XT-CREATE-XEN-CONFIG(8)

📦
version 4.9.2 · 4 versions
, in debian bookworm, ubuntu noble

💖 xt-create-xen-config(8) — the manual, but make it make sense 💖

okay bestie, so this is the xt-create-xen-config page from the Perl Programmers Reference Guide. It's a lil script with a big job and honestly? iconic. Let's get into it. ✨

🌸 NAME 🌸

xt-create-config — creates a Xen configuration file for a brand new guest. That's it, that's the whole vibe. 🎀

✨ SYNOPSIS ✨

xt-create-config [options]

Filename Options:

  --output     Specify the output directory to use.
  --extension  Specify the file extension to use.

General Options:

  --admins     Specify some administrator accounts which should be
              created for use by the xen-shell.

  --template   Specify the template file to use when creating the
              Xen configuration file.

Help Options:

 --help        Show this scripts help information.
 --manual      Read this scripts manual.
 --version     Show the version number and exit.

Debugging Options:

 --verbose  Be verbose in our execution.

All other options from xen-create-image, such as the new IP address(es)
to give to the new instance, will be passed as environmental variables.

so yeah, you run it, you give it options, and the rest of the stuff gets handed over through environmental variables. cute, chaotic, we love her. 💅

🦋 ABOUT 🦋

okay so here's the tea: this script doesn't just wake up and do stuff on its own. It gets invoked by xen-create-image — but only after that script has already created and customised a new Xen guest. At that point our girl takes over and is responsible for creating the configuration file which Xen will use to start the instance. main character energy fr fr. 👑

That configuration file gets created in the directory /etc/xen, and it uses a template file to figure out how it should be built.

By default, the script uses /etc/xen-tools/xm.tmpl as its input. no cap. 🫶

🌈 INVOCATION 🌈

The way this actually happens: this script will be invoked by the xen-create-image script, rather than directly by you. periodt.

Why? Because it expects to receive the values to insert into the output template in as environmental variables. It's not built for a solo debut, it's built for the group chat. 💀

Technically you could execute it manually via a long command line, but lowkey that's error-prone and probably not useful. Her words, not mine:

hostname=foo.my.flat ip=192.168.1.2 ... xm-create-xen-config \
  --output=/etc/xen --template=/etc/xen-tools/xm.tmpl

like... look at that. exhausting. 🙈

🧚 ARGUMENT PASSING 🧚

So this script gets invoked with a full copy of the arguments from xen-create-image sitting in its environment, PLUS several command line arguments of its own.

That has several implications for customization, bestie — listen up:

If you wanna set up a new variable in the output template, like foo=bar, you could update the script to include ${foo}, and then invoke xen-create-image with that environmental variable set. Like so:

$ foo=bar xen-create-image --hostname=test.my.flat ...

The environment will be duplicated/inheritted by this script when it is executed, and your variable will be included in the output file. slay. 🎀

Heads up: for the deets on the template file syntax, go look at the documentation for the Text::Template perl module. (If you have the perldoc package installed, you can read it with perldoc Text::Template.) 🌸

💜 AUTHORS 💜

👑 LICENSE 👑

Copyright (c) 2005-2009 by Steve Kemp, (c) 2010-2012 by The Xen-Tools Development Team. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The LICENSE file contains the full text of the license. 💖

and that's the whole page, bestie!! version 4.9.2, dated 2023-02-06, live from the Perl Programmers Reference Guide. tysm for reading, go forth and configure ur Xen guests responsibly. 🦋✨🎀

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