Gaining Docker Image Size Efficiencies By Separating Application Layers

Luke Patterson Docker, Java, Problem Solving, Spring Boot, Technology Snapshot Leave a Comment

Problem

I was pushing a new Docker image tag for each application code commit, and the admins of the private registry were getting annoyed at how much space I was using.

Solution Summary

Yes, I know there are strategies to clean up old tags but I first wanted to reduce the impact of the tags I was pushing. With the right layering strategy, I knew I could reduce the net registry size increase of consecutive tag pushes.

I wanted to only push what had actually changed in the application. In addition to reducing the impact on the registry, having smaller tag deltas could possibly speed up rolling deployments since nodes could potentially have less to download.