WDQS servers were schedule for a reboot during the weekly deployment window. While the first server rebooted without issue, things did not go as well with the second one. We do not know yet what the issue is, but we are investigating [1].
This has no direct impact to the end user, we can run on a single server, as long as we don't loose it as well...
[1] https://phabricator.wikimedia.org/T132387