Edit File: dracut-rhel6.html
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>dracut</title><link rel="stylesheet" href="http://docs.redhat.com/docs/en-US/Common_Content/css/default.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><style type="text/css"> body { background-image: url('http://docbook.sourceforge.net/release/images/draft.png'); background-repeat: no-repeat; background-position: top left; /* The following properties make the watermark "fixed" on the page. */ /* I think that's just a bit too distracting for the reader... */ /* background-attachment: fixed; */ /* background-position: center center; */ }</style></head><body><div class="book" title="dracut"><div class="titlepage"><div><div><h1 class="title"><a id="idp43456"></a><span class="inlinemediaobject"><img src="dracut.png" /></span>dracut</h1></div><div><div class="author"><h3 class="author"><span class="firstname">Harald</span> <span class="surname">Hoyer</span></h3></div></div><div><p class="copyright">Copyright © 2010 Harald Hoyer</p></div><div><p class="pubdate">2010</p></div></div><hr /></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="chapter"><a href="#idp176512">1. User Manual</a></span></dt><dd><dl><dt><span class="section"><a href="#create_image">Creating an initramfs Image</a></span></dt><dd><dl><dt><span class="section"><a href="#lsinitrd">Inspecting the Contents</a></span></dt><dt><span class="section"><a href="#add_dracut_modules">Adding dracut Modules</a></span></dt><dt><span class="section"><a href="#omit_dracut_modules">Omitting dracut Modules</a></span></dt><dt><span class="section"><a href="#add_kernel_modules">Adding Kernel Modules</a></span></dt></dl></dd><dt><span class="section"><a href="#boot_parameters">Boot parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#root_device">Specifying the root Device</a></span></dt><dt><span class="section"><a href="#keyboard">Keyboard Settings</a></span></dt><dt><span class="section"><a href="#force_kernel_modules">Force loading of Kernel Modules</a></span></dt><dt><span class="section"><a href="#blacklist_kernel_modules">Blacklisting Kernel Modules</a></span></dt><dt><span class="section"><a href="#speedup">Speeding up the Boot Process</a></span></dt><dt><span class="section"><a href="#Injecting">Injecting custom Files</a></span></dt></dl></dd><dt><span class="section"><a href="#NetworkBoot">Network Boot</a></span></dt><dd><dl><dt><span class="section"><a href="#reduce">Reducing the Image Size</a></span></dt></dl></dd><dt><span class="section"><a href="#troubleshooting">Troubleshooting</a></span></dt><dd><dl><dt><span class="section"><a href="#identifying-your-problem-area">Identifying your problem area</a></span></dt><dt><span class="section"><a href="#information-to-include-in-your-report">Information to include in your report</a></span></dt><dt><span class="section"><a href="#debugging-dracut">Debugging dracut</a></span></dt></dl></dd></dl></dd><dt><span class="appendix"><a href="#idp3483904">A. Man Pages</a></span></dt><dd><dl><dt><span class="section"><a href="#dracut.man">dracut</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracut8">dracut</a></span><span class="refpurpose"> — create initial ramdisk images for preloading modules</span></dt></dl></dd><dt><span class="section"><a href="#dracut.conf">dracut.conf</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracutconf5">dracut.conf</a></span><span class="refpurpose"> — configuration file(s) for dracut</span></dt></dl></dd><dt><span class="section"><a href="#dracut.kernel">dracut.kernel</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracutkernel7">dracut</a></span><span class="refpurpose"> — dracut kernel command line options</span></dt></dl></dd></dl></dd></dl></div><div class="chapter" title="Chapter 1. User Manual"><div class="titlepage"><div><div><h2 class="title"><a id="idp176512"></a>Chapter 1. User Manual</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#create_image">Creating an initramfs Image</a></span></dt><dd><dl><dt><span class="section"><a href="#lsinitrd">Inspecting the Contents</a></span></dt><dt><span class="section"><a href="#add_dracut_modules">Adding dracut Modules</a></span></dt><dt><span class="section"><a href="#omit_dracut_modules">Omitting dracut Modules</a></span></dt><dt><span class="section"><a href="#add_kernel_modules">Adding Kernel Modules</a></span></dt></dl></dd><dt><span class="section"><a href="#boot_parameters">Boot parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#root_device">Specifying the root Device</a></span></dt><dt><span class="section"><a href="#keyboard">Keyboard Settings</a></span></dt><dt><span class="section"><a href="#force_kernel_modules">Force loading of Kernel Modules</a></span></dt><dt><span class="section"><a href="#blacklist_kernel_modules">Blacklisting Kernel Modules</a></span></dt><dt><span class="section"><a href="#speedup">Speeding up the Boot Process</a></span></dt><dt><span class="section"><a href="#Injecting">Injecting custom Files</a></span></dt></dl></dd><dt><span class="section"><a href="#NetworkBoot">Network Boot</a></span></dt><dd><dl><dt><span class="section"><a href="#reduce">Reducing the Image Size</a></span></dt></dl></dd><dt><span class="section"><a href="#troubleshooting">Troubleshooting</a></span></dt><dd><dl><dt><span class="section"><a href="#identifying-your-problem-area">Identifying your problem area</a></span></dt><dt><span class="section"><a href="#information-to-include-in-your-report">Information to include in your report</a></span></dt><dt><span class="section"><a href="#debugging-dracut">Debugging dracut</a></span></dt></dl></dd></dl></div><div class="section" title="Creating an initramfs Image"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="create_image"></a>Creating an initramfs Image</h2></div></div></div><p>To create a initramfs image, the most simple command is:</p><pre class="screen"># dracut</pre><p>This will generate a general purpose initramfs image, with all possible functionality resulting of the combination of the installed dracut modules and system tools. The image is /boot/initramfs-<em class="replaceable"><code><kernel version></code></em>.img and contains the kernel modules of the currently active kernel with version <em class="replaceable"><code><kernel version></code></em>.</p><p>If the initramfs image already exists, dracut will display an error message, and to overwrite the existing image, you have to use the <code class="option">--force</code> option. </p><pre class="screen"># dracut --force</pre><p>If you want to specify another filename for the resulting image you would issue a command like:</p><pre class="screen"># dracut foobar.img</pre><p>To generate an image for a specific kernel version, the command would be:</p><pre class="screen"># dracut foobar.img 2.6.40-1.rc5.f20</pre><p>A shortcut to generate the image at the default location for a specific kernel version is:</p><pre class="screen"># dracut '' 2.6.40-1.rc5.f20</pre><p>If you want to create lighter, smaller initramfs images, you may want to specify the <code class="option">--host-only</code> or <code class="option">-H</code> option. Using this option, the resulting image will contain only those dracut modules, kernel modules and filesystems, which are needed to boot this specific machine. This has the drawback, that you can't put the disk on another controller or machine, and that you can't switch to another root filesystem, without recreating the initramfs image. The usage of the <code class="option">--host-only</code> option is only for experts and you will have to keep the broken pieces. At least keep a copy of a general purpose image (and corresponding kernel) as a fallback to rescue your system.