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Carrefour Belgium: leading our move to cloud!
January 31, 2023

With 99,7% of its IT landscape moved to Google’s Cloud Platform, Belgium is the absolute frontrunner within the Carrefour Group when it concerns cloud adoption. This challenging and complex migration journey demonstrates how a dream team’s flaming ambition can shape the foundations of a true DigitalRetail Company. 

Not so long ago, Carrefour Belgium had all of its operations running scattered over its local data center in the basements of its former Evere headquarters, and locally in every store location. 

This had been the case for decades: old-fashioned machines operated by infrastructure engineers. Then, digitization made the heart of retail beat faster. It brought more data, more apps, and an increased load to the data centers. Issues and escalations started to turn into daily occurrences for the tech teams. The data centers were actually having trouble responding to the increasing performance needs. They were also suffering greatly from other problems, such as water infiltration, overheating and humidity.

Life before the cloud journey…

A temporary outage would impact our customers… And a complete failure could potentially result in the shutdown of all of our operations. We needed to modernize our way of running technology. It was crucial for business!

A stronger retail transformation thanks to the cloud

A deep transformation of traditional retail through digital is part of Carrefour’s 2026 strategy and cloud migration is one of the foundations of this plan. The Group is moving forward with one of the fastest infra transformations in retail.

The cloud helps us increase our systems agility and the time-to-market to develop new services and applications. The value extracted from the operational data is reinforced, thanks to the use of artificial intelligence solutions. By adopting a “data-centric, digital-first” culture, we can also drive major changes to traditional business processes including pricing, assortment strategy, activity forecasts, logistics, supply flows… 

This digitization will also contribute to the improvement of the customer experience, with greater personalization, and operational excellence in stores as well as at headquarters. For example, our new point of sale solution SmartPoS runs partially on the cloud. This helps us to monitor the cash registers in a more professional, centralized way, and thus avoid incidents.

Finally, when migrating to the cloud, it’s not only about getting there… But also about what you do when you get there. It means creating an entirely new technology operating model and culture that enables Carrefour to innovate more quickly and efficiently. Our cloud strategy also makes it a lot easier to attract talent. Engineers joining Carrefour tell us that one of the things they like is working in a company with a modern technological foundation.

Making it happen in Carrefour Belgium!

Moving to the cloud is not something that happens overnight. It requires careful analysis, planning, and execution to ensure a smooth transition. In Carrefour Belgium, we decided to approach this migration journey in four phases. 

1 – Stabilize

The first was to quickly stabilize the environment. We moved the local data center to a more solid, still traditional infrastructure (“twins”).

2 – Learn & adapt

At the same time -this was back in 2019-, we launched our pilot of migration to the Google Cloud Platform (GCP). Our “guinea pig” application for the pilot was our promo engine tool. The pilot helped us to test & learn. One of the concrete outcomes of the pilot was to define our target GCP ecosystem, which included a was a mix of IP4G (IBM Power for GCP), GCVE (Google Cloud Vmware Engine), GCE (Google Compute Engine) and GKE Autopilot (Google Kubernetes Engine).

3 – Move

Then, as a third step, we proceeded with the migration of our stores -integrated as well as franchised- and centralized applications to GCP. This was a journey of three years. While centralized applications like SAP moved relatively fast (the essential of it happened in 2021), the journey to migrate store applications was more complex. It took us almost three years to complete it. As a final layer in the migration model, we moved the infrastructure components housed within “twins” to the appropriate infra components in GCP. Personally, I believe this happened at mind boggling speed since the entire shift took less than three months.

4 – Cloud run

And finally, we are now making the final step to take over cloud management by creating and maintaining our own team of cloud superstars, since we are truly convinced that by investing in the growth of our own teams, our own people we will create a competitive advantage for Carrefour. No longer having to share resources with other companies, being able to secure knowledge and gain plenty of other advantages such as financial terms, Intellectual Property allows us to create a real competitive edge.

Carrefour Belgium’s migration roadmap

Achieving stability and gaining experience with Google Cloud

Back in 2019, the solution was found with our partner Kyndryl. We had been working with them for several years so they had all the necessary experience with our systems and needs.

We drafted a plan to migrate core systems to the Kyndryl Tier 3+ hybrid cloud data center (“twins”) in southern Belgium. Where an approach with an intermediate landing seems like a lot of hassle and additional cost at first sight it was a crucial part of the successful roadmap for Belgium given the shape of our own data centers in 2018. 

Continued operations were of utmost importance for us and given the shape of the data centers. When I arrived in my position of CTO of Carrefour Belgium, it became clear very rapidly that the complexity to move everything to a cloud hyperscaler (note we had to move 100% of our infrastructures!) was not possible given certain restrictions within Google’s ability in European data centers. Examples of those limitations are not limited to the availability in Europe of IBM Power machines or ultramem machines for our SAP landscape.

Carrefour Belgium CTO Stijn Stabel visiting one of our former “twins” hybrid data centers

The Kyndryl team completed the work in record time (14 months), migrating 100% of on-premises systems without downtime or disruptions to business operations. A team of knowledgeable, driven and communicative professionals with a sound and long lasting relationship with the internal teams were undoubtedly the key factor of success.

