Ukraine's drones turned Yandex's AI data centres into targets

Overnight into October 8, drones hit a Yandex data centre in Sasovo, a town in Russia's Ryazan region southeast of Moscow. The building sits on the grounds of the Sasta machine-tool plant. Yandex said the drone attack started a fire and "affected part of the infrastructure". Nobody was hurt. By the evening the site had shut down entirely, and the company said it could not yet say whether the damaged equipment could be saved.

The next night, Yandex lost part of its Kaluga site, the company's largest. Early on October 11, the Vladimir facility east of Moscow went dark too. That is three data centres in four days, all belonging to Russia's biggest technology company. Reuters called the Sasovo strike the first major attack on a Russian data hub. It will not be the last attack on a data centre, in Russia or anywhere else.

What was inside Sasovo

Sasovo was not an ordinary rack farm. Yandex has said the site holds two of its three AI supercomputers, the machines it uses to train YandexGPT, its flagship large language model. Reuters reported that both run on Nvidia A100 processors. They are reportedly named Lyapunov and Chervonenkis. According to the independent science outlet T-invariant, Chervonenkis ranked 19th on the global Top500 list in 2021, the most powerful of the three.

Yandex has declined to say whether either machine was damaged. That is the most important unknown in the story. Fire and water suppression are rarely kind to dense GPU clusters, but no one outside the company has confirmed the hardware's condition. A widely shared claim that thousands of Nvidia GPUs were destroyed comes from open-source analysts, not from Yandex or Reuters. Treat it as unverified.

Vladimir matters for the same reason. According to SOFX's reporting, it housed Galushkin, the third AI-training supercomputer. Yandex has not said whether any machines there were harmed either. If that reporting holds, every location running Yandex's large-scale training hardware has been hit within a single week.

Why the hardware is hard to replace

Russia cannot just order more. Export controls have cut off legitimate supply of advanced Nvidia accelerators to Russia since 2022, so the A100s at Sasovo were bought before the doors closed. Replacing them means grey-market imports, through intermediaries, at a markup and with delays. A source told Kommersant that replacement equipment could take up to six months to arrive.

Kaluga shows what was being built for the future. According to The Insider, construction at the Grabtsevo industrial park began in 2022 and was planned for more than 3,800 server racks and 63 MW of design capacity. Yandex once called it its most powerful data centre in Russia. The company said several modules there were "completely disabled" and did not give a timeline for repairs. SOFX put the Vladimir site at 40 to 50 megawatts.

The outage reached far beyond Yandex

When Sasovo went down, Yandex Cloud's status page listed its ru-central1-b availability zone as completely unavailable and told customers to move their workloads elsewhere. The knock-on effects ran across the Russian internet. Users reported outages at Russian Railways, the mobile operator MegaFon, the classifieds site Avito, T-Bank and several media outlets. The Moscow Times, citing Kommersant, reported that retailers Magnit and M.Video were affected. Outages also spread to Kazakhstan, Kyrgyzstan, Uzbekistan and Armenia.

Inside Yandex, the losses read like a list of everyday Russian digital life: Yandex Go taxis, Maps, Pay, the Alice voice assistant, and the YandexGPT programming interface for business customers. Yandex told taxi drivers to use Google Maps or Waze, a striking admission from a company that built its brand on beating Google at home. Rival cloud providers agreed to help Yandex clients move their data quickly. Yandex shares fell about 4% on the Moscow Exchange after the Kaluga strike.

Yandex Cloud has more than 64,000 customers, according to The Moscow Times. That is the hidden lesson: concentration risk. A handful of large sites carried a large share of a national economy's online services, and the failover capacity was not ready for several sites to go down at once. T-Investments analyst Maryana Lazaricheva told Reuters that Yandex could move some work to its remaining sites, but that "that option will disappear" if the attacks continue.

A war over servers, on both sides

Ukraine framed the strikes as retaliation, and the reason is not hidden. Since late September, Russian strikes have damaged or destroyed data centres belonging to at least eight Ukrainian companies, Meduza reported. One wave cut internet access for about 100,000 households in the Kyiv area. Russia's Defense Ministry described its campaign as "a forced digital detox". Asked about Sasovo, Volodymyr Zelensky said Russia had been hitting Ukrainian data centres, and added: "We hit back."

Moscow says the Yandex sites were used by Ukrainian military intelligence, a claim it has not backed with evidence. Digital development minister Maksut Shadayev called the scale of the attacks "unprecedented" and said his ministry was working with the Defense Ministry on protecting data centres. Russia has already taken a step in that direction. In August, Vladimir Putin gave the state power to seize critical infrastructure judged poorly protected against drones, according to SOFX. Ukraine, for its part, told Reuters it is moving its digital systems underground.

The pattern is not limited to Ukraine. TNW noted that in March, Iran's Revolutionary Guards named 18 US tech firms as military targets, and that the UAE is splitting its Stargate data centre campus after Iran named it as a target.

What to watch

For years, data centres were treated as commercial property with good fire suppression. This week showed they are strategic infrastructure, as targetable as a refinery and much easier to find from power-grid filings and permit records. Yandex had already blurred its cloud sites on its own maps before the strikes, Verstka reported. That did not help.

Three questions now matter. First, whether Yandex confirms damage to the A100 clusters, because that decides whether YandexGPT development stalls for months or only for weeks. Second, whether Russia's answer is hardening, dispersal or seizure under the August law. Third, and most important outside Russia, whether boards and governments planning gigawatt AI campuses start pricing in air defence the way they price in power and water. A single site can hold a nation's frontier compute, and this week showed what happens when that site is within drone range.