{
  "slug": "Successfully-Migrating-from-a-Monolith-to-Microservices-with-a-Technical-Debt-Approach-aa08d713deec",
  "title": "Successfully Migrating from a Monolith to Microservices with a Technical-Debt Approach",
  "subtitle": "Deciding to migrate from a large, aging monolithic system to a microservices architecture is often a reactive response to…",
  "excerpt": "Deciding to migrate from a large, aging monolithic system to a microservices architecture is often a reactive response to…",
  "date": "2025-12-23",
  "tags": [
    "Microservices",
    "Architecture"
  ],
  "readingTime": "4 min",
  "url": "https://medium.com/@mobinshaterian/successfully-migrating-from-a-monolith-to-microservices-with-a-technical-debt-approach-aa08d713deec",
  "hero": "https://cdn-images-1.medium.com/max/800/1*4S3ibU4BKvWedf8IY_wTtA.png",
  "content": [
    {
      "type": "paragraph",
      "html": "<strong>Introduction</strong><br>&nbsp;Deciding to migrate from a large, aging monolithic system to a microservices architecture is often a reactive response to inefficiencies and unmanageable complexity in the current code base. This process is not merely a technical rewrite; it demands a deep reconsideration of development culture, business processes, and team structure. This article analyses the challenges present in inherited monolithic systems, identifies the root causes of problems, and proposes a step-by-step roadmap for a successful migration."
    },
    {
      "type": "image",
      "src": "https://cdn-images-1.medium.com/max/800/1*4S3ibU4BKvWedf8IY_wTtA.png",
      "alt": "Successfully Migrating from a Monolith to Microservices with a Technical-Debt Approach",
      "caption": "",
      "width": 1024,
      "height": 1024
    },
    {
      "type": "heading",
      "level": 2,
      "text": "1. Diagnosing Root Problems: Why Did Inefficient Code Get Inherited?"
    },
    {
      "type": "paragraph",
      "html": "The first and most important step is to answer why the existing system has reached its current state. Without understanding these root causes, a new microservices architecture is likely to repeat the same mistakes and fail. Common reasons include:"
    },
    {
      "type": "list",
      "ordered": false,
      "items": [
        "<strong>Business delivery pressure</strong>: The business’s need for rapid product delivery in a competitive market puts development teams under pressure, often leading to shortcuts in code quality and testing.",
        "<strong>Weak large-scale design capability</strong>: Developers may lack sufficient training or experience in designing large, maintainable systems at the monolith scale.",
        "<strong>Lack of a culture of code review and standardization</strong>: Without team mechanisms for continuous quality control, “dirty” code accumulates.",
        "<strong>Technical debt influx</strong>: As per research, technical debt is often caused by the pressure to ship fast, postponed cleanup, inadequate process practices, and skipping refactoring."
      ]
    },
    {
      "type": "paragraph",
      "html": "Recognizing these root issues helps ground the migration process: you are not just rewriting code, you are repairing culture, process, architecture, and team behaviors."
    },
    {
      "type": "heading",
      "level": 2,
      "text": "2. First Practical Step: Clarify the Current State via Continuous Quality Control"
    },
    {
      "type": "paragraph",
      "html": "To begin any corrective process, the current state must be made visible to all stakeholders (developers and product managers alike)."
    },
    {
      "type": "list",
      "ordered": false,
      "items": [
        "<strong>Use static-analysis tools</strong>:<br>&nbsp;Since team-wide code review on a large and complex monolith is inefficient, using tools such as SonarQube is essential. These automatically measure code quality, bugs, vulnerabilities, and accumulated technical debt.",
        "<strong>Training and public visibility of quality metrics</strong>:<br>&nbsp;Developers should see their code quality on a daily basis. Product managers should understand what technical debt means, how it impacts future delivery speed, and should be prevented from growing unchecked.",
        "<strong>Make metrics part of the process</strong>:<br>&nbsp;According to modern studies, organizations that audit architecture, code, documentation, and dependencies before modernization see significantly better outcomes."
      ]
    },
    {
      "type": "paragraph",
      "html": "By making the state visible, you build a shared language around quality, debt, and improvement."
    },
    {
      "type": "heading",
      "level": 2,
      "text": "3. Architecting Analysis: Identifying Domain Boundaries and Entanglements"
    },
    {
      "type": "paragraph",
      "html": "The next step in the migration process is to deeply understand the business domain via Domain-Driven Design (DDD). Defining domain boundaries logically is vital to splitting services in a microservices architecture."
