Cloudera Manager - Incompatible clusterIDs Installation error

If you are seeing the following "Incompatible clusterIDs" error during an cluster installation,

Initialization failed for block pool Block pool BP-1040168619-192.168.1.11-1376935066427 (storage id DS-2088750341-192.168.1.11-50010-1376059413438) service to hadoop1/192.168.1.11:8022
java.io.IOException: Incompatible clusterIDs in /dfs/dn: namenode clusterID = cluster64; datanode clusterID = cluster31

it is probably because you are doing an re-installation. At least this is my case. For some reason I had to remove the current existing cluster, and re-install CDH from scratch. During the "HDFS" service installation, I got the above error. After some investigation, I found out that you have to update date the clusterID, make sure datanode and namenode have consistent cluster ID.

You can modify the cluster ID in the following file:
vi /dfs/dn/current/VERSION

You should be fine after modification.