It's becoming clear that the public cloud is going to end up as a battle of giants, with only a few contenders able to grapple against current leader Amazon Web Services (AWS). You shouldn't be surprised that Google plans to be one of them.

A couple of years ago, not everyone knew Google even had a cloud. But Google Cloud Platform heads into its annual conference, starting today in San Francisco, with the buzz that comes from some household-name customers. Just keep in mind, though, that Google still has a long way to go to catch AWS, or even Microsoft Azure.

Here's the rundown. Spotify was announced as a customer in February, and a report last week said Apple — a big-deal AWS contract — is using Google's cloud as well. Home Depot is  due to be announced Wednesday, as is Walt Disney Co., according to reports in Reuters and The Wall Street Journal, respectively.

No surprise, then, that Google Cloud is in growth mode. A company blog entry Tuesday said the company is adding 12 regions (i.e., data centers) by the end of 2017. Two are imminent: A Tokyo center is in beta availability, and an Oregon center is en route later this year.

All this activity will make Wednesday's conference quite a stage for Diane Greene, a VMware founder who was named head of Google's cloud operations in November. According to a Bloomberg report, Greene has scolded Google Cloud's staff for being apathetic when it comes to attracting enterprise clients.

AWS probably won't topple easily. Its market share in cloud infrastructure services was 31 percent in 2015, according to Synergy Research. That's compared with 9 percent for Microsoft Azure and 7 percent for IBM Cloud. Google trailed in fourth place with 4 percent.

But the past few months have shown that webscale competitors are only increasing their fervor to take AWS down a peg. Microsoft has built a compelling story with Azure Stack, which extends Azure's reach into an enterprise data center and is getting wide distribution via Windows Server 10.

IBM doesn't want to be forgotten, either. A missive to the press earlier this week reminds us of some recent customer wins. The names don't have the friendly retail familiarity of Google's, but they're still important: AIG, Anthem, and Indostat are among them.

IBM also says it's been stacking that cloud with technology, including what it says is a faster alternative to AWS's Lambda (a feature letting users rent a fraction of a CPU very quickly) — one that also happens to be open.

Google gets its turn to shine today, and the effort it's been putting into cloud and infrastructure-as-a-service (IaaS) will probably pay off in some way. Analysts are sure to be scrutinizing Amazon's next few earnings reports to see if Google, or anybody else, made a dent in AWS — and whether it's large enough to notice.