How CFM built a well-governed and scalable data-engineering platform using Amazon EMR for financial features generation

This post is co-written with Julien Lafaye from CFM.

Capital Fund Management (CFM) is an alternative investment management company based in Paris with staff in New York City and London. CFM takes a scientific approach to finance, using quantitative and systematic techniques to develop the best investment strategies. Over the years, CFM has received many awards for their flagship product Stratus, a multi-strategy investment program with a 20- year track record that delivers decorrelated returns through a diversified investment approach while seeking a risk profile that is less volatile than traditional market indexes. CFM assets under management are now $15 billion.

A traditional approach to systematic investing involves analysis of historical trends in asset prices to anticipate future price fluctuations and make investment decisions. Over the years, the investment industry has grown in such a way that relying on historical prices alone is not enough to remain competitive: traditional systematic strategies progressively became public and inefficient, while the number of actors grew, making slices of the pie smaller—a phenomenon known as alpha decay. In recent years, driven by the commoditization of data storage and processing solutions, the industry has seen a growing number of systematic investment management firms switch to alternative data sources to drive their investment decisions. Publicly documented examples include the usage of satellite imagery of mall parking lots to estimate trends in consumer behavior and its impact on stock prices. Using social network data has also often been cited as a potential source of data to improve short-term investment decisions. To remain at the forefront of quantitative investing, CFM has put in place a large-scale data acquisition strategy.

As the CFM Data team, we constantly monitor new data sources and vendors to continue to innovate. The speed at which we can trial datasets and determine whether they are useful to our business is a key factor of success. Trials are short projects usually taking up to a several months; the output of a trial is a buy (or not-buy) decision if we detect information in the dataset that can help us in our investment process. Unfortunately, because datasets come in all shapes and sizes, planning our hardware and software requirements several months ahead has been very challenging. Some datasets require large or specific compute capabilities that we can’t afford to buy if the trial is a failure. The AWS pay-as-you-go model and the constant pace of innovation in data processing technologies enable CFM to maintain agility and facilitate a steady cadence of trials and experimentation.

In this post, we share how we built a well-governed and scalable data engineering platform using Amazon EMR for financial features generation.

AWS as a key enabler of CFM’s business strategy

We have identified the following as key enablers of this data strategy:

• Managed services – AWS managed services reduce the setup cost of complex data technologies, such as Apache Spark.
• Elasticity – Compute and storage elasticity removes the burden of having to plan and size hardware procurement. This allows us to be more focused on the business and more agile in our data acquisition strategy.
• Governance – At CFM, our Data teams are split into autonomous teams that can use different technologies based on their requirements and skills. Each team is the sole owner of its AWS account. To share data to our internal consumers, we use AWS Lake Formation with LF-Tags to streamline the process of managing access rights across the organization.

Data integration workflow

A typical data integration process consists of ingestion, analysis, and production phases.

CFM usually negotiates with vendors a download method that is convenient for both parties. We see a lot of possibilities for exchanging data (HTTPS, FPT, SFPT), but we’re seeing a growing number of vendors standardizing around Amazon Simple Storage Service (Amazon S3).

 CFM data scientists then look up the data and build features that can be used in our trading models. The bulk of our data scientists are heavy users of Jupyter Notebook. Jupyter notebooks are interactive computing environments that allow users to create and share documents containing live code, equations, visualizations, and narrative text. They provide a web-based interface where users can write and run code in different programming languages, such as Python, R, or Julia. Notebooks are organized into cells, which can be run independently, facilitating the iterative development and exploration of data analysis and computational workflows.

We invested a lot in polishing our Jupyter stack (see, for example, the open source project Jupytext, which was initiated by a former CFM employee), and we are proud of the level of integration with our ecosystem that we have reached. Although we explored the option of using AWS managed notebooks to streamline the provisioning process, we have decided to continue hosting these components on our on-premises infrastructure for the current timeline. CFM internal users appreciate the existing development environment and switching to an AWS managed environment would imply a change to their habits, and a temporary drop in productivity.

Exploration of small datasets is entirely feasible within this Jupyter environment, but for large datasets, we have identified Spark as the go-to solution. We could have deployed Spark clusters in our data centers, but we have found that Amazon EMR considerably reduces the time to deploy said clusters and provides many interesting features, such as ARM support through AWS Graviton processors, auto scaling capabilities, and the ability to provision transient clusters.

 After a data scientist has written the feature, CFM deploys a script to the production environment that refreshes the feature as new data comes in. These scripts often run in a relatively short amount of time because they only require processing a small increment of data.

