Incompatible changes introduced in Cloudera Manager 4.1.2
The alternatives priority of MapReduce 1 MR1 is now higher than that of MR2 (YARN). This means that the MR1 configuration will take priority by default. In previous releases, if both MR1 and MR2 were installed, MR2 took higher priority. To restore the MR2 to a higher priority, go to the Configuration tab of the YARN service, search for "alternatives" and set the priority to a higher value than the equivalent value for MR1. (By default in Cloudera Manager 4.1.2, YARN is set to 91, and MR1 is set to 92).
Cloudera Manager 4.1.2 supports only version 0.3 of the Cloudera Impala Beta Release. It does not support the earlier beta versions. If you upgrade your Cloudera Manager installation, you must also upgrade Impala to beta version 0.3. If you upgrade Impala to beta version 0.3, you must upgrade Cloudera Manager to 4.1.2.