@Yassine Alternative of telnet can be "netcat" as following: # nc -v 10.166.54.12 8020 # nc -v $REMOTE_NN_HOSTNAME 8020 . Also please check of on the remote NameNode if this port 8020 is actually bound to 0.0.0.0 address (or 10.166.54.12) or some other address? Following command we need to run on the host which has IP Address 10.166.54.12 to know if the port 8020 is actually opened and listening on which IP Address? # netstat -tnlpa | grep 8020<br> . ... View more

@Yassine Can you please try two things. (I am assuming that you are running HDFS command from secure cluster Node to connect to Non secure NameNode hence in that case we do not need to have kerberos ticket, But if it is vice-versa then we will need to have kerberos ticket as well) 1. Please make sure that the remote clusters IP Address (and Hostname) and port is accessible ? (this is to isolate firewall blocking issue) # telnet 10.166.54.12 8020 # telnet $REMOTE_NN_HOSTNAME 8020 2. Please try to specify the "--config" parameter to poiint to a directory where you have kept the HDFS configuration file of remote cluster. # hadoop --config /PATH/TO/Remote_Clusters fs -ls / Here please replace the "/PATH/TO/Remote_Clusters" with the path where you have kept the "hdfs-site.xml" and "core-site.xml" file of remote cluster. . ... View more

@Amira khalifa Please check if the JAR is ok (not corrupted) and it contains the "org.postgresql.Driver" class, you can do so by listing the JAR contents as following: # su - nifi # jar -tvf /home/smadmin/jdbc/postgresql-42.2.1.jar | grep Driver.class Also please check the permission of the JAR to findout if the "nifi" user is able to read that JAR? And if the PATH is correct? # ls -l /home/smadmin/jdbc/postgresql-42.2.1.jar . ... View more

@Amira khalifa Can you please share the exact error that you are getting? Are you getting the Postgres Driver related errors while configuring the DBCP connection pooling in Nifi? If Yes, then please check if you have defined the "Database Driver Jar Url" property with the absolute path to you "postgresqlxxxx-jdbc4.jar" JDBC driver jar file. Also please check that this JAR has proper read permission for the Nifi user. Example: file:///usr/share/java/postgresql94-jdbc.jar file:///c:/postgresql94-jdbc.jar Also if you are managing your HDF cluster suing Ambari then you also might want to see the "--jdbc-driver" option to know how to setup postgresql JDBC driver. https://docs.hortonworks.com/HDPDocuments/HDF3/HDF-3.1.0/bk_installing-hdf-and-hdp/content/setup_options.html . ... View more

@Michael Bronson Yes, your steps looks correct: 0. Stop ambari-server # ambari-server stop 1. Change the PATH for those 3 properties mentioned in the ambari.properties file. pid.dir=/var/ambari-server bootstrap.dir=/var/ambari-server/bootstrap recommendations.dir=/var/ambari-server/stack-recommendations<br> 2. Run the "ambari-server setup" and during the ambari-server setup process, when prompted to Customize user account for ambari-server daemon?, choose y (Please do not change any other properties) NOTE: Just to avoid any mistakes it is always better to take ambari DB dump (just to make sure that by mistake we do not make any other db changes) 3. Then restart ambari-server. # ambari-server start . ... View more

@Michael Bronson In some cases, we might see that once we reboot the ambari server host then this directory is getting created again with "root:root" permissions. This can happen, if by any chance if the "pid.dir" or "recommendations.dir" is mounted on "tmpfs" then rebooting the host might alter the permissions back to 'root:root' and hence the non root ambari user will again not be able to write to these directories. Please NOTE that if you face such issue of getting the permission changed for these directories then please change the values "pid.dir", "bootstrap.dir" and "recommendations.dir" insife ambari.properties file to point to a directory which is not on tmpfs. Like "/var/ambari-server" shouldn't be deleted by the operating system after host reboot. So in such scenarios moving the directories under non tmpfs and re-running ambari-server setup is the best option. ... View more

@ASIF Khan Please refer to the following links to know more about Shiro Authentication and roles: https://zeppelin.apache.org/docs/0.6.2/security/shiroauthentication.html ... View more