TL;DR: The Analytics Hadoop cluster will be completely down for max 2h on Feb 6th (EU/CET morning) to upgrade all the daemons to Java 8.

Hi everybody,

we are planning to upgrade the Analytics Hadoop cluster to Java 8 on Feb 6th (EU/CET morning) for https://phabricator.wikimedia.org/T166248.

Sadly we can't do a rolling upgrade of all the jvm-based Hadoop daemons since the distribution that we use (Cloudera) suggests to perform the upgrade only after a complete cluster shutdown. This means that for a couple of hours (hopefully a lot less) all the Hadoop based services will be unavailable (Hive, Oozie, HDFS, etc..).

We have tested the new configuration in labs and all the regular Analytics jobs seem to work correctly, so we don't expect major issues after the upgrade, but if you have any question or concern please follow up in the task.

Thanks!

Luca and Andrew (on behalf of the Analytics team)