Once T152714 is done, we can begin this process of upgrading the Hadoop cluster to Debian Jessie. We will first add new Hadoop nodes in T152713 as Jessie Hadoop workers, and then incrementally reinstall Trusty Hadoop workers as Jessie. Once that is done, we can reinstall master nodes, analytics1003, and analytics1027. Next quarter we will replace stat1002 and stat1003 with new nodes (T152712), and can install them as Jessie then.

Thing to remember:

• Follow these instructions to add UUIDs to fstab after installing Debian (handy script provided).
• Add a dedicate APT cdh archive section and then only include it on Hadoop/Druid hosts (atm we use thirdparty): T155726