</p><div class="section" title="Inspecting the Contents"><div class="titlepage"><div><div><h3 class="title"><a id="lsinitrd"></a>Inspecting the Contents</h3></div></div></div><p>To see the contents of the image created by dracut, you can use the <span class="command"><strong>lsinitrd</strong></span> tool.</p><pre class="screen"># lsinitrd /boot/initramfs-$(uname -r).img | less</pre><p>To display the contents of a file in the initramfs also use the <span class="command"><strong>lsinitrd</strong></span> tool:</p><pre class="screen"># lsinitrd /boot/initramfs-$(uname -r).img /etc/ld.so.conf include ld.so.conf.d/*.conf</pre></div><div class="section" title="Adding dracut Modules"><div class="titlepage"><div><div><h3 class="title"><a id="add_dracut_modules"></a>Adding dracut Modules</h3></div></div></div><p>Some dracut modules are turned off by default and have to be activated manually. You can do this by adding the dracut modules to the configuration file <code class="filename">/etc/dracut.conf</code> or <code class="filename">/etc/dracut.conf.d/myconf.conf</code>. See the man page <a class="xref" href="#dracutconf5" title="dracut.conf"><span class="refentrytitle">dracut.conf</span>(5)</a>. You can also add dracut modules on the command line by using the <code class="option">-a</code> or <code class="option">--add</code> option:</p><pre class="screen"># dracut --add bootchart initramfs-bootchart.img</pre><p>To see a list of available dracut modules, issue the command:</p><pre class="screen"># for mod in /usr/share/dracut/modules.d/*; do echo ${mod##*/??}; done</pre></div><div class="section" title="Omitting dracut Modules"><div class="titlepage"><div><div><h3 class="title"><a id="omit_dracut_modules"></a>Omitting dracut Modules</h3></div></div></div><p>Sometimes you don't want a dracut module to be included for reasons of speed, size or functionality. To do this, either specify the <code class="envar">omit_dracutmodules</code> variable in the <code class="filename">dracut.conf</code> or <code class="filename">/etc/dracut.conf.d/myconf.conf</code> configuration file (see man page <a class="xref" href="#dracutconf5" title="dracut.conf"><span class="refentrytitle">dracut.conf</span>(5)</a>), or use the <code class="option">-o</code> or <code class="option">--omit</code> option on the command line:</p><pre class="screen"># dracut -o "multipath lvm" no-multipath-lvm.img</pre></div><div class="section" title="Adding Kernel Modules"><div class="titlepage"><div><div><h3 class="title"><a id="add_kernel_modules"></a>Adding Kernel Modules</h3></div></div></div><p>If you need a special kernel module in the initramfs, which is not automatically picked up by dracut, you have the use the <code class="option">--add-drivers</code> option on the command line or the drivers vaiable in the <code class="filename">/etc/dracut.conf</code> or <code class="filename">/etc/dracut.conf.d/myconf.conf</code> configuration file (see man page <a class="xref" href="#dracutconf5" title="dracut.conf"><span class="refentrytitle">dracut.conf</span>(5)</a>):</p><pre class="screen"># dracut --add-drivers mymod initramfs-with-mymod.img</pre><p>dracut searches for kernel modules in </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p><code class="filename">/lib/modules/<kernel version>/kernel/drivers</code></p></li><li class="listitem"><p><code class="filename">/lib/modules/<kernel version>/updates</code></p></li><li class="listitem"><p><code class="filename">/lib/modules/<kernel version>/extra</code></p></li><li class="listitem"><p><code class="filename">/lib/modules/<kernel version>/weak-updates</code></p></li></ul></div></div></div><div class="section" title="Boot parameters"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="boot_parameters"></a>Boot parameters</h2></div></div></div><p>The generated initramfs.img file normally does not contain any system configuration files (except for some special exceptions), so the configuration has to be done on the kernel command line. With this flexibility, you can easily boot from a changed root partition, without the need to recompile the initramfs image. So, you could completly change your root partition (move it inside a md raid with encryption and LVM on top), as long as you specify the correct filesystem <code class="varname">LABEL</code> or <code class="varname">UUID</code> on the kernel command line for your root device, dracut will find it and boot from it.</p><p>The kernel command line usually can be configured in <code class="filename">/boot/grub/grub.conf</code>, if grub is your bootloader and it also can be edited in the real boot process in the grub menu.</p><p>The kernel command line can also be provided by the dhcp server with the root-path option. See <a class="xref" href="#NetworkBoot" title="Network Boot">the section called “Network Boot”</a>.</p><p>For a full reference of all kernel command line parameters, see the <a class="xref" href="#dracutconf5" title="dracut.conf"><span class="refentrytitle">dracut.conf</span>(5)</a> or <a class="xref" href="#dracut8" title="dracut"><span class="refentrytitle">dracut</span>(8)</a> man page.</p><div class="section" title="Specifying the root Device"><div class="titlepage"><div><div><h3 class="title"><a id="root_device"></a>Specifying the root Device</h3></div></div></div><p>This is the only option dracut really needs to boot from your root partition. Because your root partition can live in various environments, there are a lot of formats for the <code class="envar">root=</code> option. The most basic one is <code class="envar">root=<em class="replaceable"><code><path to device node></code></em></code>:</p><pre class="screen">root=/dev/sda2</pre><p>Because device node names can change, dependent on the drive ordering, you are encouraged to use the filesystem identifier (UUID) or filesystem label (LABEL) to specify your root partition:</p><pre class="screen">root=UUID=19e9dda3-5a38-484d-a9b0-fa6b067d0331</pre><p>or</p><pre class="screen">root=LABEL=myrootpartitionlabel</pre><p>To see all <code class="envar">UUID</code>s or <code class="envar">LABEL</code>s on your system, do:</p><pre class="screen"># ls -l /dev/disk/by-uuid</pre><p>or</p><pre class="screen"># ls -l /dev/disk/by-label</pre><p>If your root partition is on the network see <a class="xref" href="#NetworkBoot" title="Network Boot">the section called “Network Boot”</a>.</p></div><div class="section" title="Keyboard Settings"><div class="titlepage"><div><div><h3 class="title"><a id="keyboard"></a>Keyboard Settings</h3></div></div></div><p>If you have to input passwords for encrypted disk volumes, you might want to set the keyboard layout and specify a display font.</p><p>A typical german kernel command would contain:</p><pre class="screen">LANG=de_DE.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=de-latin1-nodeadkeys</pre></div><div class="section" title="Force loading of Kernel Modules"><div class="titlepage"><div><div><h3 class="title"><a id="force_kernel_modules"></a>Force loading of Kernel Modules</h3></div></div></div><p>dracut can force load a kernel module with the <code class="envar">rdloaddriver=<em class="replaceable"><code><drivername></code></em></code> kernel command line parameter, if the kernel module is included in the initramfs (see previous section). If you want the kernel module to be force loaded after all automatic loading modules have been loaded, use the <code class="envar">rdrdinsmodpost=<em class="replaceable"><code><drivername></code></em></code> kernel command line parameter.</p></div><div class="section" title="Blacklisting Kernel Modules"><div class="titlepage"><div><div><h3 class="title"><a id="blacklist_kernel_modules"></a>Blacklisting Kernel Modules</h3></div></div></div><p>Sometimes it is required to prevent the automatic kernel module loading of a specific kernel module. To do this, just add <code class="envar">rd.blacklist=<em class="replaceable"><code><kernel module name></code></em></code>, with <em class="replaceable"><code><kernel module name></code></em> not containing the <code class="filename">.ko</code> suffix, to the kernel command line. For example:</p><pre class="screen">rdblacklist=mptsas rdblacklist=nouveau</pre><p>The option can be specified multiple times on the kernel command line.