Interactive data exploration workflow

CFM’s data scientists’ preferred way of interacting with EMR clusters is through Jupyter notebooks. Having a long history of managing Jupyter notebooks on premises and customizing them, we opted to integrate EMR clusters into our existing stack. The user workflow is as follows:

1. The user provisions an EMR cluster through the AWS Service Catalog and the AWS Management Console. Users can also use API calls to do this, but usually prefer using the Service Catalog interface. You can choose various instance types that include different combinations of CPU, memory, and storage, giving you the flexibility to choose the appropriate mix of resources for your applications.
2. The user starts their Jupyter notebook instance and connects to the EMR cluster.
3. The user interactively works on the data using the notebook.
4. The user shuts down the cluster through the Service Catalog.

Solution overview

The connection between the notebook and the cluster is achieved by deploying the following open source components:

• Apache Livy – This service that provides a REST interface to a Spark driver running on an EMR cluster.
• Sparkmagic – This set of Jupyter magics provides a straightforward way to connect to the cluster and send PySpark code to the cluster through the Livy endpoint.
• Sagemaker-studio-analytics-extension – This library provides a set of magics to integrate analytics services (such as Amazon EMR) into Jupyter notebooks. It is used to integrate Amazon SageMaker Studio notebooks and EMR clusters (for more details, see Create and manage Amazon EMR Clusters from SageMaker Studio to run interactive Spark and ML workloads – Part 1). Having the requirement to use our own notebooks, we initially didn’t benefit from this integration. To help us, the Amazon EMR service team made this library available on PyPI and guided us in setting it up. We use this library to facilitate the connection between the notebook and the cluster and to forward the user permissions to the clusters through runtime roles. These runtime roles are then used to access the data instead of instance profile roles assigned to the Amazon Elastic Compute Cloud (Amazon EC2) instances that are part of the cluster. This allows more fine-grained access control on our data.

The following diagram illustrates the solution architecture.

Set up Amazon EMR on an EC2 cluster with the GetClusterSessionCredentials API

A runtime role is an AWS Identity and Access Management (IAM) role that you can specify when you submit a job or query to an EMR cluster. The EMR get-cluster-session-credentials API uses a runtime role to authenticate on EMR nodes based on the IAM policies attached runtime role (we document the steps to enable for the Spark terminal; a similar approach can be expanded for Hive and Presto). This option is generally available in all AWS Regions and the recommended release to use is emr-6.9.0 or later.

Connect to Amazon EMR on the EC2 cluster from Jupyter Notebook with the GCSC API

Jupyter Notebook magic commands provide shortcuts and extra functionality to the notebooks in addition to what can be done with your kernel code. We use Jupyter magics to abstract the underlying connection from Jupyter to the EMR cluster; the analytics extension makes the connection through Livy using the GCSC API.

On your Jupyter instance, server, or notebook PySpark kernel, install the following extension, load the magics, and create a connection to the EMR cluster using your runtime role:

pip install sagemaker-studio-analytics-extension
%load_ext sagemaker_studio_analytics_extension.magics
%sm_analytics emr connect --cluster-id j-XXXXXYYYYY --auth-type Basic_Access --language python --emr-executiojn-role-arn

Production with Amazon EMR Serverless

CFM has implemented an architecture based on dozens of pipelines: data is ingested from data on Amazon S3 and transformed using Amazon EMR Serverless with Spark; resulting datasets are published back to Amazon S3.

Each pipeline runs as a separate EMR Serverless application to avoid resource contention between workloads. Individual IAM roles are assigned to each EMR Serverless application to apply least privilege access.

To control costs, CFM uses EMR Serverless automatic scaling combined with the maximum capacity feature (which defines the maximum total vCPU, memory, and disk capacity that can be consumed collectively by all the jobs running under this application). Finally, CFM uses an AWS Graviton architecture to optimize even more cost and performance (as highlighted in the screenshot below).

After some iterations, the user produces a final script that is put in production. For early deployments, we relied on Amazon EMR on EC2 to run those scripts. Based on user feedback, we iterated and investigated for opportunities to reduce cluster startup times. Cluster startups could take up to 8 minutes for a runtime requiring a fraction of that time, which impacted the user experience. Also, we wanted to reduce the operational overhead of starting and stopping EMR clusters.

Those are the reasons why we switched to EMR Serverless a few months after its initial release. This move was surprisingly straightforward because it didn’t require any tuning and worked instantly. The only drawback we have seen is the requirement to update AWS tools and libraries in our software stacks to incorporate all the EMR features (such as AWS Graviton); on the other hand, it led to reduced startup time, reduced costs, and better workload isolation.

