Guides
How to run concurrent Docker builds safely
Parallel matrix legs contend and builds slow down or fail.
5 min read
Parallel matrix legs contend and builds slow down or fail.
Why it happens
Several builds share one builder without enough CPU, or write to the same cache scope simultaneously.
How to fix it
- Scale the builder to the concurrency you need, or use one builder per architecture
- Scope cache per image rather than sharing one scope across unrelated builds
- Use docker buildx bake to build several targets in one coordinated session
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