John3-16: Added Categories: Development, Installation, Booting

2025-12-21T09:19:44Z

Added Categories: Development, Installation, Booting

← Older revision		Revision as of 09:19, 21 December 2025
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	<p>See [[Netboot Alpine Linux using iPXE]] and adjust paths as necessary.</p>		<p>See [[Netboot Alpine Linux using iPXE]] and adjust paths as necessary.</p>

			[[Category:Development]]
			[[Category:Installation]]
			[[Category:Booting]]

Danielfdickinson: Add new topic "Testing modified install images and packages"

2022-07-10T05:05:03Z

Add new topic "Testing modified install images and packages"

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<h2>Overview</h2>
<p>Modifying packages that are part of the install diskless boot (e.g. on install media), or the parameters that can be accepted by the boot process, is a little more involved than modifying individual packages, especially for netboot images. This author discovered that then when working on [https://gitlab.alpinelinux.org/alpine/mkinitfs/-/issues/26 feat: answerfile kernel cmdline parameter (#26) · Issues · alpine / mkinitfs · GitLab] an issue he opened to request / offer to develop an improvement to unattended installation by adding the option of applying a <code>setup-alpine</code> 'answerfile' automatically via netboot, by providing a URL to a new <code>answerfile</code> kernel commandline parameter.</p>
<h2 class="atx" id="the-easy-part">The easy part</h2>
<ul>
<li>Update the list of options accepted by the installer using the kernel command line by modifying [https://gitlab.alpinelinux.org/alpine/mkinitfs mkinitfs] <code>initramfs-init.in</code> and updating the <code>man</code> page in <code>mkinitfs-bootparam.7.in</code>.</li>
<li>Install the new <code>mkinitfs</code> into one's build environment using <code>make install</code> in <code>mkinitfs</code>.</li>
<li>Build a new image using <code>scripts/mkimage.sh</code> from [https://gitlab.alpinelinux.org/alpine/aports aports] with the appropriate parameters.</li>
<li>You now have an image that will accept your new parameter.</li>
</ul>
<h2 class="atx" id="challenge-1">Challenge #1</h2>
<ul>
<li>In the case of <code>answerfile</code> an additional change needs to be make to the <code>firstboot</code> initscript, which is part of the <code>openrc</code> package.</li>
<li>That means building a new <code>openrc</code> package and getting it into the generated image.</li>
<li>To do that one has to point <code>scripts/mkimage.sh</code> at the package repository created when building the modified <code>openrc</code> package.</li>
<li>This is sufficient for images where all the packages used during boot and install are present on the install media.</li>
</ul>
<h2 class="atx" id="challenge-2-netboot">Challenge #2 (netboot)</h2>
<ul>
<li>For netboot, however, the process is more involved because the <code>openrc</code> package has to be downloaded from an external repository during the boot process.</li>
<li>This would seem easy; one might think you one could just supply put the <code>packages</code> directory created during the <code>openrc</code> build on a web server and using the <code>alpine_repo=<URI_of_repo></code>, but the problem is that <code>alpine_repo</code> only accepts a single repository.</li>
<li>In addition the package list must be signed by a key which appears in the image (that part is easy using the <code>mkimage.sh</code> parameters).</li>
<li>This means one must have include <em>all</em> the packages netboot and install will require in the new repository.</li>
<li>There is one more gotcha; One must include all the <em>dependencies</em> for the packages in the repository or the packages will fail to install.</li>
</ul>
<h3 class="atx" id="one-method-of-creating-the-necessary-signed-repository">One method of creating the necessary signed repository</h3>
<h4 class="atx" id="identify-all-the-base-packages-needed-by-netboot">Identify all the base packages needed by netboot</h4>
<ul>
<li>In the <code>mkinitfs</code> repository issue <code>grep pkgs initfamfs-init.in</code> and make note of all the packages that may be used by the initramfs.</li>
<li>In <code>aports</code>, <code>grep apks scripts/*</code>. This will identify all base packages added by the <code>mkimage.sh</code> script.</li>
<li>You also need <code>linux-lts linux-virt wireless-regdb scanelf alpine-conf alpine-base openssl</code></li>
</ul>
<h4 class="atx" id="identify-all-the-dependencies-of-the-base-packages">Identify all the dependencies of the base packages</h4>
<ul>
<li><p>Create a file with the list of base packages on a single line, separated by spaces. For example a file named <code>~/base-packages.lst</code> containing:</p>

<pre>package1 package2 package3</pre>

</li>
<li><p>Install the package <code>lua-aports</code></p>
</li>
<li><p>From a package directory in a package from <code>aports</code>, issue the following command:</p>

<pre>ap recursive-deps $(cat ~/base-packages.lst) >~/base-deps.lst</pre>

</li>
</ul>
<h4 class="atx" id="build-all-required-packages">Build all required packages</h4>
<h5 class="atx" id="create-required-list-of-package-directories-in-aports">Create required list of package directories in <code>aports</code></h5>
<ul>
<li><p>Take the list of base packages and dependencies above and create a single file with all packages on a single line, separated by spaces. For <code>~/base-deps.lst</code> above you could do:</p>

<pre>cat ~/base-deps.lst ~/base-pkgs.lst | tr $'\n' ' ' >~/oneline-deps.lst</pre>

</li>
<li><p>From a package directory in a package from <code>aports</code>, issue the following command:</p>

<pre>ap builddirs $(cat ~/oneline-deps.lst) >~/packages-to-build.lst</pre>

</li>
</ul>
<h5 class="atx" id="create-a-directory-for-the-package-repository">Create a directory for the package repository</h5>
<pre><code class="fenced-code-block language-shell">mkdir -p ~/packages/main</code></pre>
<h5 class="atx" id="add-this-directory-to-the-system-apk-repositories">Add this directory to the system APK repositories</h5>
<ul>
<li><p><strong>NOTE</strong>: This will break things if you are not running latest (edge) Alpine in your build environment</p>
</li>
<li><p>Assuming your user home dir is <code>/home/user</code>, then to the file <code>/etc/apk/repositories</code> add</p>

<pre>/home/user/packages/main</pre>

</li>
</ul>
<h5 class="atx" id="build-the-packages">Build the packages</h5>

<pre>cd ~
for pdir in $(cat ~/packages-to-build.lst); do (cd $pdir && abuild -r -m | tee -a ~/build.log); done</pre>

<h4 class="atx" id="build-a-netboot-image">Build a netboot image</h4>
<p>From the <code>aports</code> directory:</p>

<pre>./scripts/mkimage.sh --profile netboot --repository /home/user/packages/main</pre>

<h3 class="atx" id="copy-to-your-netboot-server-and-netboot">Copy to your netboot server and netboot</h3>

<p>See [[Netboot Alpine Linux using iPXE]] and adjust paths as necessary.</p>

Testing modified install images and packages - Revision history

John3-16: Added Categories: Development, Installation, Booting

Danielfdickinson: Add new topic "Testing modified install images and packages"