A Ukrainian drone attack has knocked out a Russian datacenter, and Yandex says bringing the affected cloud region back into operation may not be possible.

Russian web giant Yandex says one of its cloud availability zones is unavailable following a drone attack. Often described as Russia's rough equivalent of Google, Yandex dominates the local market for search, email, and mapping services. The company also operates a cloud computing service whose status page says its ru-central1-b availability zone is down.

"The incident was caused by a fire caused by a drone attack on Yandex's data center in Sasovo, which affected part of the Yandex Cloud infrastructure. Data center operations have been completely halted," the company said.

Sasovo is a town around 300 kilometers southeast of Moscow. Yandex later recommended that users employ unspecified "alternative service restoration plans," including its own bare metal servers, but advised that "it will not be possible to restore service in the near future."

The Russian company has not commented on the source of the drone attack. Ukrainian press reports that President Volodymyr Zelensky has said Russia has attacked Ukrainian datacenters and that his government always responds in kind. Reuters reports that Yandex is uncertain whether it can restore operations at the datacenter.

If Yandex must write off the facility, it will be the second cloud provider to lose facilities to drone attacks this year, after AWS decided its Bahrain facility could not be recovered following an Iranian drone attack. Iran struck AWS facilities because it believed the cloud giant hosts workloads for the US military and its suppliers, and that an attack could therefore disrupt hostilities.

For years, industry executives have told The Register that datacenters are critical infrastructure and will therefore likely become targets for kinetic attacks during conflict, either directly or by attacking their connections to energy grids and communications services. Cloud providers and pundits alike advise using multiple, geographically dispersed availability zones, and cloud suppliers, to improve resilience. That advice is less potent in Russia, where sanctions mean local businesses aren't welcome in clouds across the border. Russia also has a smaller pool of cloud operators to choose from.

Update, 1230 UTC: Yandex has just confirmed that a second datacenter has been struck. It looks like Ukraine is going after more critical infrastructure.