Today managed cloud and hosting provider Rackspace made a big announcement: It will provide commercial support for companies that wish to run their applications on Microsoft's Azure public cloud. Rackspace stock jumped by about 3 percent following reports on the news.

That's because Microsoft is one of the top three public clouds around at the moment, right up there with market leader Amazon Web Services and the emergent Google Cloud Platform. Investors have been wondering when Rackspace would become less stubbornly independent and start providing its widely touted "fanatical support" for the clouds that big companies are increasingly relying on.

Not that Rackspace has never worked with Microsoft. In a statement today Rackspace pointed out that it has collaborated with Microsoft for 13 years and that it is "a five-time Microsoft Hosting Partner of the Year." But now companies can buy Microsoft infrastructure and support directly through Rackspace.

Rackspace found itself stumbling in the cloud world in the past couple of years. Last year the company disclosed that it had tapped Morgan Stanley to help it field partnership and acquisition proposals. But some companies, like IBM, clearly weren't interested in buying Rackspace. Within a couple of months of the disclosure, Rackspace came out with a new pricing model that emphasized the value-added services that the company could provide on top of basic cloud infrastructure.

Rackspace has not officially announced that it will provide support for deployments on Amazon -- but that may well be next.