Digital Realty powers global portal and REST APIs using Azure Spring Apps

Powering up datacenters across six continents

It takes a lot of energy to power datacenter facilities, cooling systems, and the customer infrastructures contained within them. These days, many organizations choose to rent colocation space rather than own and operate their own datacenters. The trend has made Digital Realty the largest global provider of cloud- and carrier-neutral datacenter, colocation, and interconnection solutions. As for power consumption, it also leads the datacenter industry in sustainable environmental performance and is the first datacenter company to receive an ENERGY STAR Partner of the Year Award.

Doing things right is how Digital Realty provides a trusted foundation for customers. “We can’t build datacenters fast enough for the demand,” comments Digital Realty Enterprise Architect Devon Yost. That growth puts pressure on the fast-acting company to provide more self-service tools for its customers. As she puts it, “We don’t have time to do things manually. We have to automate.”

Automation enables customers to consume data from Digital Realty and to manage transaction requests. For example, a company might be about to expand into new markets. That means capacity planning, knowing how much power is available to the existing colocation cabinets, and whether there’s enough physical space to scale out.

“Customers want to expand their footprints globally and be able to more easily manage their physical security, billing and invoices, power consumption, and so on. That’s the reason we’re embarking on this journey,” Yost observes.

Because Digital Realty has grown rapidly through acquisitions, there’s no lack of management and monitoring tool sets, along with pockets of data gravity throughout the world. But that was part of the problem. The executive leadership team wanted to create a comprehensive set of APIs that could consolidate feature sets and revolutionize its global business. Then they could phase out redundant legacy solutions, making it easier for customers to do business with Digital Realty. However, for this plan to work, it needed a cloud platform capable of delivering low-latency services, no matter where the customers were located.

As Yost notes, “We operate everywhere except maybe Antarctica.” The company turned to Azure, which continues to build an extensive global footprint. Azure also offers a comprehensive set of national, regional, and industry compliance offerings—an important consideration for any organization providing secure, compliant services for a worldwide clientele.

A fully managed cloud solution for a fast-moving team

The new API platform needs to support 25 million calls per month with a service-level agreement (SLA) of 99.99 percent uptime. “We have an availability requirement of four nines across the entire platform because it will be business-critical for our customers,” she explains.

To achieve that degree of service at scale, the company adopted a flexible, microservices-based architecture. The engineers planned to create approximately 90 microservices but were looking for the right build time and runtime environment. Kubernetes is a popular choice for developing and running microservices, but it takes time to learn and the team wanted to move fast.

“We wanted to start immediately without long runways for setting up infrastructure, network, and Kubernetes clusters,” she recalls. The team chose Azure Spring Apps instead. Developed by Microsoft and VMware, the fully managed service solves many of the common challenges that enterprise developers face when running Spring Boot applications at scale, and it was just what Digital Realty was looking for.

At its core, Azure Spring Apps runs on Azure Kubernetes Service (AKS) and is designed to reduce the complexity and operational overhead of managing Kubernetes. Azure Spring Apps manages dynamic scaling, security patching, out-of-the-box instrumentation for monitoring, and other features that keep developers focused on their apps rather than on the infrastructure.

As Yost sees it, with this architecture, “Azure Spring Apps is at the center, with the REST APIs that are the power of our platform.”

An efficient distributed architecture comes together quickly

The new API platform starts with Spring Boot–based microservices. Developers deploy the code for a Spring Boot app using Azure DevOps pipelines, and Azure Spring Apps automatically wires the app with the Spring service runtime and provides built-in app lifecycle management. Today, about 30 of the planned apps are deployed across two Azure regions, serving Digital Realty’s busiest datacenters. More services and regions are under development.

Even though the developers were new to Azure Spring Apps, they built a working API platform within a few weeks. The first customers were testing the services 90 days later. “We had to move fast!” she states. “The availability of Azure Spring Apps reference architecture reduced our internal cycles of researching architecture options and Spring Cloud feature sets, which allowed us to rapidly determine how we would want to implement and scale globally.” Based on validated best practices, the Azure Spring Apps reference architecture helps organizations accelerate and secure Spring Boot apps in the cloud at scale.

