Moby

Moby, a toolkit for building custom minimal, immutable Linux distributions.

• Good, secure defaults included
• Everything is replaceable and customisable
• Immutable infrastructure applied to building Linux distributions
• Completely stateless, but persistent storage can be attached
• Easy tooling, with easy iteration
• Built with containers, for running containers
• Designed for building and running clustered applications, including but not limited to container orchestration such as Docker or Kubernetes
• Designed from the experience of building Docker Editions, but redesigned as a general purpose toolkit
• Designed to be managed by external tooling, such as Infrakit or similar tools
• Includes a set of longer term collaborative projects in various stages of development to innovate on kernel and userspace changes, particularly around security

Getting Started

Build

Simple build instructions: use make to build. This will build the Moby customisation tool and a Moby initrd image.

If you already have a Go build environment and installed the source in your GOPATH you can do go install github.com/docker/moby/cmd/moby to install the moby tool instead, and then use moby build moby.yaml to build the example configuration.

Build requirements

• GNU make
• GNU or BSD tar (not busybox tar)
• Docker

Booting and Testing

If you have a recent version of Docker for Mac installed you can use moby run <name> to execute the image you created with moby build <name>.yaml

The Makefile also specifies a number of targets:

• make qemu will boot up a sample Moby in qemu in a container
• on OSX: make hyperkit will boot up Moby in hyperkit
• make test or make hyperkit-test will run the test suite
• There are also docs for booting on Google Cloud
• More detailed docs will be available shortly, for running single hosts and clusters.

Customise

To customise, copy or modify the moby.yaml to your own file.yaml or use on of the examples and then run ./bin/moby build file.yaml to generate its specified output. You can run the output with ./scripts/qemu.sh or ./scripts/hyperkit.sh, or on other platforms.

Yaml Specification

The Yaml format is loosely based on Docker Compose:

• kernel specifies a kernel Docker image, containing a kernel and a filesystem tarball, eg containing modules. mobylinux/kernel is built from kernel/
• init is the base init process Docker image, which is unpacked as the base system, containing init, containerd, runc and a few tools. Built from base/init/
• system are the system containers, executed sequentially in order. They should terminate quickly when done.
• daemon is the system daemons, which normally run for the whole time
• files are additional files to add to the image
• outputs are descriptions of what to build, such as ISOs.

For the images, you can specify the configuration much like Compose, with some changes, eg capabilities must be specified in full, rather than add and drop, and there are no volumes only binds.

The config is liable to be changed, and there are missing features; full documentation will be available shortly.