The Disk Balancer sub-system is local to each DataNode and can be triggered
on distinct hosts in parallel.
The only time you should receive that exception is if the targeted DN's
hdfs-site.xml does not carry the property that enables disk balancer, or
when the DataNode is mid-shutdown/restart.
How have you configured disk balancer for your cluster? Did you follow the
configuration approach presented athttps://blog.cloudera.com/blog/2016/10/how-to-use-the-new-hdfs-intra-datanode-disk-balancer-in-apach...
What is your CDH and CM version?