Hue in CDH 6 requires Python 2.7, which is included by default in RHEL 7 compatible operating systems (OSes).

RHEL 6 compatible OSes include Python 2.6. You must install Python 2.7 on all Hue hosts before installing or upgrading to Cloudera Enterprise 6:

RHEL 6

1. Make sure that you have access to the Software Collections Library. For more information, see the Red Hat knowledge base article, How to use Red Hat Software Collections (RHSCL) or Red Hat Developer Toolset (DTS)?.
2. Install Python 2.7:

   sudo yum install python27

3. Verify that Python 2.7 is installed:

   source /opt/rh/python27/enable
   python --version

CentOS 6

1. Enable the Software Collections Library:

   sudo yum install centos-release-scl

2. Install the Software Collections utilities:

   sudo yum install scl-utils

3. Install Python 2.7:

   sudo yum install python27

4. Verify that Python 2.7 is installed:

   source /opt/rh/python27/enable
   python --version

Oracle Linux 6

1. Download the Software Collections Library repository:

   sudo wget -O /etc/yum.repos.d/public-yum-ol6.repo http://yum.oracle.com/public-yum-ol6.repo

2. Edit /etc/yum.repos.d/public-yum-ol6.repo and make sure that enabled is set to 1, as follows:

   [ol6_software_collections]
   name=Software Collection Library release 3.0 packages for Oracle Linux 6 (x86_64)
   baseurl=http://yum.oracle.com/repo/OracleLinux/OL6/SoftwareCollections/x86_64/
   gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
   gpgcheck=1
   enabled=1

   For more information, see Installing the Software Collection Library Utility From the Oracle Linux Yum Server in the Oracle documentation.

3. Install the Software Collections utilities:

   sudo yum install scl-utils

4. Install Python 2.7:

   sudo yum install python27

5. Verify that Python 2.7 is installed:

   source /opt/rh/python27/enable
   python --version