Multi-stage builds allow you to drastically reduce the To exclude files not relevant to the build (without restructuring your source
Installed on the host where you run the docker build command. Those files as build context to the daemon. Performs a git clone of the repository on the local machine, and sends When building an image using a remote Git repository as build context, Docker The examples in this section use here documentsįor convenience, but any method to provide the Dockerfile on stdin can beįor example, the following commands are equivalent:ĭocker build -t myimage:latest -f- << EOF Or in situations where the Dockerfile is generated, and should not persist Piping a Dockerfile through stdinĬan be useful to perform one-off builds without writing a Dockerfile to disk, To see how big your build context is, look for a message like this whenīuilding your Dockerfile: Sending build context to Docker daemon 187.8MBĭocker has the ability to build images by piping Dockerfile through stdin Time to build the image, time to pull and push it, and the container runtime Results in a larger build context and larger image size. Inadvertently including files that are not necessary for building an image $ docker build -no-cache -t helloapp:v2 -f dockerfiles/Dockerfile context $ mv Dockerfile dockerfiles & mv hello context The image from within the build context (. Write “hello” intoĪ text file named hello and create a Dockerfile that runs cat on it.
Of where the Dockerfile actually lives, all recursive contents of files andĭirectories in the current directory are sent to the Docker daemon as the buildĬreate a directory for the build context and cd into it. By default, the Dockerfile is assumed to be located here,īut you can specify a different location with the file flag ( -f). When you issue a docker build command, the current working directory is called Methodology to get a feel for the motivations of running containers in such a Refer to Processes under The Twelve-factor App
By “ephemeral”, we mean that the container can be stoppedĪnd destroyed, then rebuilt and replaced with an absolute minimum set up and The image defined by your Dockerfile should generate containers that are asĮphemeral as possible. General guidelines and recommendations Create ephemeral containers The running container, such as writing new files, modifying existing files, andĭeleting files, are written to this writable container layer.įor more on image layers (and how Docker builds and stores images), seeĪbout storage drivers. (the “container layer”) on top of the underlying layers. When you run an image and generate a container, you add a new writable layer