hi jss this is a test environment so I am not worried about the principal/realm name but thanks for advise. I tried your method of ignoring the error and it does continue on the next screen but fails on the "kerberize cluster" stage with the error shown below . How can I check/reset the "kadmin" credentials? btw It doesn't take any other credential but K/M@TOLLS.DOT.STATE.FL.US in the installation menu , why ? I tried kadmin@TOLLS.DOT.STATE.FL.US but it doesn't like it . [root@hadoop1 ambari-server]# kadmin.local Authenticating as principal root/admin@TOLLS.DOT.STATE.FL.US with password. kadmin.local: listprincs K/M@TOLLS.DOT.STATE.FL.US << this one is the admin ??? host/hadoop1.tolls.dot.state.fl.us@TOLLS.DOT.STATE.FL.US kadmin/admin@TOLLS.DOT.STATE.FL.US kadmin/changepw@TOLLS.DOT.STATE.FL.US kadmin/hadoop1@TOLLS.DOT.STATE.FL.US krbtgt/TOLLS.DOT.STATE.FL.US@TOLLS.DOT.STATE.FL.US here is the error file from the ambari-server log 30 Nov 2016 08:31:09,518 INFO [ambari-client-thread-1512] AmbariManagementControllerImpl:3749 - Received action execution request, clusterName=FDOT_Hadoop, request=isCommand :true, action :null, command :KERBEROS_SERVICE_CHECK, inputs :{}, resourceFilters: [RequestResourceFilter{serviceName='KERBEROS', componentName='null', hostNames=[]}], exclusive: false, clusterName :FDOT_Hadoop 30 Nov 2016 08:31:09,536 WARN [ambari-client-thread-1512] MITKerberosOperationHandler:459 - Failed to execute kadmin: Command: [/usr/bin/kadmin, -s, hadoop1.tolls.dot.state.fl.us, -p, K/M@tolls.dot.state.fl.us, -r, TOLLS.DOT.STATE.FL.US, -q, get_principal K/M@tolls.dot.state.fl.us] ExitCode: 1 STDOUT: Authenticating as principal K/M@tolls.dot.state.fl.us with password. STDERR: kadmin: Cannot find KDC for requested realm while initializing kadmin interface 30 Nov 2016 08:31:09,537 ERROR [ambari-client-thread-1512] KerberosHelperImpl:1861 - Cannot validate credentials: org.apache.ambari.server.serveraction.kerberos.KerberosInvalidConfigurationException: Failed to find a KDC for the specified realm - kadmin: Cannot find KDC for requested realm while initializing kadmin interface ... View more

the connection was failing because the KDC server was not up and running . I followed this link to install and bring the KDC server and then I could pass the connection test . https://gist.github.com/ashrithr/4767927948eca70845db ... View more

the node is up. The Ambari logs are reporting the following: how can I see if the KDC server is up and listening on port 88 ? I installed Kerberos as follows : yum install krb5-server krb5-libs krb5-workstation 29 Nov 2016 14:52:17,878 ERROR [ambari-kdc-verify] KdcConnection:380 - Authentication failed 29 Nov 2016 14:52:17,890 ERROR [ambari-kdc-verify] KdcConnection:380 - Authentication failed 29 Nov 2016 14:52:17,891 WARN [ambari-client-thread-84] KdcServerConnectionVerification:242 - An unexpected exception occurred while attempting to communicate with the KDC server at hadoop1:88 over TCP 29 Nov 2016 14:52:27,892 WARN [ambari-client-thread-84] KdcServerConnectionVerification:252 - Timeout occurred while attempting to to communicate with KDC server at hadoop1:88 over UDP 29 Nov 2016 14:52:27,892 ERROR [ambari-client-thread-84] KdcServerConnectionVerification:115 - Failed to connect to the KDC at hadoop1:88 using either TCP or UDP ... View more

I would love to but its not showing the "accept as answer" option on your message . if the moderators are listening .. can you please accept Ayub's comment as answer ? ... View more

Ah it was the firewall , I installed KDE on the server it self and I can connect to the Atlas server from the local browswer, so port 21000 is being blocked from my laptop to the node running apache server. thanks for all your help ... View more

I tried all browsers and I cant get all from anyone ... View more

I can't telnet to port 21000 from my laptop does it mean this port could be blocked by firewall ? ... View more