How to Overcome Legacy Application Issues

𝗠𝗼𝗱𝗲𝗿𝗻𝗶𝘇𝗶𝗻𝗴 𝗟𝗲𝗴𝗮𝗰𝘆 𝗔𝗽𝗽𝗹𝗶𝗰𝗮𝘁𝗶𝗼𝗻𝘀 𝘄𝗶𝘁𝗵 𝗔𝗪𝗦: 𝗟𝗲𝘀𝘀𝗼𝗻𝘀 𝗟𝗲𝗮𝗿𝗻𝗲𝗱 Legacy applications can hold your business back: high maintenance costs, scalability challenges, and lack of agility. Modernizing with AWS offers a chance to unlock innovation, but it’s not without challenges. Here are some hard-earned lessons I’ve learned along the way: 1️⃣ 𝗕𝗿𝗲𝗮𝗸 𝗗𝗼𝘄𝗻 𝘁𝗵𝗲 𝗠𝗼𝗻𝗼𝗹𝗶𝘁𝗵 𝗦𝘁𝗲𝗽-𝗯𝘆-𝗦𝘁𝗲𝗽 Trying to refactor everything at once? That’s a recipe for disaster.  Instead, adopt an incremental approach: • Start by identifying business-critical components. • Migrate to microservices in stages using containers (ECS, EKS). • Introduce APIs gradually to reduce tight coupling. 2️⃣ 𝗖𝗵𝗼𝗼𝘀𝗲 𝘁𝗵𝗲 𝗥𝗶𝗴𝗵𝘁 𝗔𝗪𝗦 𝗦𝗲𝗿𝘃𝗶𝗰𝗲𝘀 AWS offers countless services, but not all are the right fit. Select based on your workload needs: • 𝗖𝗼𝗺𝗽𝘂𝘁𝗲: Lambda for event-driven tasks, ECS/EKS for containerized workloads. • 𝗦𝘁𝗼𝗿𝗮𝗴𝗲: S3 for static content, RDS or Aurora for relational workloads. • 𝗠𝗲𝘀𝘀𝗮𝗴𝗶𝗻𝗴: SQS and EventBridge for decoupling components. 3️⃣ 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗲 𝗘𝘃𝗲𝗿𝘆𝘁𝗵𝗶𝗻𝗴 Manual deployments and configurations increase complexity and risk. Use: • 𝗜𝗻𝗳𝗿𝗮𝘀𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗲 𝗮𝘀 𝗖𝗼𝗱𝗲 (𝗜𝗮𝗖): Terraform or AWS CloudFormation to define environments. • 𝗖𝗜/𝗖𝗗 𝗣𝗶𝗽𝗲𝗹𝗶𝗻𝗲𝘀: Automate testing and deployment with AWS CodePipeline. • 𝗠𝗼𝗻𝗶𝘁𝗼𝗿𝗶𝗻𝗴: CloudWatch and X-Ray to gain visibility and ensure performance. 4️⃣ 𝗕𝗮𝗹𝗮𝗻𝗰𝗲 𝗖𝗼𝘀𝘁 𝗮𝗻𝗱 𝗣𝗲𝗿𝗳𝗼𝗿𝗺𝗮𝗻𝗰𝗲 Modernization doesn’t mean throwing money at the cloud. Optimize costs by: • Right-sizing EC2 instances or shifting to serverless where possible. • Using Savings Plans and auto-scaling to keep costs under control. • Leveraging AWS Cost Explorer to identify waste and optimize spending. 5️⃣ 𝗜𝗻𝘃𝗼𝗹𝘃𝗲 𝗦𝘁𝗮𝗸𝗲𝗵𝗼𝗹𝗱𝗲𝗿𝘀 𝗘𝗮𝗿𝗹𝘆 Modernization is not just a tech initiative; it’s a business transformation. Engage teams early to align goals and expectations across development, operations, and leadership. 6️⃣ 𝗙𝗼𝗰𝘂𝘀 𝗼𝗻 𝗤𝘂𝗶𝗰𝗸 𝗪𝗶𝗻𝘀 A successful modernization effort starts small, proves value, and expands. Identify low-risk, high-impact areas to deliver quick wins and build momentum. 💡 𝗣𝗿𝗼 𝗧𝗶𝗽: Modernization is an ongoing journey, not a one-time project. Continuously monitor, optimize, and adapt to stay ahead. What modernization challenges have you faced? #AWS #awscommunity

