Quick Start

The primary aim of the Mezzotint tool is to minimize your container’s size by eliminating anything considered “junk” — items that are never used, unnecessary, and serve no purpose within your container.

Attention

This document does not explains how to provision a root filesystem with additional software.

To quickly start, you should already have somewhere a mounted container root filesystem with installed Emacs without X11 support (terminal only). For the process, we recommend to use Buildah, but you may choose other similar tools. If you don’t know how to do this, navigate to Detailed Usage for full guidance.

And so if you’ve already provisioned and configured your forthcoming container mountpoint with the application but haven’t shared it yet, run Mezzotint on that mountpoint, specifying it as the system root, like so:

mezzotint -a free -x /usr/bin/emacs-nox -r /path/to/the/mountpoint -t

The command above will:

-a: try to automatically resolve all necessary packages
-x: for /usr/bin/emacs-nox binary inside your container
-r: within the mounted root filesystem /path/to/the/mountpoint
-t: but will not apply anything just yet (dry-run)

Alongside detailed listings of each file in the system, the output should conclude with a summary akin to the following:

Removed 6442 files, releasing 331.4 MB of a disk space
Preserved 2281 files, taking 289.2 MB of a disk space
Potentially 22 junk files, taking 2.2 MB of a disk space
Kept 37 packages as follows:
    emacs-bin-common, emacs-common, emacs-nox, emacsen-common, libacl1, libasound2,
    libasound2-data, libc6, libcap2, libcrypt1, libdbus-1-3, libffi8, libgcc-s1,
    libgcrypt20, libgmp10, libgnutls30, libgpg-error0, libgpm2, libhogweed6, libicu70,
    libidn2-0, libjansson4, liblcms2-2, liblz4-1, liblzma5, libnettle8, libp11-kit0,
    libpcre2-8-0, libselinux1, libstdc++6, libsystemd0, libtasn1-6, libtinfo6,
    libunistring2, libxml2, libzstd1, zlib1g

[21/09/2023 15:16:06] - WARN: This was a dry-run. Changes were not applied.

Obviously keeping 300M container for Emacs is not very optimal, but is good start. Once you think this is acceptable result, re-run the same command, without --dry-run option (-t). Your container still should work. Hopefully. :-)