4.1. 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 
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; 4.2. Problem: API calls for PUT, POST, DELETE respond with a "400 - Bad Request" 
Removing a registered host not added to a cluster. curl command and REST API calls
                require a header element.
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 4.3. Problem: Nagios alerts for CPU utilization show as UNKNOWN 
Alerts for Master components such as "NameNode CPU Utilization" and "ResourceManager CPU Utilization" show as "UNKNOWN".
Nagios uses Simple Network Management Protocol (SNMP) to check CPU
                    utilization. Be sure SNMP is started and port 161 is accessible between the
                    Nagios Server and the hosts running the Master components.
                    
service snmpd start