I'd like to reduce the number of moving parts for the upcoming main Kafka cluster upgrade. It will be easier to manage this upgrade if we switch as many things as we can before the actual Kafka version upgrade.
This task is about upgrading to Debian Stretch and Java 8.
# Procedure
```
# On einsteinium
sudo icinga-downtime -d 3600 -r "prep for reimage" -h kafka2001
# On the host
sudo puppet agent --disable "$USER - reimage"
sudo depool
sudo service kafka stop
sudo service eventlogging-service-eventbus stop
# On neodymium
sudo -i wmf-auto-reimage -p T192832 kafka2001.codfw.wmnet
...
```
Log into host mgmt interface console com2, and wait for installer prompt to do manual partitioning.
/ should be ext4 50GB RAID10 across sd[abcd]1. And /srv should be left alone.
(once all nodes have been reimaged, revert https://gerrit.wikimedia.org/r/#/c/429218/)