Allego scales for EV growth by migrating to Azure Database for PostgreSQL - Flexible Server

Allego is on a mission to meet this challenge, fast-forwarding the transition to sustainable mobility by providing the infrastructure to make EV charging faster, easier, and more convenient across Europe. As the company rapidly expands its network of EV charge points throughout the continent, it’s dealing with fast-paced growth and the need to maintain a dependable infrastructure.

To support this mission, Allego is taking advantage of the most up-to-date tools and technologies available. When it came to making sure its core services were able to meet the data needs of the future, it chose to take advantage of the latest Azure database as a service (DBaaS) offering by migrating to Azure Database for PostgreSQL – Flexible Server.

Providing the infrastructure for a booming market

Allego, a Dutch company founded in 2013, is a leading European EV charging provider. The company currently maintains nearly 31,000 charging sockets, ranging from traditional AC chargers to cutting-edge, high-power chargers capable of ultra-fast charging an EV in mere minutes. The increasing demand for EVs and the supporting charging infrastructure resulted in Allego’s dramatic growth, leading to a successful initial public offering (IPO) in 2022 on the New York Stock Exchange.

Allego’s charging points are essentially large and complex Internet of Things (IoT) devices connected to the EV Cloud platform. The platform manages these devices and supports a myriad of components enabling state-of-the-art EV customer services.

As the European EV market grows at an exponential rate, Allego has seen a matching increase in demand for its charging services and the corresponding need to process the associated transactions. Allego’s Chief Technology Officer (CTO) Alexis Galley explains, “We‘ve seen a growth rate of 40 percent to 50 percent per year. So the number of transactions we need to handle is roughly doubling every two years.”

The customer or EV driver always comes first for Allego, and a seamless charging experience is the company’s top priority. However, in recent years, Allego’s IT team identified two potential issues with its database architecture that could hamper future growth.

The first issue was the looming end of life (EOL) of PostgreSQL version 9.6, which it had originally used when building out its infrastructure. Without ongoing support, Allego’s PostgreSQL 9.6 instances could not support its ongoing needs. “To put it simply,” remembers Olivier Fourel, Allego Head of EV Platform, “we were racing against time and the EOL deadline.”

By early 2020, Allego started an initiative to replace all of its PostgreSQL 9.6 instances before the version’s announced EOL in November 2021. The clock was officially ticking.

The second issue with a potential to interfere with Allego’s continued growth included challenges with using Azure Database for PostgreSQL - Single Server to host its PostgreSQL databases. Although Single Server was a good match when Allego originally designed its architecture, increased growth had highlighted limits within the service—limits to capacity, scalability, operating system (OS), and PostgreSQL version support. Extensive rewriting of its transaction services could alleviate some of these issues, but that would be time consuming and complex, and it would not address the core EOL problem it was facing at the same time.

With these two issues in mind, Allego began work on a plan to upgrade its database infrastructure, without compromising on the quality of its services. This plan had to meet a number of key business requirements, which included avoiding modifications on the service layers, preventing down time, and providing the necessary capabilities to use this new solution as a foundation for future architectural evolution.

To help move forward, Allego reached out to Microsoft through its Unified Support contract to create a joint team of experts. The team’s mission was to design, validate, and implement a detailed upgrade and migration plan, including down-to-the-minute details and extensive mitigation capabilities.

To address the issues with Single Server, Microsoft suggested taking advantage of the newly introduced capabilities of Azure Database PostgreSQL - Flexible Server, a fully managed, more feature-rich alternative that runs fully on Linux.

“Flexible Server came at the right time,” notes Galley. “It was the solution that suited us perfectly.”

In opting to migrate its existing instance to Flexible Server, Allego could achieve its growth goals without reengineering its service layer. But at the same time, it would need to upgrade its PostgreSQL version. Could the team perform these tasks without a massive disruption to EV Cloud and the company’s customers?

With the right solution, you can move mountains (of data)

Due to the complexity of many technical factors involved, this upgrade and migration process could potentially be time consuming, complex, and risky. And, because of the business-critical nature of the systems, it needed to be seamless.

To help with this process, Microsoft suggested using the Azure Database for PostgreSQL Single to Flexible Server Migration tool. This tool, which is currently in private preview (entering public preview soon), provides a hosted migration service that helps simplify, guide, and automate large-scale PostgreSQL database migrations on Azure, while maintaining business continuity. After several iterations and adjustments, the Allego team, in partnership with Microsoft engineers, was able to use the migration tool to prepare every step of the migration plan.

“The Single to Flexible Server Migration tool was really critical for us to ensure a smooth migration,” explains Fourel. “While running the migration, we maintained both the source and target versions online, without any impact on the service in production. Once both instances were synchronized, we simply switched the button.”

Using the tool, Allego performed an online migration of its databases, while avoiding any disruption to its daily business. This involved upgrading its PostgreSQL version from 9.6 to 12 and, in parallel, migrating 30 databases containing terabytes (TB) of data. The whole process took around 44 hours in production on the largest database—but resulted in no downtime.

“We completed the last step of our migration, the cutover, in a few minutes at 5:30 AM,” recalls Fourel, “just before starting our regular workday. Thanks to our asynchronous messaging capabilities, no interruption of service was experienced by our customers.”

The power to drive forward

By adopting Flexible Server, Allego was able to bypass past issues and focus on future improvements.

“Flexible Server doesn’t require adaptation of PostgreSQL to the Windows ecosystem,” Fourel observes. ”This enables better performance and stronger reliability. We are now working on our next evolutions, including taking advantage of partitioning, intelligent scaling, maximizing CPU consumption, and optimization IO performance.”

The increases in scalability and manageability help to ensure that Allego customers will continue to experience reliable charging services, even as demand keeps growing. With this infrastructure component secure, the company looks forward to expanding its network and continuing to advance Europe’s vision of sustainably powered transportation. 

“We can look forward to the future with much more confidence,” Galley adds. “As we multiply the number of transactions we process, we know we can handle it.”

With the migration complete and system maintenance under control, Allego is positioned to tackle the next major evolution of EV Cloud. In partnership with Microsoft, the company plans to continue evolving the platform. High availability across multiple Azure regions is one of the elements of the agenda.

“We worked closely and efficiently with our Microsoft partners and are looking forward to working together on the next major evolutions of our platform,” concludes Fourel.