FastBuild: Accelerating Docker Image Building for Efficient Development and Deployment of Container

Abstract

Docker containers have been increasingly adopted on various computing platforms to provide a lightweight virtualized execution environment. Compared to virtual machines, this technology can often reduce the launch time from a few minutes to less than 10 seconds, assuming the Docker image has been locally available. However, Docker images are highly customizable, and are mostly built at runtime from a remote base image by running instructions in a script (the Dockerfile). During the instruction execution, a large number of input files may have to be retrieved via the Internet. The image building may be an iterative process as one may need to repeatedly modify the Dockerfile until a desired image composition is received. In the process, every input file required by an instruction has to be remotely retrieved, even if it has been recently downloaded. This can make the process of building of an image and launching of a container unexpectedly slow. To address the issue, we propose a technique, named FastBuild, that maintains a local file cache to minimize the expensive file downloading. By non-intrusively intercepting remote file requests, and supplying files locally, FastBuild enables file caching in a manner transparent to image building. To further accelerate the image building, FastBuild overlaps operations of instructions' execution and writing intermediate image layers to the disk. We have implemented FastBuild. And experiments with images and Dockerfiles obtained from Docker Hub show that the system can improve building speed by up to 10 times, and reduce downloaded data by 72%.