As part of the Azure ecosystem, Azure Spring Apps efficiently binds to other Azure services, including storage, databases, and monitoring. That made it easy for Digital Realty to adopt additional platform as a service (PaaS) capability. For example, the engineers use Azure Key Vault to safely store keys and secrets used by the apps. Azure Monitor provides metrics, logs, and tracing. Azure DevOps supports continuous integration (CI) and continuous deployment (CD), which are key to the automated efficiency that Digital Realty requires.

Another efficient choice is the use of the Azure Spring Apps Autoscale feature, which Yost says “allows us to scale horizontally—quickly and easily.” Autoscale helps applications perform their best when demand changes. Both scale-out and scale-in are supported.

Scalability and resilience are top of mind in this architecture, according to Yost. “One of the biggest concerns we have is latency. We are sourcing data from multiple different public clouds, so we want to make sure that those microservices can reach out and retrieve the datasets that they need so that we can be at a sub-3–millisecond response time.”

An investment in security

The new API platform also works with Digital Realty’s existing cybersecurity investments, such as Rapid7 security tools and Veracode code scanning. “Azure didn’t cause us to change our standards or our standard tools and platforms,” Yost points out. “Azure Spring Apps and the native feature sets are compatible with all these standards and policies.”

For the company, that means a trusted foundation for a new, business-critical platform, where Azure Spring Apps plays a key role. “Overall, we’re trying to move toward an API-driven architecture across all our platforms, so that was another reason we chose Azure Spring Apps,” Yost adds.

Fast connections and network security

The API platform takes advantage of the company’s existing networking investments. For example, a virtual Palo Alto firewall is the next hop for egress from all the Spring Boot applications running in Azure Spring Apps. The Palo Alto firewall setup, and its integration with the company’s existing AppDynamics analytics tools, was a key success of the project. Digital Realty was able to use its preferred tools while supporting interactions between Azure Spring Apps and other systems, whether on-premises or in other virtual networks.

The firewalls are each paired for high-availability. Digital Realty adopted a hub-and-spoke architecture, with two virtual network hubs on Azure, along with other central services that can be accessed by the spoke virtual networks. The hub-spoke network topology is a proven practice for isolating traffic across multiple regions while providing an efficient way to manage common communication and security requirements. The setup incorporates assets that Digital Realty already knows and uses. For example, ingress traffic is managed by Apigee, an API gateway, and Azure Application Gateway, a load-balancing solution in the hub. F5 acts as a central global web application firewall as a service. Egress traffic travels through the hub firewall.

In the spoke virtual networks, Spring Boot microservices run in individual subnets by environment, following National Institute of Standards and Technology segmentation guidelines, and the service runtime runs in another—each with a dedicated Azure Spring Apps cluster.

End-to-end automation for consistency and standardization

Digital Realty’s API platform architecture is fully automated from end to end because, as Yost explains, “We're trying to achieve standardization. It's nearly impossible if apps and infrastructure are not automated and repeatable processes.”

Digital Realty uses Azure Pipelines, one of the services in Azure DevOps, as the main way of automating environments and provisioning resources, building application binaries, and deploying applications. Developers can spin up a new environment for a given region, for a feature, or for servicing—in a matter of minutes. Everything is automated as infrastructure as code (IaC), including the Palo Alto firewall as the next hop for Spring Boot apps running Azure Spring Apps.

To stamp out consistent, repeatable deployments, the developers use Azure Resource Manager templates (ARM templates). “We leverage several sets of ARM templates for deploying new regions globally, including fully automated management of our virtual Palo Alto firewalls at the edge, and a baseline of virtual networking peering rules,” Yost relates.

In addition, the Azure DevOps CI/CD delivery services help Digital Realty quickly deploy updates to existing applications with minimal effort and risk. It’s a big change from the past, when the developers couldn’t easily address customer change requests.

“We're working on integrating Azure DevOps now with more services for end-to-end automation of product releases—for compliance adherence but also ease of promotion,” Yost adds.

An automated future

As a carrier-neutral datacenter provider, Digital Realty serves all kinds of customers—and they all want immediate insights into their datacenters. Ease of integration makes the new API platform simple for customers to adopt and straightforward for Digital Realty to support.

“One thing we really like about Azure Spring Apps is how easy it makes it to establish connections to a wide variety of target sources, including other cloud providers,” Yost observes. And she says that the ease of integration was “excellent.”

For Digital Realty, the new API platform based on Azure Spring Apps brings the company another step closer to its vision of becoming the heart of the internet.