Microsoft Azure, March 3

A six-hour outage, starting at 9:30 am ET, struck the U.S. East data center for Microsoft’s Azure cloud, limiting the availability of Azure cloud services for some North American customers.

A few days later Microsoft disclosed that a cooling system failure was to blame. Malfunctioning building automation controls caused a reduction in airflow, and the subsequent temperature spikes throughout the data center hampered performance of network devices, rendering compute and storage instances inaccessible.
Microsoft ultimately reset the cooling system controllers, and once the temperature fell, engineers power-cycled hardware to resume services.