    },
    {
      "type": "list",
      "ordered": false,
      "items": [
        "<strong>Issue A: Improper integration of CRUD and ETL logic</strong><br>&nbsp;For instance, the monolith may mix pure CRUD (read/write to database) operations with heavy ETL (Extract, Transform, Load) processes. This can lead to:",
        "Repeated synchronizations: each monolith attempts its own database extraction/sync.",
        "Violation of the Single Responsibility Principle: one module handles both operational logic and analytic/ETL logic, harming scalability.",
        "<strong>Issue B: Duplication of extraction processes</strong><br>&nbsp;Another reported problem: the monolith repeats data‐extraction processes from various sources (databases, Excel files, server logs) in multiple parts of the system. Rather than having one specialized service for this, several chunks of the monolith replicate work, causing maintenance headaches, computational waste, and chaotic ownership."
      ]
    },
    {
      "type": "paragraph",
      "html": "As research on microservices migration shows, when domain boundaries are weak or service boundaries are poorly defined, technical debt can rise rapidly."
    },
    {
      "type": "paragraph",
      "html": "Thus, invest time upfront in domain modeling, understanding the business processes, data flows, and dependencies between modules."
    },
    {
      "type": "heading",
      "level": 2,
      "text": "4. Cultural Challenges: Testing, Documentation, and ETL Performance"
    },
    {
      "type": "paragraph",
      "html": "The cultural barriers in the migration process are as important as the technical ones."
    },
    {
      "type": "list",
      "ordered": false,
      "items": [
        "<strong>Lack of culture for testing and documentation</strong>:<br>&nbsp;In many organizations, especially those under delivery pressure, there is insufficient time allocated to test coverage and documentation. There is an expectation that applications “just work” without full scenario testing or detailed docs.",
        "<strong>Impact on ETL processes</strong>:<br>&nbsp;This is particularly destructive when designing ETL processes (which typically scale with data volume). A service that works fine at a small scale becomes extremely slow when data volume grows, increasing database response times exponentially. This is directly due to a lack of performance testing and not proactively designing for growth.",
        "<strong>Technical debt in the migration context</strong>:<br>&nbsp;Research indicates technical debt evolves differently in microservice systems: if you don’t build observability, automation, and governance at the start, you pay a higher “interest” cost."
      ]
    },
    {
      "type": "paragraph",
      "html": "Therefore, a successful migration ought to emphasize culture change: clear standards for tests, docs, performance, and observability must be established early."
    },
    {
      "type": "heading",
      "level": 2,
      "text": "5. Migration Strategy: Creating “Macro” Versions & Standardization"
    },
    {
      "type": "paragraph",
      "html": "The final phase is defining and implementing the new architecture. The strategy focuses on the separation of responsibilities and creating new standards."
    },
    {
      "type": "list",
      "ordered": false,
      "items": [
        "<strong>Final step: Split into “macro” services</strong><br>&nbsp;Define macro-services (larger than small service slices but smaller than the monolith) for key responsibilities:",
        "<strong>CRUD Macro-service</strong>: Handles core transactional logic — business domain read/write operations.",
        "<strong>ETL/Data Sourcing Macro-service</strong>: Handles all data extraction and transformation from external sources (other databases, files, logs, etc.).",
        "<strong>New Standardization and Guardrails</strong><br>&nbsp;To ensure the new microservices don’t become future monoliths, define a comprehensive standard for development:",
        "<strong>Design Principles</strong>: New services should follow SOLID principles and Clean Code structure.",
        "<strong>Observability</strong>:Logging: All service logs should be centrally collected (e.g., via ELK Stack).<br>Distributed Tracing: Implement OpenTelemetry to trace request flows across services for debugging and troubleshooting.<br>&nbsp;By establishing these, you can expect the new services to be created with a <strong>consistent style</strong>, so that team members can switch between them comfortably."
      ]
    },
    {
      "type": "paragraph",
      "html": "<strong>Conclusion</strong><br>&nbsp;Migrating from a monolith to microservices is a golden opportunity to reform development culture. By starting with assessing current code quality (via SonarQube or similar), precisely understanding domain boundaries, then separating entangled logic (CRUD vs ETL), and committing to testing, documentation, and observability tools (ELK, OpenTelemetry), you can build a foundation for a future architecture that is scalable, maintainable, and free of legacy technical-debt burdens."
    }
  ]
}