If you are looking to make Docker available on your favorite software distribution, this document is for you. It summarizes the requirements for building and running the Docker client and the Docker daemon.
If possible, your package should be called “docker”. If that name is already taken, a second choice is “docker-engine”. Another possible choice is “docker.io”.
The Docker project maintains its own build and release toolchain. It is pretty neat and entirely based on Docker (surprise!). This toolchain is the canonical way to build Docker. We encourage you to give it a try, and if the circumstances allow you to use it, we recommend that you do.
You might not be able to use the official build toolchain - usually because your distribution has a toolchain and packaging policy of its own. We get it! Your house, your rules. The rest of this document should give you the information you need to package Docker your way, without denaturing it in the process.
The Dockerfile contains the most up-to-date list of build-time dependencies.
All Go dependencies are vendored under “./vendor”. They are used by the official build, so the source of truth for the current version of each dependency is whatever is in “./vendor”.
If you would rather (or must, due to distro policy) package these dependencies yourself, take a look at “vendor.mod” for an easy-to-parse list of the exact version for each.
Please, please, please do not strip any compiled binaries. This is really important.
In our own testing, stripping the resulting binaries sometimes results in a binary that appears to work, but more often causes random panics, segfaults, and other issues. Even if the binary appears to work, please don't strip.
See the following quotes from Dave Cheney, which explain this position better from the upstream Golang perspective.
Super super important: Do not strip go binaries or archives. It isn‘t tested, often breaks, and doesn’t work.
To quote myself: “Please do not strip Go binaries, it is not supported, not tested, is often broken, and doesn't do what you want”
To unpack that a bit
- not supported, as in, we don't support it, and recommend against it when asked
- not tested, we don't test stripped binaries as part of the build CI process
- is often broken, stripping a go binary will produce anywhere from no, to subtle, to outright execution failure, see above
To clarify my previous statements.
- I do not disagree with the debian policy, it is there for a good reason
- Having said that, it stripping Go binaries doesn't work, and nobody is looking at making it work, so there is that.
Thanks for patching the build formula.
Please use our build script (“./hack/make.sh”) for compilation.
DOCKER_BUILDTAGSThere are build tags for disabling graphdrivers, if necessary. By default, support for all graphdrivers are built in.
To disable btrfs:
export DOCKER_BUILDTAGS='exclude_graphdriver_btrfs'
To disable devicemapper:
export DOCKER_BUILDTAGS='exclude_graphdriver_devicemapper'
NOTE: if you need to set more than one build tag, space separate them:
export DOCKER_BUILDTAGS='exclude_graphdriver_devicemapper exclude_graphdriver_btrfs'
To function properly, the Docker daemon needs the following software to be installed and available at runtime:
Additionally, the Docker client needs the following software to be installed and available at runtime:
The Docker daemon has very specific kernel requirements. Most pre-packaged kernels already include the necessary options enabled. If you are building your own kernel, you should check out contrib/check-config.sh.
Note that in client mode, there are no specific kernel requirements, and that the client will even run on alternative platforms such as Mac OS X / Darwin.
Some of Docker's features are activated by using optional command-line flags or by having support for them in the kernel or userspace. A few examples include:
linux/btrfs.h and linux/btrfs_tree.h, present in 4.12+; and BTRFS support enabled in the kernel)Docker expects to run as a daemon at machine startup. Your package will need to include a script for your distro's process supervisor of choice. Be sure to check out the “contrib/init” folder in case a suitable init script already exists.
In general, Docker should be run as root, similar to the following:
dockerd
Generally, it is encouraged that additional configuration be placed in /etc/docker/daemon.json.