At this stage, CFM data scientists can perform analytics and extract value from raw data. Resulting datasets are then published to our data mesh service across our organization to allow our scientists to work on prediction models. In the context of CFM, this requires a strong governance and security posture to apply fine-grained access control to this data. This data mesh approach allows CFM to have a clear view from an audit standpoint on dataset usage.

Data governance with Lake Formation

A data mesh on AWS is an architectural approach where data is treated as a product and owned by domain teams. Each team uses AWS services like Amazon S3, AWS Glue, AWS Lambda, and Amazon EMR to independently build and manage their data products, while tools like the AWS Glue Data Catalog enable discoverability. This decentralized approach promotes data autonomy, scalability, and collaboration across the organization:

• Autonomy – At CFM, like at most companies, we have different teams with difference skillsets and different technology needs. Enabling teams to work autonomously was a key parameter in our decision to move to a decentralized model where each domain would live in its own AWS account. Another advantage was improved security, particularly the ability to contain the potential impact area in the event of credential leaks or account compromises. Lake Formation is key in enabling this kind of model because it streamlines the process of managing access rights across accounts. In the absence of Lake Formation, administrators would have to make sure that resource policies and user policies align to grant access to data: this is usually considered complex, error-prone, and hard to debug. Lake Formation makes this process a lot less complicated.
• Scalability – There are no blockers that prevent other organization units from joining the data mesh structure, and we expect more teams to join the effort of refining and sharing their data assets.
• Collaboration – Lake Formation provides a sound foundation for making data products discoverable by CFM internal consumers. On top of Lake Formation, we developed our own Data Catalog portal. It provides a user-friendly interface where users can discover datasets, read through the documentation, and download code snippets (see the following screenshot). The interface is tailor-made for our work habits.

Lake Formation documentation is extensive and provides a collection of ways to achieve a data governance pattern that fits every organization requirement. We made the following choices:

• LF-Tags – We use LF-Tags instead of named resource permissioning. Tags are associated to resources, and personas are given the permission to access all resources with a certain tag. This makes scaling the process of managing rights straightforward. Also, this is an AWS recommended best practice.
• Centralization – Databases and LF-Tags are managed in a centralized account, which is managed by a single team.
• Decentralization of permissions management – Data producers are allowed to associate tags to the datasets they are responsible for. Administrators of consumer accounts can grant access to tagged resources.

Conclusions

In this post, we discussed how CFM built a well-governed and scalable data engineering platform for financial features generation.

Lake Formation provides a solid foundation for sharing datasets across accounts. It removes the operational complexity of managing complex cross-account access through IAM and resource policies. For now, we only use it to share assets created by data scientists, but plan to add new domains in the near future.

Lake Formation also seamlessly integrates with other analytics services like AWS Glue and Amazon Athena. The ability to provide a comprehensive and integrated suite of analytics tools to our users is a strong reason for adopting Lake Formation.

Last but not least, EMR Serverless reduced operational risk and complexity. EMR Serverless applications start in less than 60 seconds, whereas starting an EMR cluster on EC2 instances typically takes more than 5 minutes (as of this writing). The accumulation of those earned minutes effectively eliminated any further instances of missed delivery deadlines.

If you’re looking to streamline your data analytics workflow, simplify cross-account data sharing, and reduce operational overhead, consider using Lake Formation and EMR Serverless in your organization. Check out the AWS Big Data Blog and reach out to your AWS team to learn more about how AWS can help you use managed services to drive efficiency and unlock valuable insights from your data!

About the Authors

Julien Lafaye is a director at Capital Fund Management (CFM) where he is leading the implementation of a data platform on AWS. He is also heading a team of data scientists and software engineers in charge of delivering intraday features to feed CFM trading strategies. Before that, he was developing low latency solutions for transforming & disseminating financial market data. He holds a Phd in computer science and graduated from Ecole Polytechnique Paris. During his spare time, he enjoys cycling, running and tinkering with electronic gadgets and computers.

Matthieu Bonville is a Solutions Architect in AWS France working with Financial Services Industry (FSI) customers. He leverages his technical expertise and knowledge of the FSI domain to help customer architect effective technology solutions that address their business challenges.

Joel Farvault is Principal Specialist SA Analytics for AWS with 25 years’ experience working on enterprise architecture, data governance and analytics, mainly in the financial services industry. Joel has led data transformation projects on fraud analytics, claims automation, and Master Data Management. He leverages his experience to advise customers on their data strategy and technology foundations.