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diff --git a/images/README.md b/images/README.md new file mode 100644 index 000000000..9880946a6 --- /dev/null +++ b/images/README.md @@ -0,0 +1,70 @@ +# Container Images + +This directory contains all images used by tests. + +Note that all these images must be pushed to the testing project hosted on +[Google Container Registry][gcr]. This will happen automatically as part of +continuous integration. This will speed up loading as images will not need to be +built from scratch for each test run. + +Image tooling is accessible via `make`, specifically via `images/Makefile`. + +## Why make? + +Make is used because it can bootstrap the `default` image, which contains +`bazel` and all other parts of the toolchain. + +## Listing images + +To list all images, use `make list-all-images` from the top-level directory. + +## Loading and referencing images + +To build a specific image, use `make load-<image>` from the top-level directory. +This will ensure that an image `gvisor.dev/images/<image>:latest` is available. + +Images should always be referred to via the `gvisor.dev/images` canonical path. +This tag exists only locally, but serves to decouple tests from the underlying +image infrastructure. + +The continuous integration system can either take fine-grained dependencies on +single images via individual `load` targets, or pull all images via a single +`load-all-images` invocation. + +## Adding new images + +To add a new image, create a new directory under `images` containing a +Dockerfile and any other files that the image requires. You may choose to add to +an existing subdirectory if applicable, or create a new one. + +All images will be tagged and memoized using a hash of the directory contents. +As a result, every image should be made completely reproducible if possible. +This means using fixed tags and fixed versions whenever feasible. + +Notes that images should also be made architecture-independent if possible. The +build scripts will handling loading the appropriate architecture onto the +machine and tagging it with the single canonical tag. + +Add a `load-<image>` dependency in the Makefile if the image is required for a +particular set of tests. This target will pull the tag from the image repository +if available. + +## Building and pushing images + +All images can be built manually by running `build-<image>` and pushed using +`push-<image>`. Note that you can also use `build-all-images` and +`push-all-images`. Note that pushing will require appropriate permissions in the +project. + +The continuous integration system can either take fine-grained dependencies on +individual `push` targets, or ensure all images are up-to-date with a single +`push-all-images` invocation. + +## Multi-Arch images + +By default, the image is built for host architecture. Cross-building can be +achieved by specifying `ARCH` variable to make. For example: + +``` +$ make ARCH=aarch64 rebuild-default +``` |