Building Managarm

This guide shows how to build a managarm distribution from source utilising the bootstrap-managarm patches and build scripts.

Building a managarm distribution from source

Build environment

To make sure that all build environments work properly, it is recommended to setup a build environment with our lightweight containerized build runtime cbuildrt (see below for instructions). It is also possible to build with Docker (see here), or by installing the dependencies manually (see here), but these methods are no longer recommended.

Make sure that you have at least 20 - 30 GiB of free disk space.


  1. Create a directory which will be used for storing the source and build directories. Here we use ~/managarm, but it can be any directory.
    mkdir ~/managarm && cd ~/managarm
  2. Install the xbstrap build system via pip3:
    pip3 install xbstrap
  3. The git, subversion and mercurial tools are required on the host (whether you build in a container or not). Install these via your package manager.
  4. Clone this repository into a src directory and create a build directory:
    git clone src
    mkdir build

Creating a cbuildrt environment

  1. Download and install the latest cbuildrt release by running:

    xbstrap prereqs cbuildrt xbps

    Note: If you choose to build cbuildrt from source, make sure to place the resulting binary either in $PATH or in ~/.xbstrap/bin.

  2. Download and unpack the latest Managarm rootfs somewhere:

    curl -o managarm-rootfs.tar.gz
    tar xvf managarm-rootfs.tar.gz
  3. Inside the build directory, create a file named bootstrap-site.yml with the following contents:

      format: xbps
      runtime: cbuildrt
      rootfs:  /path/to/your/rootfs
      uid: 1000
      gid: 1000
      src_mount: /var/lib/managarm-buildenv/src
      build_mount: /var/lib/managarm-buildenv/build
      allow_containerless: true

    Note: you must keep the src_mount and build_mount values as shown above if you want to be able to use pre-built tools from our build server. These paths refer to locations on the container, not on your host machine. Also note that these paths cannot be changed after starting the build; doing so will likely result in a broken directory tree.

  4. In the build/bootstrap-site.yml file you just created, replace the container.rootfs key with the path to your rootfs.


  1. Initialize the build directory with

    cd build
    xbstrap init ../src
  2. Decide which software you want to include in the image you create. There are several meta-packages available which help you decide this:

    • base: just enough to boot into kmscon plus some functional commands to play with (such as less and grep)
    • base-devel: same as base plus some extra development tools (such as gcc and binutils)
    • weston-desktop: full managarm experience with a selection of terminal and GUI software
  3. To actually execute the build, we recommend that you install the necessary tools and packages as binaries from our build server. This can save you multiple hours of compilation, depending on your machine.

    Note: this only works if you build in a container (though this is untested with Docker). Containerless builds must do a full build from source (see below).

    xbstrap pull-pack --deps-of <meta-package> mlibc mlibc-headers # e.g xbstrap pull-pack --deps-of base mlibc mlibc-headers
    xbstrap install --deps-of <meta-package>
    # The following two commands fetch managarm and mlibc (plus their required tools) to enable local development:
    xbstrap download-tool-archive --build-deps-of managarm-system --build-deps-of managarm-kernel --build-deps-of mlibc
    xbstrap install --rebuild managarm-system managarm-kernel mlibc mlibc-headers

    If instead you want to build everything from source, simply run xbstrap install <group>, e.g xbstrap install weston-desktop. Note that this can take multiple hours, depending on your machine.

Creating Images

After managarm's packages have been built, building a HDD image of the system is straightforward.

For all methods, the image creation and updation commands shown below require the following programs to be installed on the host: rsync, losetup, sfdisk, mkfs.ext2, mkfs.vfat. Refer to image_create for more details on this.

  1. Decide what method you want to use to copy files to the image:

    1. Using libguestfs (the default method). We recommend this when root access is not possible or desirable. However, it is much slower than method 2 and requires some setup on the host (see below).
    2. Using a classic loopback and mount (requires root privileges). We recommend this when root access is acceptable because it is the fastest method and most guaranteed to work.
    3. Via Docker container (only works with the Docker build method). This is handy in case the user is in the docker group since it does not require additional root authentication. We discourage this because it uses docker run --privileged (which is not safer than giving root access) and currently has some bugs.

    Going with method 1 will require libguestfs to be installed on the host. After installing libguestfs, if you encounter errors while making the image it might be necessary to run the following:

    sudo install -d /usr/lib/guestfs
    sudo update-libguestfs-appliance
  2. Add the following to build/bootstrap-site.yml, depending on what mount method you have chosen:

      mount-using: 'loopback' # or guestfs/docker
  3. Create the image:

    xbstrap run initialize-empty-image
  4. Copy the system onto it:

    xbstrap run make-image
  5. Launch the image using QEMU:

    xbstrap run qemu # Note that you can combine the last two operations: xbstrap run make-image qemu

Alternatively, you can call the necessary scripts manually (check their help messages for more information):

  • ../src/managarm/tools/ and ../src/scripts/ for copying the files onto the image (the mount method can be selected with the --mount-using argument)
  • ../src/scripts/ qemu for launching QEMU