5. Resolving General Problems

 5.1. During Enable Kerberos, the Check Kerberos operation fails.

When enabling Kerberos using the wizard, the Check Kerberos operation fails. In /var/log/ambari-server/ambari-server.log, you see a message: 02:45:44,490 WARN [qtp567239306-238] MITKerberosOperationHandler:384 - Failed to execute kadmin:

 5.1.1. Solution 1:

Check that NTP is running and confirm your hosts and the KDC times are in sync. A time skew as little as 5 minutes can cause Kerberos authentication to fail.

 5.1.2. Solution 2: (on RHEL/CentOS/Oracle Linux)

Check that the Kerberos Admin principal being used has the necessary KDC ACL rights as set in /var/kerberos/krb5kdc/kadm5.acl .

 5.2. Problem: Hive developers may encounter an exception error message during Hive Service Check

MySQL is the default database used by the Hive metastore. Depending on several factors, such as the version and configuration of MySQL, a Hive developer may see an exception message similar to the following one:

An exception was thrown while adding/validating classes) : Specified key was too long; max key length is 767 bytes

 5.2.1. Solution

Administrators can resolve this issue by altering the Hive metastore database to use the Latin1 character set, as shown in the following example: mysql> ALTER DATABASE <metastore.database.name> character set latin1;

 5.3. Problem: API calls for PUT, POST, DELETE respond with a "400 - Bad Request"

When attempting to perform a REST API call, you receive a 400 error response. REST API calls require the "X-Requested-By" header.

 5.3.1. Solution

Starting with Ambari 1.4.2, you must include the "X-Requested-By" header with the REST API calls.

For example, if using curl, include the -H "X-Requested-By: ambari" option. curl -u admin:admin -H "X-Requested-By: ambari" -X DELETE http://<ambari-host>:8080/api/v1/hosts/host1

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