Exactly a year ago, we embarked on a transformative journey in application modernization, specifically harnessing generative AI to overhaul one of our client’s legacy systems. This initiative was challenging yet crucial for staying competitive: - Migrating outdated codebases - Mitigating high manual coding costs - Integrating legacy systems with cutting-edge platforms - Aligning technological upgrades with strategic business objectives Reflecting on this journey, here are the key lessons and outcomes we achieved through Gen AI in application modernization: [1] Assess Application Portfolio. We started by analyzing which applications were both outdated and critical, identifying those with the highest ROI for modernization.  This targeted approach helped prioritize efforts effectively. [2] Prioritize Practical Use Cases for Generative AI. For instance, automating code conversion from COBOL to Java reduced the overall manual coding time by 60%, significantly decreasing costs and increasing efficiency. [3] Pilot Gen AI Projects. We piloted a well-defined module, leading to a 30% reduction in time-to-market for new features, translating into faster responses to market demands and improved customer satisfaction. [4] Communicate Success and Scale Gradually. Post-pilot, we tracked key metrics such as code review time, deployment bugs, and overall time saved, demonstrating substantial business impacts to stakeholders and securing buy-in for wider implementation. [5] Embrace Change Management. We treated AI integration as a critical change in the operational model, aligning processes and stakeholder expectations with new technological capabilities. [6] Utilize Automation to Drive Innovation. Leveraging AI for routine coding tasks not only freed up developer time for strategic projects but also improved code quality by over 40%, reducing bugs and vulnerabilities significantly. [7] Opt for Managed Services When Appropriate. Managed services for routine maintenance allowed us to reallocate resources towards innovative projects, further driving our strategic objectives. Bonus Point: Establish a Center of Excellence (CoE). We have established CoE within our organization. It spearheaded AI implementations and established governance models, setting a benchmark for best practices that accelerated our learning curve and minimized pitfalls. You could modernize your legacy app by following similar steps! #modernization #appmodernization #legacysystem #genai #simform — PS. Visit my profile, Hiren Dhaduk, & subscribe to my weekly newsletter: - Get product engineering insights. - Catch up on the latest software trends. - Discover successful development strategies.

Legacy code: it’s a mess. No one wants to touch it. But it pays the bills. You open a file and it’s like walking into a maze: → No comments. → 300-line functions. → Variable names like ‘temp3’ and ‘doSomething()’. It’s a nightmare. But here’s the reality: most of us don’t get to start fresh. The code works, and rewriting it isn’t practical. Your job? Make it better without breaking it. Here’s how you can approach it: 1. Understand before you refactor. Don’t just dive in and start deleting things. Read it. Map it out. Use tools to speed this up. Ex - Bito can summarize logic or explain what a function or entire files does in plain English. Saves hours. 2. Write tests first. If there are no tests, you’re flying blind. Write some coverage before you change anything, so you know if it breaks. 3. Fix small, high-leverage things. → Rename variables (’temp3’ → ’averageTemp’). → Split up massive functions. → Add comments where the logic is dense. Small changes compound over time. 4. Leave it better than you found it. If you struggled to figure something out, document it. Add a test. Refactor the worst parts. Legacy code is how we got here… it’s alive, it’s evolving. Don’t hate it. Maintain it. And when you’ve got the right tools, the process doesn’t have to be painful. I’ve seen teams clean up years of spaghetti with AI tools that: → Identify unclear code. → Suggest refactors. → Catch bugs early. The goal isn’t to “modernize” everything. It’s to make legacy code easier to extend, understand, and trust. Fix what matters. Move fast. Don’t break things. #bug #code #ai #developer