</p></div><div class="section" title="Speeding up the Boot Process"><div class="titlepage"><div><div><h3 class="title"><a id="speedup"></a>Speeding up the Boot Process</h3></div></div></div><p>If you want to speed up the boot process, you can specify as much information for dracut on the kernel command as possible. For example, you can tell dracut, that you root partition is not on a <acronym class="acronym">LVM</acronym> volume or not on a raid partition, or that it lives inside a specific crypto <acronym class="acronym">LUKS</acronym> encrypted volume. By default, dracut searches everywhere. A typical dracut kernel command line for a plain primary or logical partition would contain:</p><pre class="screen">rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM</pre><p>This turns off every automatic assembly of <acronym class="acronym">LVM</acronym>, <acronym class="acronym">MD</acronym> raids, <acronym class="acronym">DM</acronym> raids and crypto <acronym class="acronym">LUKS</acronym>.</p><p>Of course, you could also omit the dracut modules in the initramfs creation process, but then you would lose the posibility to turn it on on demand.</p></div><div class="section" title="Injecting custom Files"><div class="titlepage"><div><div><h3 class="title"><a id="Injecting"></a>Injecting custom Files</h3></div></div></div><p>To add your own files to the initramfs image, you have several possibilities.</p><p>The <code class="option">--include</code> option let you specify a source path and a target path. For example</p><pre class="screen"># dracut --include cmdline-preset /etc/cmdline initramfs-cmdline-pre.img</pre><p>will create an initramfs image, where the file cmdline-preset will be copied inside the initramfs to <code class="filename">/etc/cmdline</code>. <code class="option">--include</code> can only be specified once.</p><pre class="screen"># mkdir overlay # mkdir overlay/etc # mkdir overlay/etc/conf.d # echo "ip=auto" >> overlay/etc/cmdline # echo export TESTVAR=testtest >> overlay/etc/conf.d/testvar.conf # echo export TESTVAR=testtest >> overlay/etc/conf.d/testvar.conf # tree overlay/ overlay/ └── etc ├── cmdline └── conf.d └── testvar.conf # dracut --include overlay / initramfs-overlay.img</pre><p>This will put the contents of the overlay directory into the root of the initramfs image.</p><p>The <code class="option">--install</code> option let you specify several files, which will get installed in the initramfs image at the same location, as they are present on initramfs creation time.</p><pre class="screen"># dracut --install 'strace fsck.ext3 ssh' initramfs-dbg.img</pre><p>This will create an initramfs with the <span class="command"><strong>strace</strong></span>, <span class="command"><strong>fsck.ext3</strong></span> and <span class="command"><strong>ssh</strong></span> executables, together with the libraries needed to start those. The <code class="option">--install</code> option can be specified multiple times.</p></div></div><div class="section" title="Network Boot"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="NetworkBoot"></a>Network Boot</h2></div></div></div><p>If your root partition is on a network drive, you have to have the network dracut modules installed to create a network aware initramfs image.</p><p>On a Red Hat Enterprise Linux or Fedora system, this means, you have to install the <code class="filename">dracut-network</code> rpm package:</p><pre class="screen"># yum install dracut-network</pre><p>The resulting initramfs image can be served by a boot manager residing on your local hard drive or it can be served by a <acronym class="acronym">PXE</acronym>/<acronym class="acronym">TFTP</acronym> server.</p><p>How to setup your <acronym class="acronym">PXE</acronym>/<acronym class="acronym">TFTP</acronym> server can be found in the <a class="ulink" href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/" target="_top">Red Hat Enterprise Linux Storage Administration Guide</a>.</p><p>If you specify <code class="envar">rd.ip=auto</code> on the kernel command line, then dracut asks a dhcp server about the ip adress for the machine. The dhcp server can also serve an additional root-path, which will set the root device for dracut. With this mechanism, you have static configuration on your client machine and a centralized boot configuration on your <acronym class="acronym">TFTP</acronym>/<acronym class="acronym">DHCP</acronym> server. If you can't pass a kernel command line, then you can inject <code class="filename">/etc/cmdline</code>, with a method described in <a class="xref" href="#Injecting" title="Injecting custom Files">the section called “Injecting custom Files”</a>. </p><div class="section" title="Reducing the Image Size"><div class="titlepage"><div><div><h3 class="title"><a id="reduce"></a>Reducing the Image Size</h3></div></div></div><p>To reduce the size of the initramfs, you should create it with by ommitting all dracut modules, which you know, you don't need to boot the machine.</p><p>You can also specify the exact dracut and kernel modules to produce a very tiny initramfs image.</p><p>For example for a <acronym class="acronym">NFS</acronym> image, you would do:</p><pre class="screen"># dracut -m "nfs network base" initramfs-nfs-only.img</pre><p>Then you would boot from this image with your target machine and reduce the size once more by creating it on the target machine with the <code class="option">--host-only</code> option:</p><pre class="screen"># dracut -m "nfs network base" --host-only initramfs-nfs-host-only.img</pre><p>This will reduce the size of the initramfs image significantly.</p></div></div><div class="section" title="Troubleshooting"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="troubleshooting"></a>Troubleshooting</h2></div></div></div><p>If the boot process does not succeed, you have several options to debug the situation. Some of the basic operations are covered here. For more information you should also visit: <a class="ulink" href="http://fedoraproject.org/wiki/How_to_debug_Dracut_problems" target="_top">http://fedoraproject.org/wiki/How_to_debug_Dracut_problems</a></p><div class="section" title="Identifying your problem area"><div class="titlepage"><div><div><h3 class="title"><a id="identifying-your-problem-area"></a>Identifying your problem area</h3></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>Remove ''rhgb'' and ''quiet'' from the kernel command line </p></li><li class="listitem"><p>Add ''rdshell'' to the kernel command line. This will present a shell should dracut be unable to locate your root device </p></li><li class="listitem"><p>Add ''rdshell rdinitdebug'' to the kernel command line so that dracut shell commands are printed as they are executed </p></li><li class="listitem"><p>With dracut >= 002-11, you can inspect the rdinitdebug output with: </p><pre class="screen"># less /init.log # dmesg | less</pre></li></ol></div></div><div class="section" title="Information to include in your report"><div class="titlepage"><div><div><h3 class="title"><a id="information-to-include-in-your-report"></a>Information to include in your report</h3></div></div></div><div class="section" title="All bug reports"><div class="titlepage"><div><div><h4 class="title"><a id="all-bug-reports"></a>All bug reports</h4></div></div></div><p>In all cases, the following should be mentioned and attached to your bug report: </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>The exact kernel command-line used. Typically from the bootloader configuration file (e.g. <code class="filename">/etc/grub.conf</code>) or from <code class="filename">/proc/cmdline</code>.