Maxxing: our first cloud pilot

For taking our first baby steps in the cloud we selected Maxxing as our first cloud pilot. Maxxing is our pricing and promotion engine and as such a supercritical and heavily used part of our application landscape. For a reference, the machine is hit with approx 180-250 API calls every second. They cannot suffer from any delays in the process since this will be directly visible at our checkout counters. The Maxxing project team was onboarded and truly excited to make it work. So we set sail for a first success which it was… The machines on GCP or not giving the smallest hiccup under the harshest circumstances!

Time for the big store migration

Store operations were in high need of technical modernization as well. Back then, every store had a small data center, running applications on outdated PCs kept in storage rooms. 

Central management

Our main goal was to ensure we did not have to invest in ~800 small data center locations… Moreover having to ensure continued operations after. Hence the plan after our first success with GCP was to empty all local data centers and replace them with services and servers running under central management in Google’s premises. This should not only provide us with higher levels of availability but also better recovery time objectives at a lower cost.

Process automation

On top of that, we managed to automate the process using a standard service catalog on GCP. This enables franchise store owners to request for a new machine via a service ticket. This will then trigger an automated provisioning via a script created in either Terraform or Ansible. With the same VMs running across the stores, we enabled their front-end and back-end systems to more consistently and efficiently integrate into executing current business operations. Scripted deployment packages are definitely a key to the success of this part of the project. And also to the flexibility we offer to our store owners and business partners to rapidly react to changing needs and conditions in our most important formats.

New services

By centralizing the store compute environment, we are able to react on the spot and tackle issues quickly. We also have the elasticity and flexibility that a cloud environment brings, allowing us to develop new services. We can now create more customer-centric experiences, all at the tips of our fingers in a super transparent and agile way.

To date, we have migrated 100% of our integrated stores on GCP. And more than 99% of the franchised stores, the remaining ones will be shifted during Q1 2023.

Carrefour Express Aalst said goodbye to its local data center and
moved to the Google Cloud on the 20th December 2022

Migrating our entire tech landscape to the cloud

But a retailer is much more than a collection of stores. Carrefour Belgium’s tech landscape consists of more than 450 applications within a wide variety of domains: e-commerce, marketing, warehousing, logistics, finance, HR, data, security and so much more. And yes, we wanted to address all of them!

As significant infrastructure changes might impact an application’s performance, managing risk is a key component in the preparation of a migration strategy. With a thorough assessment of the existing infrastructure, application, and data landscape, we managed to make informed decisions on what to move, when, and how. Google engineering teams in Belgium were our day-to-day partners in this effort. 

For instance, consider SAP. The SAP landscape in Belgium concerns over 100 machines supporting more than 10 landscapes (varying from retail to finance, from a sandpit to production machines). On top, we were forced to deal with complexity like unsupported databases, databases that were (close to) impossible to license in the cloud and application versions no longer supported by SAP. A “walk in the park” so to say… But long story short, thanks to the dedication and perseverance of the different teams, the ability to think out of the box of our partners who accommodate the changes, we managed to pull through and made some huge advancements in the stability and housing of these systems, not to mention the cost model which was a driving factor as well.

Our close collaboration with Google is key for our cloud transformation journey

Cloud, way more than technology!

Our use of the cloud is not just about technology – it’s just as much about collaboration and a cultural shift. 

The way of designing applications is also changing. We now don’t build apps that go along for the next 10 years. It is more about quickly answering changing demands in the market, requiring new, more agile ways of working.

This new deal comes with a lot of challenges. We are proud to say that the hard work paid off! Here are some key takeaways from our “human” journey to the cloud.

Business support

Buy-in from business stakeholders is key! Make sure the business is onboarded early in the process. And know what is expected of them to deliver a successful migration. In my experience, migrations are often exercises taking place on the quiet moments of the day (read night). So a strong commitment from the business to test the soundness of operations before the “real”’ workloads hit is critical to avoid unwanted impacts.


Frame the migration as more than a technical initiative and communicate the added value for the business. Also proactively inform on the planned migration and the possible impact. In our case we learned that in most scenarios, one mail is never enough, one channel never reaching your entire population. A multiformat approach was our key to success. And communication can hardly be overdone in these circumstances was a hard learned lesson.

Build the team

From the very start, we were convinced that our migration would only be successful if we build, train, and retain our own team of cloud engineers. This adventure would have been impossible without rockstars like Pieter Salaets, Kevin Dutoit and Davy Van Kerckhoven and plenty of others that are too much to name. This team now bears the huge responsibility of managing our entire cloud operation! Wondering how we build strong tech teams at Carrefour? Have a look at our previous article on the “Join the retail revolution” campaign.

Join the Retail Revolution

Big thanks to the team for all the hard work, dedication, and commitment. The thank you list would be too long to write. Every contribution, even the ones which seemed small, has been key to making this project a success!

About the Author

CTO Carrefour Belgium Stijn Stabel is the Chief Technology Officer for Carrefour Belgium. He has been a digital transformation expert for 20 years. He loves to re-invent digital and help businesses to innovate. In 2011, he came up with the idea to compete in an “Ironman”, aka a long-distance triathlon (swimming / cycling / running). Three years later, the challenge was completed in such a way he got selected to compete in the world championships Ironman held in Hawaii in 2015! His personal and professional motto: “anything is possible”.

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