How We Reduced Dependabot Noise in Our Monorepo

## Why we needed Dependabot Our dependency management had become increasingly manual and error-prone. - InnerSource Terraform modules were frequently updated, but consuming projects had to manually track and apply those changes. Over time, projects fell behind, making upgrades harder and increasing the risk of incompatibilities. - Spring Boot dependencies were rarely updated once initially set. This led to known vulnerabilities remaining in the codebase, triggering repeated alerts from Nexus SCA. As a result, CI pipelines began failing due to vulnerability policy violations—often for issues that already had fixes available. We needed an automated way to keep both infrastructure and application dependencies up to date to avoid security alerts, CI failures, and the growing cost of manual updates, which led us to adopt [Dependabot](https://github.com/dependabot) from GitHub. Following measures we took to manage dependabot: ### Grouped Updates and Smart Scheduling To keep dependency updates manageable in our monorepo, we optimized both how and when Dependabot creates pull requests. We **grouped subcomponents by package ecosystem** to reduce PR noise: - All Maven-based updates generate a single pull request - All Docker-based updates generate a separate single pull request - The same pattern applies to other ecosystems We also tuned the update frequency based on impact and change rate: - Terraform dependencies are checked daily, since our InnerSource modules evolve frequently - All other ecosystems (Maven, Docker, etc.) are checked weekly to balance freshness with review effort This combination of grouped pull requests and ecosystem-specific schedules keeps dependencies up to date while avoiding an overwhelming number of PRs—making automation practical and sustainable at scale. ```yaml updates: -package-ecosystem: "maven" directories: - "/packages/app_a" - "/packages/app_b" schedule: interval: "weekly" day: "tuesday" time: "19:00" ``` ### Treating Dependabot PRs Like Any Other Feature To ensure quality and confidence, we treat Dependabot pull requests exactly like regular feature branches—not as “special” or auto-approved changes. - Every Dependabot PR triggers the same CI pipelines as a developer-created branch - **Automated test suites** run for each pull request, validating both infrastructure and application changes - Updates are only merged after passing all required checks and reviews By applying the same standards to automated dependency updates, we ensure that keeping dependencies current does not compromise stability or reliability. This approach allows us to safely automate updates while maintaining the same level of trust and rigor as any other code change. ### Active Monitoring with Clear Ownership To avoid stalled or ignored dependency updates, we actively monitor Dependabot pull requests by assigning clear ownership. - Each Dependabot PR is linked to a small Jira task and explicitly assigned to a developer - The assigned developer reviews the PR outcome and investigates any CI or test failures - If a PR fails, they identify the cause (breaking change, test issue, config update needed) and take the necessary corrective action This lightweight process ensures Dependabot PRs don’t become background noise. By combining automation with **human ownership**, we keep dependency updates moving forward and prevent failures or vulnerabilities from lingering unnoticed. ### Running Dependabot CI During Non-Working Hours To minimize impact on day-to-day development, we schedule **CI runs for Dependabot pull requests during non-working hours**. - Dependabot-triggered pipelines are prioritized to run outside peak development time - This reduces contention on shared CI resources while other developers are actively working - Teams still get fresh results by the next working day, without slowing down feature development By shifting automated dependency validation to off-hours, we balance **cost, performance, and developer productivity**—keeping CI efficient without adding friction to daily workflows. ## Benefits Achieved By combining automated updates, smart grouping, clear ownership, and off-hours CI execution, we’ve seen tangible benefits: - Significant reduction in dependency-related CI failures - Lower vulnerability alerts from Nexus SCA due to timely updates - Fewer, more meaningful pull requests, making reviews faster and easier - Improved stability across Terraform modules and Spring Boot applications - Better use of CI resources without impacting active development Overall, this approach has turned dependency management from a reactive problem into a **predictable, low-noise, and reliable process**.