It's supposed to be two separate incidents: power going down in Strasbourg, and fiber network equipment going down in Roubaix (the main center of OVH's network) due to a "software bug".
It's explained here https://twitter.com/olesovhcom/status/928587258583748609 in French, they might post an English-language translation soon.
So, that one datacenter caused all other datacenters to die..?