1.2.4 Oracle Container Runtime for Docker 17.06

This release disables communication with legacy registries, running the v1 protocol, by default. While it is possible to allow communication using this version of the protocol by setting the --disable-legacy-registry=false daemon option, you should be aware that support for this is deprecated.

The --graph daemon option is also deprecated in favor of the --data-root option, as this is more descriptive and less confusing. The option indicates the path of the parent directory that contains data for images, volumes, containers, networks, swarm cluster state and swarm node certificates.

One of the most significant changes in this release is the addition of support for multi-stage builds. This allows users to create Dockerfiles that pull intermediate build images that may be used to compile the final image, but which do not need to be included in the final image, itself. This can help to reduce image sizes and improve load times and performance of running containers. More information on multi-stage builds can be found in Section 5.5, “Creating Multi-stage Docker Image Builds”.

Other changes to the build environment include the ability to use build-time arguments in the form of ARG instructions in a Dockerfile, which allows you to pass environment variables into each image. FROM instructions support variables defined in ARG instructions that precede them in the Dockerfile.

Changes and improvements for Docker logging and networking are largely focused on improving Docker Swarm functionality. Numerous Docker Swarm changes and improvements have gone into this release. Customers are reminded that Docker Swarm remains in technical preview in this release.

In this release, the overlay2 storage driver is supported in conjunction with SELinux. In previous releases, the Docker Engine did not start when SELinux was enabled and an overlay file system was in use. This check has been dropped as newer kernels have support for this combination and the packages for SELinux support have been updated.

Also included in this release is the docker-storage-config utility, that can be used to help new users correctly set up Docker storage for a new installation, so that the configuration follows Oracle guidelines. See Section 2.7.1, “Configuring Docker Storage Automatically” for more information.