Exit statuses for the HDFS Balancer

THe HDFS Balancer concludes a cluster balancing operation with a specific exit status that indicates whether the operation succeeded or failed, with supporting reasons.

Table 1. Exit Statuses for the HDFS Balancer
Status	Value	Description
`SUCCESS`	0	The cluster is balanced. There are no over or under-utilized storages, with regard to the specified threshold.
`ALREADY_RUNNING`	-1	Another HDFS Balancer is running.
`NO_MOVE_BLOCK`	-2	The HDFS Balancer is not able to schedule a move.
`NO_MOVE_PROGRESS`	-3	All of the scheduled moves have failed for 5 consecutive iterations.
`IO_EXCEPTION`	-4	An IOException occurred.
`ILLEGAL_ARGUMENTS`	-5	An illegal argument in the command or configuration occurred.
`INTERUPTED`	-6	The HDFS Balancer process was interrupted.
`UNFINALIZED_UPGRADE`	-7	The cluster is being upgraded.