While OpenStack's installed base is small compared with Amazon Web Services and other public hyperclouds, OpenStack has attracted power users for which proprietary public clouds are unsuitable.

"There is a necessity to have something other than the public cloud, and OpenStack is the answer," Johan Christenson, founder and CEO of CityNetwork, a European cloud provider, tells Light Reading. "Amazon is not the one vendor for everything, even though they are certainly a great company."

OpenStack fills needs that the proprietary public clouds can't meet. It brings the benefits of the public cloud to companies' own data centers. "The idea of being able to provision and deprovision slices of compute with your own data center is what OpenStack provides," says Dustin Kirkland, who works on the Ubuntu product and strategy for open source software provider Canonical Ltd.

How small is OpenStack? Revenues from the platform will exceed $5 billion by 2020, with CAGR of 35% per year, according to a recent report by 451 Research . Sounds impressive, right? Think again. Net sales for Amazon Web Services Inc. alone were $8.6 billion for the nine months ending September 30. And that's not four years from now -- that's this year. Microsoft Corp. (Nasdaq: MSFT)'s intelligent cloud revenues, which includes revenues from Azure, were $6.4 billion in the quarter ending September 30. OpenStack looks tiny by comparison. (See OpenStack: Small Pond, but the Big Fish Love It, Cloud Lifts Microsoft Stock to Record Height and Amazon Bigger in IaaS Cloud Than Microsoft, Google & IBM Combined.)

But for companies deploying OpenStack, the platform fills a need. (See OpenStack: Small Pond, but the Big Fish Love It.)

For example, PayPal relies extensively on OpenStack to deliver the agility it needs for online financial technology, said Sri Shivananda, PayPal senior vice president and chief technology officer, speaking at the Structure conference in San Francisco in November. "For us to get and stay agile is super-important," he said.

PayPal operates in about 200 markets, with about 100 different currencies, doing an average of $10,900 in transactions per second last quarter. The peak rate last year was $25,000 per second, which PayPal expects to exceed this year, Shivananda said.

To meet those needs, PayPal has developed complex applications, with 2,600 services making up an infrastructure stack on more than 100,000 cores.

Before deploying OpenStack, a PayPal team required up to eight weeks to deploy a new app or service; with OpenStack, that time is reduced to 17 minutes, Shivananda said. The company previously did a big code release every six months; now it does hundreds of releases every day.

"For our scale OpenStack has done well," Shivananda said. "This is a combination of working with the community that contributes code and a sizable engineering team that we hired."

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Vendor independence

Because it is open source, OpenStack provides freedom from vendor lock-in. If a cloud operator uses an OpenStack distro from one vendor and decides after a while it's not working out, it can switch to another vendor's distro, or download the latest version from the OpenStack Foundation.

Because OpenStack is an open source project with a thriving support community, cloud operators can take control of their own destiny.

For example, Walmart is a leading OpenStack implementer, with 170,000 cores running the open source cloud platform. For Walmart, being part of the operator community is one of the chief benefits of deploying OpenStack, says Andrew Mitry, senior distinguished engineer for Strati, Cloud at Walmart.

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