</p></li><li class="listitem"><p>A copy of your disk partition information from <code class="filename">/etc/fstab</code>, which might be obtained booting an old working initramfs or a rescue medium.</p></li><li class="listitem"><p>A device listing from device-mapper. This can be obtained by running the command </p><pre class="screen"># dmsetup ls --tree</pre></li><li class="listitem"><p>A list of block device attributes including vol_id compatible mode. This can be obtained by running the commands: </p><pre class="screen"># blkid -p # blkid -p -o udev</pre></li><li class="listitem"><p>Turn on dracut debugging (see <code class="filename">the 'debugging dracut' section</code>), and attach all relevant information from the boot log. This can be obtained by running the command </p><pre class="screen"># dmesg|grep dracut</pre></li><li class="listitem"><p>If you use a dracut configuration file, please include <code class="filename">/etc/dracut.conf</code> and all files in <code class="filename">/etc/dracut.conf.d/*.conf</code></p></li></ul></div></div><div class="section" title="Logical Volume Management related problems"><div class="titlepage"><div><div><h4 class="title"><a id="logical-volume-management-related-problems"></a>Logical Volume Management related problems</h4></div></div></div><p>As well as the information from <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a> include the following information: </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Include physical volume information by running the command: </p><pre class="screen"># lvm pvdisplay</pre></li><li class="listitem"><p>Include volume group information by running the command: </p><pre class="screen"># lvm vgdisplay</pre></li><li class="listitem"><p>Include logical volume information by running the command: </p><pre class="screen"># lvm lvdisplay</pre></li></ul></div></div><div class="section" title="Software RAID related problems"><div class="titlepage"><div><div><h4 class="title"><a id="software-raid-related-problems"></a>Software RAID related problems</h4></div></div></div><p>As well as the information from <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a>, include the following information: </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>If using software RAID disk partitions, please include the output of </p><pre class="screen"># cat /proc/mdstat</pre></li></ul></div></div><div class="section" title="Network root device related problems"><div class="titlepage"><div><div><h4 class="title"><a id="network-root-device-related-problems"></a>Network root device related problems</h4></div></div></div><p>This section details information to include when experiencing problems on a system whose root device is located on a network attached volume (e.g. iSCSI, NFS or NBD). As well as the information from <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a>, include the following information: </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Please include the output of </p><pre class="screen"># /sbin/ifup <em class="replaceable"><code><interfacename></code></em> # ip addr show</pre></li></ul></div></div></div><div class="section" title="Debugging dracut"><div class="titlepage"><div><div><h3 class="title"><a id="debugging-dracut"></a>Debugging dracut</h3></div></div></div><div class="section" title="Configure a serial console"><div class="titlepage"><div><div><h4 class="title"><a id="configure-a-serial-console"></a>Configure a serial console</h4></div></div></div><p>Successfully debugging dracut will require some form of console logging during the system boot. This section documents configuring a serial console connection to record boot messages. </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>First, enable serial console output for both the kernel and the bootloader. </p></li><li class="listitem"><p>Open the file <code class="filename">/etc/grub.conf</code> for editing. Below the line ''timeout=5'', add the following: </p><pre class="screen">serial --unit=0 --speed=9600 terminal --timeout=5 serial console</pre></li><li class="listitem"><p>Also in <code class="filename">/etc/grub.conf</code>, add the following boot arguemnts to the ''kernel'' line: </p><pre class="screen">console=tty0 console=ttyS0,9600</pre></li><li class="listitem"><p>When finished, the <code class="filename">/etc/grub.conf</code> file should look similar to the example below. </p><pre class="screen">default=0 timeout=5 serial --unit=0 --speed=9600 terminal --timeout=5 serial console title Fedora (2.6.29.5-191.fc11.x86_64) root (hd0,0) kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 console=ttyS0,9600 initrd /dracut-2.6.29.5-191.fc11.x86_64.img</pre></li><li class="listitem"><p>More detailed information on how to configure the kernel for console output can be found at <a class="ulink" href="http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL" target="_top">http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL</a>. </p></li></ol></div><div class="note" title="Redirecting non-interactive output" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Redirecting non-interactive output</h3><p>You can redirect all non-interactive output to <code class="filename">/dev/kmsg</code> and the kernel will put it out on the console when it reaches the kernel buffer by doing</p><pre class="screen"># exec >/dev/kmsg 2>&1 </dev/console</pre></div></div><div class="section" title="Using the dracut shell"><div class="titlepage"><div><div><h4 class="title"><a id="using-the-dracut-shell"></a>Using the dracut shell</h4></div></div></div><p>Dracut offers a shell for interactive debugging in the event dracut fails to locate your root filesystem. To enable the shell: </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>Add the boot parameter ''rdshell'' to your bootloader configuration file (e.g. <code class="filename">/etc/grub.conf</code>)</p></li><li class="listitem"><p>Remove the boot arguments ''rhgb'' and ''quiet'' </p><p> A sample <code class="filename">/etc/grub.conf</code> bootloader configuration file is listed below. </p><pre class="screen">default=0 timeout=5 serial --unit=0 --speed=9600 terminal --timeout=5 serial console title Fedora (2.6.29.5-191.fc11.x86_64) root (hd0,0) kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 rdshell initrd /dracut-2.6.29.5-191.fc11.x86_64.img</pre></li><li class="listitem"><p>If system boot fails, you will be dropped into a shell as seen in the example below. </p><pre class="screen">No root device found Dropping to debug shell. sh: can't access tty; job control turned off # </pre></li><li class="listitem"><p>Use this shell prompt to gather the information requested above (see <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a>). </p></li></ol></div></div><div class="section" title="Accessing the root volume from the dracut shell"><div class="titlepage"><div><div><h4 class="title"><a id="accessing-the-root-volume-from-the-dracut-shell"></a>Accessing the root volume from the dracut shell</h4></div></div></div><p>From the dracut debug shell, you can manually perform the task of locating and preparing your root volume for boot. The required steps will depend on how your root volume is configured. Common scenarios include: </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>A block device (e.g. <code class="filename">/dev/sda7</code>) </p></li><li class="listitem"><p>A LVM logical volume (e.g. <code class="filename">/dev/VolGroup00/LogVol00</code>) </p></li><li class="listitem"><p>An encrypted device (e.g. <code class="filename">/dev/mapper/luks-4d5972ea-901c-4584-bd75-1da802417d83</code>) </p></li><li