VMware is enhancing its vCloud Air service with pay-as-you-go billing and the network virtualization capabilities of the company's NSX platform.

The company is also adding some new disaster recovery features. It's all part of running in the hybrid cloud race, where VMware hopes to entice enterprises into using its public cloud rather than a big-name alternative such as Amazon Web Services.

vCloud Air is a VMware-run public cloud, but it really targets hybrid-cloud usage. That is, VMware expects vCloud Air to be used mostly as an extension to a private cloud, called upon as a disaster recovery platform or a playground for code development.

Other vendors such as HP are similarly offering clouds, as are service providers, and Cisco is offering its Intercloud service to pool an enterprise's various clouds together. Public cloud services are dominated by Amazon, Google, and Microsoft, but vendors and carriers are hoping their IT brand cachet can help them become alternatives.

"I don't think there is any customer you talk to today who isn't considering public cloud one way or another," says Mathew Lodge, vice president of product marketing for vCloud Air. Of course, VMware would prefer that those customers consider a vSphere-based cloud. "To stay relevant to our customers, we had to have a public cloud."

To continue that relevance, VMware needs to keep adding features — hence, today's announcements.

First, VMware is activating NSX inside vCloud Air. Primarily, this means the cloud will now offer secure microsegmentation, which has emerged as NSX's calling-card application. NSX isolates a virtual machine's traffic by putting a firewall in the hypervisor, meaning every virtual machine essentially gets its own firewall.

NSX will also allow the creation of 200 virtual networks at a time, a nice bragging point considering Amazon lets you create only a handful, Lodge says.

That's because all those virtual connections need to be tracked in forwarding tables. It's a lot to manage, so to keep it simple, cloud service providers will set limits on virtual networks. (That includes VMware; vCloud Air used to cap customers at 10 virtual networks, Lodge says.)

It's been a bit of a wait for these features. VMware announced general availability of NSX in October 2013, and vCloud Air, originally named vCloud Hybrid, was launched two months prior.

A feature that might intrigue some customers is the advent of vCloud Air Virtual Private Cloud OnDemand — a pay-per-use billing model. Most cloud providers offer a subscription model, with customers paying ahead of time for months or years of service.

Technology has advanced to the point where per-minute billing is possible. The catch is that only about 30 percent of the customer base is actually interested in this, Lodge notes. But it would seem to make sense to establish this model, if one assumes that most networking is going to move to the cloud; future applications might be increasingly ephemeral.

"It's also good for proofs-of-concept and testing, where they want to kick the tires," Lodge says.

Signing up for vCloud Air On-Demand, as the service is called, comes with $300 of free service. That's enough to run a couple of virtual machines for about 90 days, Lodge estimates.

Pricing was a sensitive issue in general last year, as the big cloud providers — Google and Amazon, particularly — seemed intent on driving prices down to zero. But "prices have really stabilized in the past six months," Lodge says. "Amazon has stopped matching Google price cuts."

Moreover, some of the price cutting was the result of costs going down, which in turn was the consequence of Moore's Law, Lodge says.

Finally, vCloud Air is getting some enhancements in disaster recovery. VMware is offering native failback support — meaning workloads can be replicated over the cloud, as opposed to VMware handing you a backup disk drive. And the new vRealize Orchestrator provides a way to build automated recovery plans — one more alternative to interacting with vCloud Air via a command-line interface or REST APIs.