A few weeks back, we launched a buildkit-based remote builder that uses a registry-mirror service to speed up interactions with registry.fly.io images. This lets you opt-in to faster builds and deploys by using a new remote builder through the newly-added --buildkit flag in fly deploy.
This week, we’ll be rolling out changes to bring these registry-mirror optimizations to all existing remote builders (including Depot), without any changes needed. This will bring faster and more reliable image builds and deploys to all existing remote builders.
To make this work, we added some logic to the Fly app serving the registry.fly.io registry that will automatically replay requests to the local registry-server mirror on the same host as your remote builder machine, using the same fly-replay feature available to any other Fly app. In order for our deploy orchestrator to locate the registry mirror that contains your image before it’s available upstream, recent versions of flyctl include the remote builder ID as build metadata (and more recently, also for Depot-based builds). You’ll need flyctl version v0.3.180 or later for the faster remote builder-based deploys to work properly (on older versions, the deploy logic will just wait until the image is fully uploaded upstream as a fallback).
So be sure to update flyctl and enjoy faster deploys! Please let us know if you experience any registry-related issues as these changes are rolled out over the next few days.