class="listitem"><p>A network attached device (e.g. netroot=iscsi:@192.168.0.4::3260::iqn.2009-02.org.fedoraproject:for.all) </p></li></ul></div><p>The exact method for locating and preparing will vary. However, to continue with a successful boot, the objective is to locate your root volume and create a symlink <code class="filename">/dev/root</code> which points to the file system. For example, the following example demonstrates accessing and booting a root volume that is an encrypted LVM Logical volume. </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>Inspect your partitions using <span class="command"><strong>parted</strong></span></p><pre class="screen"># parted /dev/sda -s p Model: ATA HTS541060G9AT00 (scsi) Disk /dev/sda: 60.0GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 10.8GB 107MB primary ext4 boot 2 10.8GB 55.6GB 44.7GB logical lvm</pre></li><li class="listitem"><p>You recall that your root volume was a LVM logical volume. Scan and activate any logical volumes. </p><pre class="screen"># lvm vgscan # lvm vgchange -ay</pre></li><li class="listitem"><p>You should see any logical volumes now using the command <span class="command"><strong>blkid</strong></span>: </p><pre class="screen"># blkid /dev/sda1: UUID="3de247f3-5de4-4a44-afc5-1fe179750cf7" TYPE="ext4" /dev/sda2: UUID="Ek4dQw-cOtq-5MJu-OGRF-xz5k-O2l8-wdDj0I" TYPE="LVM2_member" /dev/mapper/linux-root: UUID="def0269e-424b-4752-acf3-1077bf96ad2c" TYPE="crypto_LUKS" /dev/mapper/linux-home: UUID="c69127c1-f153-4ea2-b58e-4cbfa9257c5e" TYPE="ext3" /dev/mapper/linux-swap: UUID="47b4d329-975c-4c08-b218-f9c9bf3635f1" TYPE="swap" </pre></li><li class="listitem"><p>From the output above, you recall that your root volume exists on an encrypted block device. Following the guidance disk encryption guidance from the Installation Guide, you unlock your encrypted root volume. </p><pre class="screen"># UUID=$(cryptsetup luksUUID /dev/mapper/linux-root) # cryptsetup luksOpen /dev/mapper/linux-root luks-$UUID Enter passphrase for /dev/mapper/linux-root: Key slot 0 unlocked. </pre></li><li class="listitem"><p>Next, make a symbolic link to the unlocked root volume </p><pre class="screen"># ln -s /dev/mapper/luks-$UUID /dev/root</pre></li><li class="listitem"><p>With the root volume available, you may continue booting the system by exiting the dracut shell </p><pre class="screen"># exit</pre></li></ol></div></div><div class="section" title="Additional dracut boot parameters"><div class="titlepage"><div><div><h4 class="title"><a id="additional-dracut-boot-parameters"></a>Additional dracut boot parameters</h4></div></div></div><p>For more debugging options, see <a class="xref" href="#dracut-kernel-debug" title="Debug">the section called “Debug”</a> in the man page <a class="xref" href="#dracutkernel7" title="dracut"><span class="refentrytitle">dracut</span>(8)</a>.</p></div></div></div></div><div class="appendix" title="Appendix A. Man Pages"><div class="titlepage"><div><div><h2 class="title"><a id="idp3483904"></a>Appendix A. Man Pages</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#dracut.man">dracut</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracut8">dracut</a></span><span class="refpurpose"> — create initial ramdisk images for preloading modules</span></dt></dl></dd><dt><span class="section"><a href="#dracut.conf">dracut.conf</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracutconf5">dracut.conf</a></span><span class="refpurpose"> — configuration file(s) for dracut</span></dt></dl></dd><dt><span class="section"><a href="#dracut.kernel">dracut.kernel</a></span></dt><dd><dl><dt><span class="refentrytitle"><a href="#dracutkernel7">dracut</a></span><span class="refpurpose"> — dracut kernel command line options</span></dt></dl></dd></dl></div><div class="section" title="dracut"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="dracut.man"></a>dracut</h2></div></div></div><div class="refentry" title="dracut"><a id="dracut8"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>dracut — create initial ramdisk images for preloading modules</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">dracut</code> [ <em class="replaceable"><code>OPTION</code></em> ...] [ <em class="replaceable"><code><image></code></em> [ <em class="replaceable"><code><kernel-version></code></em> ] ]<br /></p></div></div><div class="refsect1" title="Description"><a id="idp3496840"></a><h2>Description</h2><p><span class="command"><strong>dracut</strong></span> creates an initial image used by the kernel for preloading the block device modules (such as IDE, SCSI or RAID) which are needed to access the root filesystem.</p><p> For a complete list of kernel command line options see <span class="citerefentry"><span class="refentrytitle">dracut.kernel</span>(7)</span> </p><div class="refsect2" title="Options"><a id="idp3498616"></a><h3>Options</h3><div class="variablelist"><dl><dt><span class="term"> <code class="option">-f</code> , </span><span class="term"> <code class="option">--force</code> </span></dt><dd><p>overwrite existing initramfs file.</p></dd><dt><span class="term"> <code class="option">-m</code> , </span><span class="term"> <code class="option">--modules <em class="replaceable"><code><list of dracut modules></code></em></code> </span></dt><dd><p>specify a space-separated list of dracut modules to call when building the initramfs. Modules are located in <code class="filename">/usr/share/dracut/modules.d</code>. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">-o</code> , </span><span class="term"> <code class="option">--omit <em class="replaceable"><code><list of dracut modules></code></em></code> </span></dt><dd><p>omit a space-separated list of dracut modules. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">-a</code> , </span><span class="term"> <code class="option">--add <em class="replaceable"><code><list of dracut modules></code></em></code> </span></dt><dd><p>add a space-separated list of dracut modules to the default set of modules. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">-d</code> , </span><span class="term"> <code class="option">--drivers <em class="replaceable"><code><list of kernel modules></code></em></code> </span></dt><dd><p>specify a space-separated list of kernel modules to exclusively include in the initramfs. The kernel modules have to be specified without the ".ko" suffix. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">--add-drivers <em class="replaceable"><code><list of kernel modules></code></em></code> </span></dt><dd><p>specify a space-separated list of kernel modules to add to the initramfs. The kernel modules have to be specified without the ".ko" suffix. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">--filesystems <em class="replaceable"><code><list of filesystems></code></em></code> </span></dt><dd><p>specify a space-separated list of kernel filesystem modules to exclusively include in the generic initramfs. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">-k</code> , </span><span class="term"> <code class="option">--kmoddir <em class="replaceable"><code><kernel directory></code></em></code> </span></dt><dd><p>specify the directory, where to look for kernel modules</p></dd><dt><span class="term"> <code class="option"> --fwdir <em class="replaceable"><code><dir>[:<dir>...]</code></em></code> </span></dt><dd><p>specify additional directories, where to look for firmwares. