Incompatible changes introduced in Cloudera Manager Enterprise Edition 4.5.0
Alert Publisher by default sends alert email to "root@localhost", via port 25 (SMTP) on localhost. This can be configured during the wizard setup, or in the configuration of Management Server/Alert Publisher.
By default, Hive will set hive.warehouse.subdir.inherit.perms to true. This is a minor change of behavior. If this change is undesired, change the configuration in the Hive service. This impacts upgrade in the following scenarios:
CDH3 cluster to CDH4 cluster using Cloudera Manager 4.5
Cloudera Manager upgrade to Cloudera Manager 4.5, where Cloudera Manager is managing a CDH4 cluster
Cloudera Manager 4.5 does not support Internet Explorer 8. Users who cannot or do not wish to upgrade to Internet Explorer 9 should not upgrade to Cloudera Manager 4.5.
The default Java GC options of NameNode, Secondary NameNode, DataNode, JobTracker, and TaskTracker are now set to:
-XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=70 -XX:+CMSParallelRemarkEnabled
Cloudera Manager API v3 (new in 4.5) does not support setting a service's roletype configuration, since that has been replaced by role group. Callers should set the configuration on the appropriate role group instead. Cloudera Manager 4.5 continues to support API v1 and v2. But users who want to upgrade their existing clients to v3 would need to rewrite any roletype configuration calls.