37signals Dev — Running our Docker registry on-prem with Harbor

As of early 2025, we’re deploying all of our applications with Kamal using Docker as our containerization platform. The container registry that holds our app images is one of the most integral pieces of our deployment pipeline. Like many organizations, we’d been using external container registries for years. Our ecosystem was tightly coupled to both Dockerhub and Amazon’s Elastic Container Registry. However, as part of our cloud exit and kamalization journey, several issues started emerging:.