Google just scored a huge win against Amazon by landing Apple as a customer

It's only been four months since Google convinced enterprise queen Diane Greene to come lead its fledgling cloud computing business, but she's already scored a second huge coup for Google: landing Apple as a customer. And pulling it away from Amazon.

Apple has reportedly signed a contract worth between $400 million and $600 million to use Google's Cloud Platform, reports CRN's Kevin McLaughlin and Joseph Tsidulko.

It's not clear if that's the annual or total value of the contract, but sources have told CRN that the money is coming from what Apple spends on AWS. While Apple won't quit using AWS altogether, this could cut its spending on AWS by as much as half.

The secretive Apple has never publicly talked about being an AWS customer but its use of AWS, as well as Microsoft's cloud Azure, has been widely reported since at least 2011 and was confirmed by Apple in a security document. Apple uses AWS and Azure for parts of its iCloud services, The New York Times reported.

Last month, Morgan Stanley analyst Brian Nowak estimated that Apple spends about $1 billion a year on AWS. Nowak believes that Apple was planning on cutting those costs with AWS sooner or later at it builds new data centers. Besides iCloud, Apple runs huge data centers for iTunes and the App Store.

Convincing Apple to try Google's cloud is said to be the work of Greene, who has been busy building more partnerships for Google and wooing big names.

This win is especially impressive given Google and Apple's cantankerous history over the mobile computing market the past few years.

This is Greene's second big score: Spotify also announced that it's moving from Amazon to Google last month.

(Meanwhile, Amazon also recently lost Dropbox as a customer, reports Wired, but Dropbox didn't move to Google. It's grown big enough to build and run its own data centers.)

So Google is working hard to shrug off its status as the No. 3 cloud vendor, behind Amazon and Microsoft.

Top Google cloud executive Urs Hölzle says that by 2020, Google could be making more money from cloud computing services than it does from advertising.

Google could not be immediately reached for comment.

Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.