Before You Begin Installing CDH4 Manually
- This section contains instructions for new installations. If you need to upgrade from an earlier release, see Upgrading from CDH3 to CDH4 or Upgrading from an Earlier CDH4 Release.
- For a list of supported operating systems, see CDH4 Requirements and Supported Versions.
- These instructions assume that the sudo command is configured on the hosts where you will be doing the installation. If this is not the case, you will need the root user (superuser) to configure it.
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).)
- 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).
- Cloudera Manager sets the default to Fair Scheduler.
- CDH4 sets the default to Fair Scheduler, with FIFO and Fair Scheduler on the classpath by default.
- MRv2 (YARN):
- Cloudera Manager sets the default to FIFO.
- CDH4 sets the default to FIFO, with FIFO, Fair Scheduler, and Capacity Scheduler on the classpath by default.