Tim Cook, Apple CEO, speaks about new features of the iCloud service during an event at the company's headquarters in Cupertino, California.

An Apple executive responsible for operating data center infrastructure for some internet services -- an increasingly important area for the company -- has left, two sources have told CNBC.

Eric Billingsley, director of internet services operations at Apple, was in charge of operating infrastructure for iCloud services, including the iCloud Drive document storage service that competes with services like Dropbox and Microsoft's OneDrive.

A source close to the situation said that Billingsley's old team is reporting to engineering vice president Patrice Gautier.

Apple declined to comment.

Apple has informed the people under Billingsley -- a veteran of eBay and Google who came to Apple in 2013 -- about his departure, one source said.

Data center infrastructure in the past has been "a bit of a problem child," the source said, and another person who reports to Gautier, Patrick Gates, has been "righting the ship." Gates continues to run infrastructure for some services, including Siri.

Apple in 2015 decided to use Gates' group's infrastructure for more services, including iCloud, The Information reported last year.

Billingsley's organization has relied to a degree on external public cloud providers like Web Services and Azure to handle the computing needs of services like iCloud. A major AWS outage in February impacted Apple Music, iCloud services and iTunes, among other things. Billingsley's exit could signal that Apple plans to depend less on external cloud services and more on its own data center infrastructure as part of its Project McQueen effort.

While devices and specifically the iPhone bring in more revenue than anything else at Apple, internet services have taken on greater importance recently.

In April 2016 Apple began playing up the importance of its services business as iPhone revenue and overall revenue slipped for the first time in years. "Over the last 12 months, our services business has become the size of a Fortune 100 company, a milestone we've reached even sooner than we had expected," Apple CEO Tim Cook said on the company's earnings call in August.

Correction: Billingsley's old team reports to engineering vice president Patrice Gautier, not Patrick Gates, as sources originally told CNBC.