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="option">--kernel-only</code> </span></dt><dd><p>only install kernel drivers and firmware files</p></dd><dt><span class="term"> <code class="option">--no-kernel</code> </span></dt><dd><p>do not install kernel drivers and firmware files</p></dd><dt><span class="term"> <code class="option">--mdadmconf</code> </span></dt><dd><p>include local <code class="filename">/etc/mdadm.conf</code></p></dd><dt><span class="term"> <code class="option">--nomdadmconf</code> </span></dt><dd><p>do not include local <code class="filename">/etc/mdadm.conf</code></p></dd><dt><span class="term"> <code class="option">--strip</code> </span></dt><dd><p>strip binaries in the initramfs (default)</p></dd><dt><span class="term"> <code class="option">--nostrip</code> </span></dt><dd><p>do not strip binaries in the initramfs</p></dd><dt><span class="term"> <code class="option">-h</code> , </span><span class="term"> <code class="option">--help</code> </span></dt><dd><p>display help text and exit.</p></dd><dt><span class="term"> <code class="option">--debug</code> </span></dt><dd><p>output debug information of the build process</p></dd><dt><span class="term"> <code class="option">-v</code> , </span><span class="term"> <code class="option">--verbose</code> </span></dt><dd><p>verbose output during the build process</p></dd><dt><span class="term"> <code class="option">-c</code> , </span><span class="term"> <code class="option">--conf <em class="replaceable"><code><dracut configuration file></code></em></code> </span></dt><dd><p>specify configuration file to use. Default: <code class="filename">/etc/dracut.conf</code></p></dd><dt><span class="term"> <code class="option">--confdir <em class="replaceable"><code><configuration directory></code></em></code> </span></dt><dd><p>specify configuration directory to use. Default: <code class="filename">/etc/dracut.conf.d</code></p></dd><dt><span class="term"> <code class="option">-l</code> , </span><span class="term"> <code class="option">--local</code> </span></dt><dd><p>activates the local mode. dracut will use modules from the current working directory instead of the system-wide installed modules in <code class="filename">/usr/share/dracut/modules.d</code>. This is useful when running dracut from a git checkout.</p></dd><dt><span class="term"> <code class="option">-H</code> , </span><span class="term"> <code class="option">--hostonly</code> </span></dt><dd><p>Host-Only mode: Install only what is needed for booting the local host instead of a generic host. </p><div class="warning" title="Warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>If chrooted to another root other than the real root device, use "--fstab" and provide a valid <code class="filename">/etc/fstab</code>.</p></div></dd><dt><span class="term"> <code class="option">--fstab</code> </span></dt><dd><p>Use <code class="filename">/etc/fstab</code> instead of <code class="filename">/proc/self/mountinfo</code>.</p></dd><dt><span class="term"> <code class="option">-i</code> , </span><span class="term"> <code class="option">--include <em class="replaceable"><code><source directory></code></em> <em class="replaceable"><code><target directory></code></em></code> </span></dt><dd><p>include the files in the source directory into the target directory in the final initramfs.</p></dd><dt><span class="term"> <code class="option">-I</code> , </span><span class="term"> <code class="option">--install <em class="replaceable"><code><file list></code></em></code> </span></dt><dd><p>install the space separated list of files into the initramfs.</p></dd></dl></div></div></div><div class="refsect1" title="Files"><a id="idp3536272"></a><h2>Files</h2><div class="variablelist"><dl><dt><span class="term"> <code class="filename">/var/log/dracut.log</code> </span></dt><dd><p>logfile of initramfs image creation</p></dd><dt><span class="term"> <code class="filename">/tmp/dracut.log</code> </span></dt><dd><p>logfile of initramfs image creation, if <code class="filename">/var/log/dracut.log</code> is not writable</p></dd><dt><span class="term"> <code class="filename">/etc/dracut.conf</code> </span></dt><dd><p>see <span class="citerefentry"><span class="refentrytitle">dracut.conf</span>(5)</span></p></dd><dt><span class="term"> <code class="filename">/etc/dracut.conf.d/*.conf</code> </span></dt><dd><p>see <span class="citerefentry"><span class="refentrytitle">dracut.conf</span>(5)</span></p></dd></dl></div><div class="refsect2" title="Configuration in the Initramfs"><a id="idp3542480"></a><h3>Configuration in the Initramfs</h3><div class="variablelist"><dl><dt><span class="term"> <code class="filename">/conf/conf.d/</code> </span></dt><dd><p>Any files found in <code class="filename">/conf/conf.d/</code> will be sourced in the initramfs to set initial values. Command line options will override these values set in the configuration files.</p></dd><dt><span class="term"> <code class="filename">/etc/cmdline</code> </span></dt><dd><p>Can contain additional command line options.</p></dd></dl></div></div></div><div class="refsect1" title="Availability"><a id="idp3545840"></a><h2>Availability</h2><p>The dracut command is part of the dracut package and is available from <a class="ulink" href="http://sourceforge.net/apps/trac/dracut/wiki" target="_top">http://sourceforge.net/apps/trac/dracut/wiki</a></p></div><div class="refsect1" title="See Also"><a id="idp3546856"></a><h2>See Also</h2><p> <span class="citerefentry"><span class="refentrytitle">dracut.kernel</span>(7)</span> <span class="citerefentry"><span class="refentrytitle">dracut.conf</span>(5)</span> </p></div></div></div><div class="section" title="dracut.conf"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="dracut.conf"></a>dracut.conf</h2></div></div></div><div class="refentry" title="dracut.conf"><a id="dracutconf5"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>dracut.conf — configuration file(s) for dracut</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">/etc/dracut.conf</code> <em class="replaceable"><code>/etc/dracut.conf.d/*.conf</code></em> <br /></p></div></div><div class="refsect1" title="Description"><a id="idp3554008"></a><h2>Description</h2><p><code class="filename">dracut.conf</code> is loaded during the initialisation phase of dracut. Command line parameter will overwrite any values set here. <span class="emphasis"><em><code class="filename">dracut.conf.d/*.conf</code> files are read in alphanumerical order and will</em></span> overwrite parameters set in <code class="filename">/etc/dracut.conf</code>. Each line specifies an attribute and a value. A '#' indicates the beginning of a comment; following characters, up to the end of the line are not interpreted.</p><div class="variablelist"><dl><dt><span class="term"> <code class="envar">dracutmodules+=" <em class="replaceable"><code><dracut modules></code></em> "</code> </span></dt><dd><p>Specify a space-separated list of dracut modules to call when building the initramfs. Modules are located in <code class="filename">/usr/share/dracut/modules.d</code>.</p></dd><dt><span class="term"> <code class="envar">omit_dracutmodules+=" <em class="replaceable"><code><dracut modules></code></em> "</code> </span></dt><dd><p>Omit a space-separated list of dracut modules.</p></dd><dt><span class="term"> <code class="envar">add_dracutmodules+=" <em class="replaceable"><code><dracut modules></code></em> "</code> </span></dt><dd><p>Add a space-separated list of dracut modules.</p></dd><dt><span class="term"> <code class="envar">drivers+=" <em class="replaceable"><code><kernel modules></code></em> "</code> </span></dt><dd><p>Specify a space-separated list of kernel modules to exclusively include in the initramfs. The kernel modules have to be specified without the ".ko" suffix.</p></dd><dt><span class="term"> <code class="envar">add_drivers+=" <em class="replaceable"><code><kernel modules></code></em> "</code> </span></dt><dd><p>Specify a space-separated list of kernel modules to add to the initramfs. The kernel modules have to be specified without the ".ko" suffix.</p></dd><dt><span class="term"> <code class="envar">filesystems+=" <em class="replaceable"><code><filesystem names></code></em> "</code> </span></dt><dd><p>Specify a space-separated list of kernel filesystem modules to exclusively include in the generic initramfs.