Docker Images - Size matters, But So Does Performance
Introduction I recently went through the exercise of re-building a Docker image based on what was supposed to be a stable, well-known application codebase. Along the way I observed an unexpected performance issue. The application contained within the Docker image was just a Java command line utility for parsing some yaml files to provision kafka resources on our hosted development clusters. The code had not been changed for several months, so this was supposed to just be a matter of setting up a local copy of the Docker image instead of pulling down a trusted third party's image from Dockerhub. The application was bundled within a Docker contrainer whose Dockerfile was alongside the code, so it should have been a simple matter of using that to produce the image and pushing it to our own repo, and then pulling that down for our runtime use. It's the same, so why's it different? We had been running with the existing third party Docker image for several months, so there was a ...