,567 INFO NodeConfiguratorThread-1-8:net.schmizz.sshj.transport.TransportImpl: Server identity string: SSH-2.0-OpenSSH_5.3
2016-08-16 16:18:51,567 INFO NodeConfiguratorThread-1-8:net.schmizz.sshj.transport.TransportImpl: Disconnected - BY_APPLICATION

On the new host, /var/log/secure logs the following...
Aug 16 16:05:59 hadoop2 sshd[46678]: Accepted password for root from port 45511 ssh2
Aug 16 16:05:59 hadoop2 sshd[46678]: pam_unix(sshd:session): session opened for user root by (uid=0)
Aug 16 16:06:11 hadoop2 sshd[46678]: Received disconnect from 11: disconnected by user




If Cloudera Manager is running on a lower version of Java then what is documented, the SSH connection will fail.
For example, if Cloudera Manager is on 5.8.x and JDK is 1.6, this issue will happen.  
JDK 1.6 is not supported on Cloudera Manager 5.8.x.

  1. Find out which version of Java the CM Server is using by running below command:
    $ ps -ef | grep cmf.Main | awk '{print $8}' | grep -v grep
  2. Upgrade the JDK to a supported version
  3. Restart Cloudera Manager.
Note:  If you must keep the unsupported JDK version on the host, then please make sure to set JAVA_HOME in /etc/default/cloudera-scm-server to point to the new JDK version. For example, you can add below line as the last line in the file:
export JAVA_HOME=/usr/java/jdk1.8.0_77
  1. Complete the Add A Host Wizard.

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