At VMworld 2016, the relationship and challenges of the software-defined data center (SDDC) and the public cloud was highlighted.

During the day one keynote, VMware laid out the vision of its Cross-Cloud Service; the concept is to extend your SDDC to multiple cloud services. Cross-Cloud Service is possible thanks to tight integration with VMware NSX network virtualization features.

SEE: VMworld 2016: VMware pushes hybrid cloud and SDDC with new Cross-Cloud Architecture

NSX in the cloud

During last year’s VMworld, VMware previewed NSX in AWS. By running NSX as a service on instances running on AWS, customers extend traditional networking to the public cloud. As an example, an AWS EC2 instance shares a contiguous IP scheme as your on-premises solution and is treated like any other object in NSX. Firewall administrators have the ability to create firewall rules that work seamlessly from cloud provider to cloud provider.

VMware accomplishes this by running the NSX services on each OS instance. NSX running in multiple clouds provides a foundation for communication across multiple clouds without making changes to the underlying application code. Architects can create designs that span multiple clouds and on-premises resources considering attributes beyond network boundaries. I like to refer to the capability as cloud glue.

NSX across multiple cloud providers works well for applications designed for traditional networking–even containerized applications work well on a traditional network architecture. However, customers looking to take advantage of specific cloud provider capabilities may run into limitations.

SEE: Video: The most important tech underneath VMware’s new Cross-Cloud Architecture

Abstracted cloud infrastructure

NSX allows for extending your SDDC into the public cloud. Using conversion tools or templates, administrators select the most appropriate physical environment for each workload. When the compute resources are specific to the cloud provider, the NSX model breaks. An example of the challenge is serverless computing solutions such as AWS Lambda or Azure Functions.

Both AWS and Microsoft Azure decouples code from specific cloud instances; neither service exposes an OS to the end user. Without access to the underlying OS, the current design is incapable of applying NSX policies to the serverless function. Talking to VMware executives, VMware is aware of the limitation and is working on ways to integrate NSX into both serverless and SaaS-based services.

SEE: Serverless computing: The smart person’s guide

Today, most VMware customers with multiple clouds aren’t looking to deploy advanced concepts such as serverless computing. According to VMware CEO Pat Gelsinger, 50% of enterprise data will reside in the public cloud in five years. The stat is meant to highlight the maturity level of public cloud in the enterprise. VMware believes there’s ample time to figure out serverless while customers begin to understand how containers integrate into the enterprise.

Beyond networking

The networking challenge highlights areas of concern when aggregating cloud services. Cloud providers are implementing value-add services such as database platforms and function-based computing to lock customers into their platforms.

Customers intending to use multiple cloud providers should tread carefully when non-standard features are leveraged. While a service such as Lambda may fulfill an immediate need, it may also hamper a multi-cloud strategy in the future.