Reusing Bazel's Analysis Cache by Cloning Micro-VMs

This conference talk explores how to optimize Bazel-integrated CI workflows through Firecracker micro-VMs and snapshotting techniques. Learn how to overcome bottlenecks in Bazel's analysis phase by implementing a system that serializes and saves running microVMs, allowing for reuse of warm Bazel processes and analysis caches in subsequent builds. Discover how this approach reduced median CI run duration by nearly 8x, with most runs completing in just seconds. The presentation also covers advanced techniques for remote snapshot sharing across machines using userfaultfd and network block devices to capture disk and memory operations, maintaining performance benefits even through machine restarts and failures. Speaker Maggie Lou walks through these optimizations and demonstrates their significant performance improvements in this 28-minute Linux Foundation talk.