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<section id="capture-kernel-boot-messages-in-the-journal">
<span id="kernel-boot-msg"></span><h1>Capture Kernel Boot Messages in the Journal<a class="headerlink" href="#capture-kernel-boot-messages-in-the-journal" title="Link to this heading"></a></h1>
<p>By default Clear Linux OS does not capture kernel boot messages in the journal logs,
where theyre reported as “Missed” messages. This design decision was made
to provide a faster boot performance. On the other hand, if you wish to
see the messages, follow this guide.</p>
<p>Heres an example a journal log with “Missed” messages:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="linenos">1</span><span class="go">-- Reboot --</span>
<span class="linenos">2</span><span class="go">Apr 10 19:55:43 kernel systemd-journald[300]: Journal started</span>
<span class="linenos">3</span><span class="go">Apr 10 19:55:43 kernel systemd-journald[300]: Runtime Journal (/run/log/journal/d01862ca79d1064ea379cd715cfdd53a) is 5.8M, max 47.0M, 41.1M free.</span>
<span class="hll"><span class="linenos">4</span><span class="go">Apr 10 19:55:43 kernel systemd-journald[300]: Missed 2233 kernel messages</span>
</span><span class="linenos">5</span><span class="go">Apr 10 19:55:43 kernel systemd[1]: Started Journal Service.</span>
</pre></div>
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<ul class="simple">
<li><p><a class="reference internal" href="#prerequisites" id="id1">Prerequisites</a></p></li>
<li><p><a class="reference internal" href="#enable-journaling-of-kernel-boot-messages" id="id2">Enable journaling of kernel boot messages</a></p></li>
<li><p><a class="reference internal" href="#alternative" id="id3">Alternative</a></p></li>
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<section id="prerequisites">
<h2><a class="toc-backref" href="#id1" role="doc-backlink">Prerequisites</a><a class="headerlink" href="#prerequisites" title="Link to this heading"></a></h2>
<ul class="simple">
<li><p><cite>systemd-journald</cite> version 245 and higher</p></li>
</ul>
</section>
<section id="enable-journaling-of-kernel-boot-messages">
<h2><a class="toc-backref" href="#id2" role="doc-backlink">Enable journaling of kernel boot messages</a><a class="headerlink" href="#enable-journaling-of-kernel-boot-messages" title="Link to this heading"></a></h2>
<ol class="arabic">
<li><p>Open a terminal window.</p></li>
<li><p>Create a base journald configuration file.</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>sudo<span class="w"> </span>mkdir<span class="w"> </span>-p<span class="w"> </span>/etc/systemd/journald.conf.d
sudo<span class="w"> </span>cp<span class="w"> </span>/usr/lib/systemd/journald.conf.d/clear.conf<span class="w"> </span>/etc/systemd/journald.conf.d/
</pre></div>
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</li>
<li><p>Append <strong class="command">BootKMsg=true</strong> to it.</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span><span class="nb">echo</span><span class="w"> </span><span class="s2">&quot;BootKMsg=true&quot;</span><span class="w"> </span><span class="p">|</span><span class="w"> </span>sudo<span class="w"> </span>tee<span class="w"> </span>-a<span class="w"> </span>/etc/systemd/journald.conf.d/clear.conf
</pre></div>
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</li>
<li><p>Reboot.</p></li>
</ol>
<div class="admonition tip">
<p class="admonition-title">Tip</p>
<p>If you need to increase the kernel buffer length (for example, 1M), do this:</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>sudo<span class="w"> </span>mkdir<span class="w"> </span>-p<span class="w"> </span>/etc/kernel/cmdline.d/
<span class="nb">echo</span><span class="w"> </span><span class="s2">&quot;log_buf_len=1M&quot;</span><span class="w"> </span><span class="p">|</span><span class="w"> </span>sudo<span class="w"> </span>tee<span class="w"> </span>/etc/kernel/cmdline.d/log_buf_len.conf
sudo<span class="w"> </span>clr-boot-manager<span class="w"> </span>update
</pre></div>
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<section id="alternative">
<h2><a class="toc-backref" href="#id3" role="doc-backlink">Alternative</a><a class="headerlink" href="#alternative" title="Link to this heading"></a></h2>
<p>An alternative is to use <strong class="command">dmesg</strong>.</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span>sudo<span class="w"> </span>dmesg
</pre></div>
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<li><a class="reference internal" href="#">Capture Kernel Boot Messages in the Journal</a><ul>
<li><a class="reference internal" href="#prerequisites">Prerequisites</a></li>
<li><a class="reference internal" href="#enable-journaling-of-kernel-boot-messages">Enable journaling of kernel boot messages</a></li>
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