iridium was phabricator, has been replaced by phab1001.
after a grace period, start decom'ing with all the steps.. not yet though
[x] - all system services confirmed offline from production use
[x] - set all icinga checks to maint mode/disabled while reclaim/decommmission takes place.
[x] - remove system from all lvs/pybal active configuration
[x] - any service group puppet/heira/dsh config removed
[x] - remove site.pp (replace with role::spare if system isn't shut down immediately during this process.)
START NON-INTERRUPPTABLE STEPS
[x] - disable puppet on host
[x] - remove all remaining puppet references (include role::spare) https://gerrit.wikimedia.org/r/#/c/366877/
[x] - power down host
[x] - disable switch port
[x] - switch port assignment noted on this task (for later removal) asw-b-eqiad:ge-1/0/16
[x] - remove production dns entries https://gerrit.wikimedia.org/r/#/c/366878/
[x] - puppet node clean, puppet node deactivate, salt key removed
END NON-INTERRUPPTABLE STEPS
 - system disks wiped (by onsite)
 - system unracked and decommissioned (by onsite), update racktables with result
 - switch port configration removed from switch once system is unracked.
 - mgmt dns entries removed.