Architecting a Data Lake for Higher Education Student Analytics
One of the keys to identifying timely and impactful actions is having enough raw material to work with. However, this up-to-date information typically lives in the databases that sit behind several different applications. One of the first steps to finding data-driven insights is gathering that information into a single store that an analyst can use without interfering with those applications.
For years, reporting environments have relied on a data warehouse stored in a single, separate relational database management system (RDBMS). But now, due to the growing use of Software as a service (SaaS) applications and NoSQL database options, data may be stored outside the data center and in formats other than tables of rows and columns. It’s increasingly difficult to access the data these applications maintain, and a data warehouse may not be flexible enough to house the gathered information.
For these reasons, reporting teams are building data lakes, and those responsible for using data analytics at universities and colleges are no different. However, it can be challenging to know exactly how to start building this expanded data repository so it can be ready to use quickly and still expandable as future requirements are uncovered. Helping higher education institutions address these challenges is the topic of this post.
About Maryville University
Maryville University is a nationally recognized private institution located in St. Louis, Missouri, and was recently named the second fastest growing private university by The Chronicle of Higher Education. Even with its enrollment growth, the university is committed to a highly personalized education for each student, which requires reliable data that is readily available to multiple departments. University leaders want to offer the right help at the right time to students who may be having difficulty completing the first semester of their course of study. To get started, the data experts in the Office of Strategic Information and members of the IT Department needed to create a data environment to identify students needing assistance.
Critical data sources
Like most universities, Maryville’s student-related data centers around two significant sources: the student information system (SIS), which houses student profiles, course completion, and financial aid information; and the learning management system (LMS) in which students review course materials, complete assignments, and engage in online discussions with faculty and fellow students.
The first of these, the SIS, stores its data in an on-premises relational database, and for several years, a significant subset of its contents had been incorporated into the university’s data warehouse. The LMS, however, contains data that the team had not tried to bring into their data warehouse. Moreover, that data is managed by a SaaS application from Instructure, called “Canvas,” and is not directly accessible for traditional extract, transform, and load (ETL) processing. The team recognized they needed a new approach and began down the path of creating a data lake in AWS to support their analysis goals.
Getting started on the data lake
The first step the team took in building their data lake made use of an open source solution that Harvard’s IT department developed. The solution, comprised of AWS Lambda functions and Amazon Simple Storage Service (S3) buckets, is deployed using AWS CloudFormation. It enables any university that uses Canvas for their LMS to implement a solution that moves LMS data into an S3 data lake on a daily basis. The following diagram illustrates this portion of Maryville’s data lake architecture:
The AWS Lambda functions invoke the LMS REST API on a daily schedule resulting in Maryville’s data, which has been previously unloaded and compressed by Canvas, to be securely stored into S3 objects. AWS Glue tables are defined to provide access to these S3 objects. Amazon Simple Notification Service (SNS) informs stakeholders the status of the data loads.
Expanding the data lake
The next step was deciding how to copy the SIS data into S3. The team decided to use the AWS Database Migration Service (DMS) to create daily snapshots of more than 2,500 tables from this database. DMS uses a source endpoint for secure access to the on-premises database instance over VPN. A target endpoint determines the specific S3 bucket into which the data should be written. A migration task defines which tables to copy from the source database along with other migration options. Finally, a replication instance, a fully managed virtual machine, runs the migration task to copy the data. With this configuration in place, the data lake architecture for SIS data looks like this:
Handling sensitive data
In building a data lake you have several options for handling sensitive data including:
- Leaving it behind in the source system and avoid copying it through the data replication process
- Copying it into the data lake, but taking precautions to ensure that access to it is limited to authorized staff
- Copying it into the data lake, but applying processes to eliminate, mask, or otherwise obfuscate the data before it is made accessible to analysts and data scientists
The Maryville team decided to take the first of these approaches. Building the data lake gave them a natural opportunity to assess where this data was stored in the source system and then make changes to the source database itself to limit the number of highly sensitive data fields.
Validating the data lake
With these steps completed, the team turned to the final task, which was to validate the data lake. For this process they chose to make use of Amazon Athena, AWS Glue, and Amazon Redshift. AWS Glue provided multiple capabilities including metadata extraction, ETL, and data orchestration. Metadata extraction, completed by Glue crawlers, quickly converted the information that DMS wrote to S3 into metadata defined in the Glue data catalog. This enabled the data in S3 to be accessed using standard SQL statements interactively in Athena. Without the added cost and complexity of a database, Maryville’s data analyst was able to confirm that the data loads were completing successfully. He was also able to resolve specific issues encountered on particular tables. The SQL queries, written in Athena, could later be converted to ETL jobs in AWS Glue, where they could be triggered on a schedule to create additional data in S3. Athena and Glue enabled the ETL that was needed to transform the raw data delivered to S3 into prepared datasets necessary for existing dashboards.
Once curated datasets were created and stored in S3, the data was loaded into an AWS Redshift data warehouse, which supported direct access by tools outside of AWS using ODBC/JDBC drivers. This capability enabled Maryville’s team to further validate the data by attaching the data in Redshift to existing dashboards that were running in Maryville’s own data center. Redshift’s stored procedure language allowed the team to port some key ETL logic so that the engineering of these datasets could follow a process similar to approaches used in Maryville’s on-premises data warehouse environment.
The overall data lake/data warehouse architecture that the Maryville team constructed currently looks like this:
Through this approach, Maryville’s two-person team has moved key data into position for use in a variety of workloads. The data in S3 is now readily accessible for ad hoc interactive SQL workloads in Athena, ETL jobs in Glue, and ultimately for machine learning workloads running in EC2, Lambda or Amazon Sagemaker. In addition, the S3 storage layer is easy to expand without interrupting prior workloads. At the time of this writing, the Maryville team is both beginning to use this environment for machine learning models described earlier as well as adding other data sources into the S3 layer.
The solution described in this post resulted from the collaborative effort of Christine McQuie, Data Engineer, and Josh Tepen, Cloud Engineer, at Maryville University, with guidance from Travis Berkley and Craig Jordan, AWS Solutions Architects.