Credijusto: Taming Network Configuration Complexity

Executive Summary

Founded in 2015, Credijusto provides asset-backed loans and equipment leases to small and medium-sized enterprises (SMEs). With approximately 300 employees, it has launched several new financial products at better rates, faster delivery, and peerless customer experience when compared to traditional lenders. Its operations are supported by an AWS-based hybrid cloud architecture. Pulumi enabled the company to migrate quickly and easily from Hashicorp Terraform and other legacy configuration tools, which limited their teams’ ability to scale. Using Pulumi has helped Credijusto to migrate from Amazon ECS to Amazon EKS, and to make use of AWS Lambda and Amazon RDS using real programming languages. This enables the company to modernize its infrastructure quickly and cleanly, ensuring reliability and accelerating recovery times when needed. Beyond infrastructure configuration and deployment, Credijusto is going one step further in using the new Pulumi CrossGuard ‘Policy as Code’ capabilities to ensure that engineering teams stand up new services that comply with company standards.

Credijusto logo

About Credijusto

Credijusto is a new generation of credit for emerging markets. It evaluates the financial situation of SMEs and provides personalized service to enable clients to access funding quickly. With national coverage, it has served thousands of companies in Mexico and is growing at a monthly rate of 15%. Through the Credijusto platform, millions of companies can obtain access to credit in a fraction of the time and effort required with traditional banks. Its credit models are focused on the health of each business, focusing on overall performance, rather than considering only the owner’s personal credit history.

Challenges Faced

Credijusto’s high-growth model and accelerated success have led to the rapid expansion of its IT team over time, with many of its solution architects having developed key projects and then moved to other positions. This led to the development of a highly-complex, hybrid cloud model to support its rapidly-growing customer base. Extensive use of Amazon Elastic Container Service (Amazon ECS) preceded a wholesale shift to Amazon Elastic Kubernetes Service (Amazon EKS), requiring additional skill sets and development of new processes. To meet compliance and security requirements, the team needed to manage an Amazon Virtual Private Cloud with multiple subnets and ACLs to isolate services and environments. Finally, legacy deployments needed to be assessed and either retired or updated, adding additional complexity to the environment. For legacy infrastructure slated for replacement, Credijusto needed a solution to standardize the creation of new infrastructure and simplify tracking and reporting for new cloud resources.

Streamlining Version Control, Ensuring Consistency

One of the key benefits Credijusto found when moving from Terraform to Pulumi was the ability to version everything while increasing visibility into precisely what is changing in every update. From changing labels and tags to updating Helm charts, Pulumi empowered IT to keep track of every resource, whether on-premises or in the cloud, for every change they implemented. The fact that Pulumi enabled teams to use their favorite languages instead of domain-specific tools to manage configuration was a game-changer for Credijusto:

“Once you use a familiar programming language to tackle a problem, you see that you can do way more in less time. Pulumi was a natural choice based on the background and skills of our people in DevOps.”"

— Fernando Carlietti, Lead DevOps Engineer, Credijusto.

Pulumi fits perfectly with Credijusto’s dynamic IT environment, enabling developers to build new infrastructure from the ground up rather than “lifting and shifting” legacy configurations. Pulumi also streamlined updates. For example, Credijusto had five legacy ECS clusters defined in AWS CloudFormation, with four production clusters and one staging cluster, and each required a different template. Rather than having to update each Amazon Machine Image (AMI) separately, the team was able to update one and apply it to each stack for all clusters. The team also found that Pulumi facilitates and is well-integrated with AWS best practices, ensuring consistency, scalability, and reliability across teams and infrastructure.

With Pulumi CrossGuard, Credijusto was also able to enforce policies for consistent tagging, naming, and metadata for new resources.

“With Pulumi CrossGuard we can provide reusable infrastructure components to our application teams and ensure that their implementations adhere to company standards.”

— Fernando Carlietti, Lead DevOps Engineer, Credijusto.


Pulumi made network configurations extremely simple and easy to replicate across environments at Credijusto. Below is an example of how Credijusto used Pulumi to configure multiple subnets per availability zone and environment.

In addition to using EKS with Cluster Autoscaler to dynamically scale their Kubernetes clusters, the Credijusto team also took advantage of the Amazon Relational Database Service (RDS) and Amazon Aurora to enable the database for each application to scale with demand.

“Our database setup relies on a dedicated Amazon Aurora cluster for each product. Everything is configured by Pulumi, by a custom resource that we built to create and manage all related resources (credentials, Option Groups, Parameter Groups, Subnets, Security Groups, Policies, etc.). This ensures a standard configuration across all of our databases.”

— Fernando Carlietti, Lead DevOps Engineer, Credijusto.

Credijusto architecture


Adopting Pulumi enabled Credijusto to migrate to managed Kubernetes with EKS. This improved scalability and reduced costs. It also helped the Credijusto team to tame the complexity of their network configurations across environments. Using Pulumi resulted in a 90% reduction in the amount of network configuration that the team had to manage compared to Terraform or CloudFormation-defined configurations. By simplifying configuration and providing engineering with visibility into exactly what will change in each version, the team benefited from increased confidence in their infrastructure updates.

“By using stack references, we ensure that all the dependencies for an application that we deploy in Pulumi are up to date. If I have any changes in a VPC, it’s very easy to cascade that through all the other projects that we manage with Pulumi. When I started using Pulumi for this it was love at first sight.”

— Fernando Carlietti, Lead DevOps Engineer, Credijusto.

Pulumi also helped Credijusto to accelerate the adoption of EKS across the organization, further simplifying their configuration while improving scalability. Finally, Pulumi CrossGuard greatly improves their process of reporting and project cost allocation as new updates are deployed.

Next Steps

Credijusto plans to expand its use of Pulumi to modernize more of its infrastructure and will use it to create abstractions from its current applications. Its target is to have standardized applications (based on language and framework) deployed in a standardized way, meaning that similar resources (Deployment, Service, Ingress, ServiceMonitor, RDS, IAM Roles) will be created in Kubernetes (on-premises) and AWS. Creating modular abstractions will give the company a faster, easier way to bootstrap new applications, lowering the amount of code that teams need to maintain, and ensuring that standards are followed across the organization.

Pulumi makes it easy to configure AWS VPCs and Amazon EKS. Check out the following articles to get started:

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Pulumi's cloud engineering platform brings infrastructure, developer, and security teams together through a unified software engineering process that tames cloud complexity and accelerates innovation. Using the Pulumi platform, teams can build, deploy, and manage modern cloud applications faster and with more confidence, using any language, any architecture and any cloud. Pulumi lets teams build Universal Infrastructure as Code using popular programming languages (Python, JavaScript, TypeScript, Go, .NET/C#, Java) and markup languages (YAML, JSON, CUE). It enables deploying infrastructure and applications together through a unified delivery process. Finally, teams can manage cloud applications with Policy as Code, better visibility, and controls.

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