Building Docker images 7x Faster with Clipper
Clipper introduces BuildKit profiling, a tool that analyzes Docker image builds to identify bottlenecks and optimize caching. Users can achieve up to 7x faster build times by visualizing build phases, layer sizes, and cache misses to restructure Dockerfiles. The profiler integrates with Docker's BuildKit to provide granular performance data without modifying existing workflows.
Background
- **Docker images** are lightweight, standalone packages that contain everything needed to run a piece of software (code, runtime, libraries). Building them efficiently matters because large or frequently updated images slow down development and deployment pipelines.
- **BuildKit** is the modern, open-source backend Docker uses to build images. It replaced the older "legacy builder" and supports features like parallel builds, caching, and multi-stage builds — but still has performance bottlenecks in certain real-world scenarios.
- **Clipper** (clipper.dev) is a startup building a high-performance, drop-in replacement for Docker's build system, claiming dramatic speedups (here, 7x). This article walks through a case study where they achieved that speedup by profiling a slow BuildKit build, identifying CPU and I/O bottlenecks, and optimizing the caching strategy — all using Clipper's own profiling tools.