94.88% CI/CD Infrastructure Cost Reduction

Phase 1: The Initial Crisis (June 2024)

Problem: Unity Editor provides no CPU usage control during builds. When 2+ projects build simultaneously, the CI/CD server crashes.

Root Cause Analysis:

• Git clone → Unity Editor project open: 8-9 minutes (initial compile)
• Unit testing: ~1 minute
• Build optimization phase: 2-3+ minutes
• All phases consume 100% available CPU

Solution: Trade-off approach — maintain project files & artifacts (skip “from scratch” builds), set optimization level to 0 (skip optimization phase).

Result: Reduced initial compile time from 10 min → 1 min, prevented server crashes.

Phase 2: Containerization + Build Optimization (May 2025)

Goal: Eliminate the trade-off from Phase 1 — enable clean builds without sacrificing speed.

Solution 1: Docker containerization with CPU allocation — enabled concurrent builds without crashes.

Solution 2: PID-level profiling + Unity settings optimization — analyzed CPU usage at 5-second intervals, tuned emscriptenArgs, Il2CppCodeGeneration, managedStrippingLevel, etc.

Limitation: Still running on the same CI/CD server.

Phase 3: Cloud-Native Architecture (June 2025)

Proactive Initiative: Docker containerization in Phase 2 proved builds could run in isolated environments. This raised a question: if containers can run independently, why not leverage cloud infrastructure for parallel, on-demand execution?

Solution: Azure Batch + Spot VMs — completely separated Unity build/test environment from CI/CD server. On-demand ephemeral containers, pay only for actual compute time.

Analysis Period: May 5 - June 29, 2025 (56 days, 37 active days) | Projects: 2 Unity VR projects (855 CI jobs, 166 CD jobs)