This is the documentation for CDH 4.6.0.
Documentation for other versions is available at Cloudera Documentation.

Before You Begin Installing CDH4 Manually

  Note: Running Services

When starting, stopping and restarting CDH components, always use the service (8) command rather than running scripts in /etc/init.d directly. This is important because service sets the current working directory to / and removes most environment variables (passing only LANG and TERM) so as to create a predictable environment in which to administer the service. If you run the scripts in/etc/init.d, any environment variables you have set remain in force, and could produce unpredictable results. (If you install CDH from packages, service will be installed as part of the Linux Standard Base (LSB).)

  Important:
  • Java Development Kit: if you have not already done so, install the Oracle Java Development Kit (JDK); see Java Development Kit Installation.
  • Scheduler defaults: note the following differences between MRv1 and MRv2 (YARN).Scheduler defaults: note the following differences between MRv1 and MRv2 (YARN).
    • MRv1:
      • Cloudera Manager sets the default to FIFO.
      • CDH 4 sets the default to FIFO, with FIFO, Fair Scheduler, and Capacity Scheduler on the classpath by default.
    • MRv2 (YARN):
      • Cloudera Manager sets the default to Fair Scheduler.
      • CDH 4 sets the default to Fair Scheduler, with FIFO and Fair Scheduler on the classpath by default.
      • YARN does not support Capacity Scheduler.