wikitech.wikimedia.org will be unavailable for a short time on Friday, beginning around 7AM San Francisco time while we apply kernel updates and reboot[1]. Ideally the downtime will only last 5-10 minutes but I've scheduled an hour window on the deploy calendar in case any of the boxes have trouble reviving.
Labs instances and Toollabs services should not be affected. Some alerts may fire during the window as we're planning to reboot one of the monitoring hosts and the effects of that are unpredictable.
In case of emergency, the content of wikitech (minus some images) is always available on the external backup: https://wikitech-static.wikimedia.org/wiki/Main_Page
-Andrew
[1] For the curious (and my future reference), we're rebooting silver, holmium, labcontrol1002, labnet1001, labmon1001