</p></dd><dt><span class="term"> <code class="envar">drivers_dir="<em class="replaceable"><code><kernel modules directory></code></em>"</code> </span></dt><dd><p>Specify the directory, where to look for kernel modules</p></dd><dt><span class="term"> <code class="envar">fw_dir+=" :<em class="replaceable"><code><dir></code></em>[:<em class="replaceable"><code><dir></code></em> ...] "</code> </span></dt><dd><p>Specify additional directories, where to look for firmwares, separated by <code class="constant">:</code></p></dd><dt><span class="term"> <code class="envar">do_strip="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Strip binaries in the initramfs (default=yes)</p></dd><dt><span class="term"> <code class="envar">hostonly="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Host-Only mode: Install only what is needed for booting the local host instead of a generic host. </p><div class="warning" title="Warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>If chrooted to another root other than the real root device, use <code class="option">--fstab</code> and provide a valid <code class="filename">/etc/fstab</code>.</p></div><p> </p></dd><dt><span class="term"> <code class="envar">use_fstab="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Use <code class="filename">/etc/fstab</code> instead of <code class="filename">/proc/self/mountinfo</code>.</p></dd><dt><span class="term"> <code class="envar">mdadmconf="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Include local <code class="filename">/etc/mdadm.conf</code> (default=yes)</p></dd><dt><span class="term"> <code class="envar">lvmconf="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Include local <code class="filename">/etc/lvm/lvm.conf</code> (default=yes)</p></dd><dt><span class="term"> <code class="envar">kernel_only="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Only install kernel drivers and firmware files. (default=no)</p></dd><dt><span class="term"> <code class="envar">no_kernel="<em class="replaceable"><code>{yes|no}</code></em>"</code> </span></dt><dd><p>Do not install kernel drivers and firmware files (default=no)</p></dd></dl></div></div><div class="refsect1" title="Files"><a id="idp3578448"></a><h2>Files</h2><div class="variablelist"><dl><dt><span class="term"> <code class="filename">/etc/dracut/conf.d/</code> </span></dt><dd><p>Any <code class="filename">/etc/dracut/conf.d/*.conf</code> file can overwrite the values in <code class="filename">/etc/dracut.conf</code>. The configuration files are read in alphanumerical order.</p></dd></dl></div></div><div class="refsect1" title="See Also"><a id="idp3580840"></a><h2>See Also</h2><p><span class="citerefentry"><span class="refentrytitle">dracut</span>(8)</span> <span class="citerefentry"><span class="refentrytitle">dracut.kernel</span>(7)</span> </p></div></div></div><div class="section" title="dracut.kernel"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="dracut.kernel"></a>dracut.kernel</h2></div></div></div><div class="refentry" title="dracut"><a id="dracutkernel7"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>dracut.kernel — dracut kernel command line options</p></div><div class="refsect1" title="Description"><a id="idp3586608"></a><h2>Description</h2><p>The root filesystem used by the kernel is specified in the boot configuration file, as always. The traditional <span class="emphasis"><em>root=/dev/hda1</em></span> style device specification is allowed. If a label is used, as in <span class="emphasis"><em>root=LABEL=rootPart</em></span> the initramfs will search all available devices for an ext2 or ext3 filesystem with the appropriate label, and mount that device as the root filesystem. <span class="emphasis"><em>root=UUID=uuidnumber</em></span> will mount the partition with that UUID as the root filesystem.</p><div class="refsect2" title="Standard"><a id="idp3588504"></a><h3>Standard</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">init=<em class="replaceable"><code><path to real init></code></em></code> </span></dt><dd><p> </p></dd><dt><span class="term"> <code class="envar">root=<em class="replaceable"><code><path to blockdevice></code></em></code> </span></dt><dd><p>specify blockdevice to use as root filesystem. e.g.: </p><pre class="programlisting">root=/dev/sda1 root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1 </pre></dd><dt><span class="term"> <code class="envar">rootfstype=<em class="replaceable"><code><filesystem type></code></em></code> </span></dt><dd><p>"auto" if not specified, e.g.: </p><pre class="programlisting">rootfstype=ext3</pre></dd><dt><span class="term"> <code class="envar">rootflags=<em class="replaceable"><code><mount options></code></em></code> </span></dt><dd><p>specify additional mount options for the root filesystem. If not set, <code class="filename">/etc/fstab</code> of the real root will be parsed for special mount options and mounted accordingly.</p></dd></dl></div></div><div class="refsect2" title="Misc"><a id="idp3594832"></a><h3>Misc</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rdblacklist=<em class="replaceable"><code><drivername>[<span class="optional">,<drivername>,...</span>]</code></em></code> </span></dt><dd><p>do not load kernel module <drivername> This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="envar">rdloaddriver=<em class="replaceable"><code><drivername>[<span class="optional">,<drivername>,...</span>]</code></em></code> </span></dt><dd><p>force loading kernel module <drivername> This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="envar">rdrdinsmodpost=<em class="replaceable"><code><drivername>[<span class="optional">,<drivername>,...</span>]</code></em></code> </span></dt><dd><p>force loading kernel module <drivername> after all automatic loading modules have been loaded. This parameter can be specified multiple times.</p></dd></dl></div></div><div class="refsect2" title="Debug"><a id="dracut-kernel-debug"></a><h3>Debug</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rdinfo</code> </span></dt><dd><p>print informational output though "quiet" is set</p></dd><dt><span class="term"> <code class="envar">rdshell</code> </span></dt><dd><p>allow dropping to a shell, if root mounting fails</p></dd><dt><span class="term"> <code class="envar">rdinitdebug</code> </span></dt><dd><p>set -x for the dracut shell and logs to dmesg, console and <code class="filename">/init.log</code></p></dd><dt><span class="term"> <code class="envar">rdbreak</code> </span></dt><dd><p>drop to a shell at the end</p></dd><dt><span class="term"> <code class="envar">rdbreak=</code> <em class="replaceable"><code>{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot}</code></em> </span></dt><dd><p>drop to a shell on defined breakpoint</p></dd><dt><span class="term"> <code class="envar">rdudevinfo</code> </span></dt><dd><p>set udev to loglevel info</p></dd><dt><span class="term"> <code class="envar">rdudevdebug</code> </span></dt><dd><p>set udev to loglevel debug</p></dd></dl></div></div><div class="refsect2" title="I18N"><a id="idp3608136"></a><h3>I18N</h3><p>e.g.