Improving Deployment Speed with Lazy Image Streaming

Replit Deployments provides a service that converts users' code into container images and quickly deploys them to Google Cloud VM or Cloud Run.

However, when using large container images, the process of pulling and decompressing the image takes several minutes. This is a bottleneck caused by network bandwidth limitations and the CPU-intensive decompression process.

Reducing image size would be the ideal solution, but it's difficult to force all users to optimize their Dockerfiles. Instead of reducing image size, Replit adopted an approach that speeds up image pulling and boot time through Lazy Image Streaming.

Lazy Image Streaming is a technology that, instead of immediately downloading all files in an image when a container runs, streams only the files needed at the moment they're needed, dramatically reducing deployment time.