Hubspot's O'Neill, for example, says the company had to resolve IP domain naming issues. When the company went to add public cloud support, O'Neill had to coordinate which IP addresses would be hosted by the company and which would be under the public vendor's control. It took about a month of working with Amazon and Rackspace, the firm's public cloud infrastructure as a service (IaaS) vendors, he says, but eventually the hybrid cloud was created.
While there are no standards for integrating clouds, Bittman says there are four "centers of gravity" for typical hybrid cloud environments, each of which have pros and cons in terms of facilitating the effort.
One of the centers is based on the dominant private cloud vendor, VMware, whose products enable enterprises to build an array of private clouds.
By its own accounting, VMware is a mainstay for more than 80% of private clouds today, and while VMware does not offer public cloud services itself, it has a network of 94 partners that customers can work with to create hybrid environments.
That's the upside. On the downside, it can be hard to integrate public cloud services from suppliers that are not VMware-centric, and Bittman says some enterprises fear building their whole integrated cloud environment around tools from one supplier.
A second center of gravity, Bittman says, is emerging around the OpenStack model. Started by Rackspace and NASA in 2010, the OpenStack community has grown to include 152-member companies and the project's goal is to create open source standards for cloud computing. Bittman says the project has the promise for creating a more friendly interoperability model for a wide variety of cloud vendors. On the other hand, Bittman says, OpenStack is still relatively immature and unproven. Only time will tell if it can serve as a key standard for building hybrid environments.
The third major center is the dominant public cloud IaaS provider, Amazon, which offers a series of cloud options through Amazon Web Services (AWS). These range from its Elastic Compute Cloud (EC2) to its Simple Storage Service (S3) products. The company is working to support compatibility between its public IaaS offerings and the private clouds enterprises already have, Bittman says. Amazon publishes, for example, its APIs, which simplify the job of integration, he notes.