github.com/opencontainers/runtime-tools@v0.9.0/contrib/rootfs-builder/README.md (about)

     1  # Building `rootfs-*.tar.gz`
     2  
     3  The root filesystem tarball is based on [Gentoo][]'s stage3s (e.g. the
     4  [amd64 stage3][stage3-amd64]).  We check for a valid [GnuPG
     5  signature][gentoo-signatures]), copying a [minimal
     6  subset](rootfs-files) to the root filesytem, and adding symlinks for
     7  all BusyBox commands.  To rebuild the tarball based on a newer stage3,
     8  run:
     9  
    10  ```
    11  $ touch get-stage3.sh
    12  $ make rootfs-amd64.tar.gz
    13  ```
    14  
    15  ## Platform tarballs
    16  
    17  The extraction requires a local machine capable of executing the
    18  extracted BusyBox.  Extraction assumes amd64, but if your local
    19  machine is a different platform, set `ARCHES`.  For example:
    20  
    21  ```
    22  $ make ARCHES='i486 i686 amd64'
    23  ```
    24  
    25  The architecture identifiers can be found by browsing Gentoo's
    26  [releases][] for `autobuilds/latest-stage3-{arch}.txt`.  Examples
    27  include:
    28  
    29  * `amd64` (the default)
    30  * `arm64`
    31  * `arm7a`
    32  * `i486`
    33  * `i686`
    34  * `ppc64-64ul`
    35  
    36  and many more.
    37  
    38  ## Getting Gentoo's Release Engineering public key
    39  
    40  If `make rootfs-….tar.gz` gives an error like:
    41  
    42  ```
    43  gpg --verify downloads/stage3-amd64-current.tar.bz2.DIGESTS.asc
    44  gpg: Signature made Thu 14 Jan 2016 09:00:11 PM EST using RSA key ID 2D182910
    45  gpg: Can't check signature: public key not found
    46  ```
    47  
    48  you will need to [add the missing public key to your
    49  keystore][gentoo-signatures].  One way to do that is by [asking a
    50  keyserver][recv-keys]:
    51  
    52  ```
    53  $ gpg --keyserver pool.sks-keyservers.net --recv-keys 2D182910
    54  ```
    55  
    56  [Gentoo]: https://www.gentoo.org/
    57  [gentoo-signatures]: https://www.gentoo.org/downloads/signatures/
    58  [recv-keys]: https://www.gnupg.org/documentation/manuals/gnupg/Operational-GPG-Commands.html
    59  [releases]: http://distfiles.gentoo.org/releases/
    60  [stage3-amd64]: http://distfiles.gentoo.org/releases/amd64/autobuilds/