This article first appeared on Snapt.
Designing for scale is one of the fundamental principles of modern software engineering. However, an organization’s ambition to build scalable applications often exceeds its ability. While it's easy to see the incredible opportunities for scaling up and going global, many do not appreciate the biggest challenges facing development and DevOps teams building scalable apps.
This guide will help you understand and overcome the obstacles to scale.
What Are The Biggest Challenges With Application Scaling?
Performance
Users expect fast, responsive applications that operate without interruption. To ensure maximum performance in production, you must identify when your application achieves saturation and users begin to experience performance problems. Be prepared to invest significant effort in testing every part of your app – every service – to identify those saturation points.
When you have identified your app’s saturation points, determine what improvements you can make. For example, you might be able to simplify the design of your application.
Plan for how the different services in your app will handle an increasing load. Use load balancing when in production to manage app and service performance to ensure the user experience remains consistent and reliable.
When you monitor performance, do not fixate on only one factor but rather consider every aspect of your application to understand where the bottlenecks are and how to adjust the load on the most affected services. Consider the following:
CPU performance
Memory allocation
I/O flows
Data processing
Latency
Disaster Recovery
All applications fail at some point, even those that are planned, designed, and executed well. Your success in delivering global scale to global markets hinges on your ability to recover quickly when failure affects different regions.
Build systems that are resilient to a variety of failures. Make sure you have the capability to recover failed services as fast as possible. Consider the following:
Do you know what failure looks like in each region you serve? What's normal in one region might be unacceptable in another.
Can you effectively monitor application and infrastructure health in a globally distributed system?
Can you redeploy apps to new clouds, availability zones, and services quickly?
Can you deploy loosely or independently coupled software to reduce dependencies?
Do all your systems have redundancy backups for high availability?
Do you have a reliable app services or app delivery platform that handles monitoring, routing, and failover in a multi-cloud, multi-location environment?
Maintenance
You need to update your application continuously to meet the needs of your users and take advantage of changing technologies. If you take too long to develop and deploy improvements, your users might go elsewhere and your customer churn will rise. As you scale up to serve global markets, the pressure on your organization to deliver relevant updates for each region will only intensify.
Design your application and teams for fast and easy maintenance without compromising quality and stability. Consider the following:
Can you build your application using microservices or similar disaggregated architecture to enable you to update each component independently of the others?
Can you automate testing to find problems fast and deploy high-quality code consistently?
Can you adopt a robust testing-in-production methodology, for example, blue-green or canary deployment models?
Meeting The Global Challenge
The bad news is that building and deploying scalable applications is challenging. The good news is that to solve these challenges you don't need specific tools, frameworks, or even budgets. Instead, success at scale depends on adopting the right principles and methodologies.
Isolate dependencies between systems and keep services loosely coupled. Design for simplicity. Automate testing in CI/CD pipelines. These principles will help you deliver apps with consistent performance, reliability, and maintainability at scale.
Finally, make sure that you have the capability to respond quickly to changes in your production environments around the world. For example, when traffic spikes, or when cybersecurity threats come calling, you need to be able to move fast. Adjusting or pivoting a high-scale global deployment manually is not sustainable.
To do this effectively, you need to find suitable technology partners that can monitor global resources and traffic flows, adjust the load, and launch new app services where required. Infrastructure automation and intelligence are critical to delivering modern apps at scale.