</p><pre class="programlisting">LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=de-latin1-nodeadkeys</pre><div class="variablelist"><dl><dt><span class="term"> <code class="envar">KEYBOARDTYPE=</code> <em class="replaceable"><code>sun|pc</code></em> </span></dt><dd><p>will be written to /etc/sysconfig/keyboard in the initramfs</p></dd><dt><span class="term"> <code class="envar">KEYTABLE=</code> <em class="replaceable"><code><keytable filename></code></em> </span></dt><dd><p>will be written to /etc/sysconfig/keyboard in the initramfs</p></dd><dt><span class="term"> <code class="envar">SYSFONT=</code> <em class="replaceable"><code><console font></code></em> </span></dt><dd><p>will be written to /etc/sysconfig/i18n in the initramfs</p></dd><dt><span class="term"> <code class="envar">SYSFONTACM=</code> <em class="replaceable"><code><console font map></code></em> </span></dt><dd><p>will be written to /etc/sysconfig/i18n in the initramfs</p></dd><dt><span class="term"> <code class="envar">UNIMAP=</code> <em class="replaceable"><code><unicode font map></code></em> </span></dt><dd><p>will be written to /etc/sysconfig/i18n in the initramfs</p></dd><dt><span class="term"> <code class="envar">LANG=</code> <em class="replaceable"><code><locale></code></em> </span></dt><dd><p>will be written to /etc/sysconfig/i18n in the initramfs</p></dd></dl></div></div><div class="refsect2" title="LVM"><a id="idp3616656"></a><h3>LVM</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rd_NO_LVM</code> </span></dt><dd><p>disable LVM detection</p></dd><dt><span class="term"> <code class="envar">rd_NO_LVM.vg=<em class="replaceable"><code><volume group name></code></em></code> </span></dt><dd><p>only activate the volume groups with the given name <code class="envar">rd_NO_LVM.vg</code> can be specified multiple times on the kernel command line.</p></dd><dt><span class="term"> <code class="envar">rd_LVM_LV=<em class="replaceable"><code><logical volume name></code></em></code> </span></dt><dd><p>only activate the logical volumes with the given name <code class="envar">rd_LVM_LV</code> can be specified multiple times on the kernel command line.</p></dd><dt><span class="term"> <code class="envar">rd_NO_LVMCONF</code> </span></dt><dd><p>remove any <code class="filename">/etc/lvm/lvm.conf</code>, which may exist in the initramfs</p></dd></dl></div></div><div class="refsect2" title="crypto LUKS"><a id="idp3622432"></a><h3>crypto LUKS</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rd_NO_LUKS</code> </span></dt><dd><p>disable crypto LUKS detection</p></dd><dt><span class="term"> <code class="envar">rd_LUKS_UUID=<em class="replaceable"><code><luks uuid></code></em></code> </span></dt><dd><p>only activate the LUKS partitions with the given UUID Any "luks-" of the LUKS UUID is removed before comparing to <em class="replaceable"><code><luks uuid></code></em>. The comparisons also matches, if <em class="replaceable"><code><luks uuid></code></em> is only the beginning of the LUKS UUID, so you don't have to specify the full UUID. This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="envar">rd_NO_CRYPTTAB</code> </span></dt><dd><p>do not check, if LUKS partition is in <code class="filename">/etc/crypttab</code></p></dd></dl></div></div><div class="refsect2" title="MD"><a id="idp3627328"></a><h3>MD</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rd_NO_MD</code> </span></dt><dd><p>disable MD RAID detection</p></dd><dt><span class="term"> <code class="envar">rd_NO_MDIMSM</code> </span></dt><dd><p>disable MD RAID for imsm/isw raids, use DM RAID instead</p></dd><dt><span class="term"> <code class="envar">rd_NO_MDADMCONF</code> </span></dt><dd><p>ignore mdadm.conf included in initramfs</p></dd><dt><span class="term"> <code class="envar">rd_MD_UUID=<em class="replaceable"><code><md raid uuid></code></em></code> </span></dt><dd><p>only activate the raid sets with the given UUID. This parameter can be specified multiple times.</p></dd></dl></div></div><div class="refsect2" title="DM RAID"><a id="idp3632096"></a><h3>DM RAID</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">rd_NO_DM</code>=0</span></dt><dd><p>disable DM RAID detection</p></dd><dt><span class="term"> <code class="envar">rd_DM_UUID=<em class="replaceable"><code><dm raid uuid></code></em></code> </span></dt><dd><p>only activate the raid sets with the given UUID. This parameter can be specified multiple times.</p></dd></dl></div></div><div class="refsect2" title="Network"><a id="idp3634768"></a><h3>Network</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">ip=</code> <em class="replaceable"><code>{dhcp|on|any|dhcp6|auto6}</code></em> </span></dt><dd><p>dhcp|on|any: get ip from dhcp server from all interfaces. If root=dhcp, loop sequentially through all interfaces (eth0, eth1, ...) and use the first with a valid DHCP root-path.</p><p><code class="constant">auto6</code>: IPv6 autoconfiguration</p><p><code class="constant">dhcp6</code>: IPv6 DHCP</p></dd><dt><span class="term"><code class="envar">ip=</code><em class="replaceable"><code><interface></code></em>:<em class="replaceable"><code>{dhcp|on|any|dhcp6|auto6}</code></em></span></dt><dd><p>dhcp|on|any|dhcp6: get ip from dhcp server on a specific interface auto6: do IPv6 autoconfiguration This parameter can be specified multiple times.</p></dd><dt><span class="term"><code class="envar">ip=</code><em class="replaceable"><code><client-IP></code></em>:[<span class="optional"> <em class="replaceable"><code><server-id></code></em> </span>]:<em class="replaceable"><code><gateway-IP></code></em>:<em class="replaceable"><code><netmask></code></em>:<em class="replaceable"><code><client_hostname></code></em>:<em class="replaceable"><code><interface></code></em>:<em class="replaceable"><code>{none|off}</code></em></span></dt><dd><p>explicit network configuration. If you want do define a IPv6 address, put it in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple times.</p></dd><dt><span class="term"><code class="envar">ifname=</code><em class="replaceable"><code><interface></code></em>:<em class="replaceable"><code><MAC></code></em></span></dt><dd><p>Assign network device name <interface> (ie eth0) to the NIC with MAC <MAC>. <em><span class="remark">Note: If you use this option you <span class="emphasis"><em>must</em></span> specify an ifname= argument for all interfaces used in ip= or fcoe= arguments.</span></em> This parameter can be specified multiple times.</p></dd><dt><span class="term"> <code class="envar">bootdev=</code> <em class="replaceable"><code><interface></code></em> </span></dt><dd><p>specify network interface to use routing and netroot information from. Required if multiple ip= lines are used.</p></dd><dt><span class="term"> <code class="envar">nameserver=</code> <em class="replaceable"><code><IP></code></em> [<span class="optional"><code class="envar">nameserver</code>=<em class="replaceable"><code><IP></code></em> ...</span>] </span></dt><dd><p>specify nameserver(s) to use</p></dd><dt><span class="term"> <code class="envar">biosdevname=</code> <em class="replaceable"><code>{0|1}</code></em> </span></dt><dd><p>turn on/off biosdevname network interface renaming</p></dd></dl></div></div><div class="refsect2" title="NFS"><a id="idp3647376"></a><h3>NFS</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">root=</code> [<span class="optional"><em class="replaceable"><code><server-ip></code></em>:</span>] <em class="replaceable"><code><root-dir></code></em> [<span class="optional">:<em class="replaceable"><code><nfs-options></code></em></span>] </span></dt><dd><p>mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use dhcp next_server. if server-ip is an IPv6 address it has to be put in brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix ":" or "," and are seperated by ",".</p></dd><dt><span class="term"><code class="envar">root=</code><code class="constant">nfs</code>:[<span class="optional"><em class="replaceable"><code><server-ip></code></em>:</span>]<em class="replaceable"><code><root-dir></code></em>[<span class="optional">:<em class="replaceable"><code><nfs-options></code></em></span>], </span><span class="term"><code class="envar">root=</code>nfs4:[<span class="optional"><em class="replaceable"><code><server-ip></code></em>:</span>]<em class="replaceable"><code><root-dir></code></em>[<span class="optional">:<em class="replaceable"><code><nfs-options></code></em></span>], </span><span class="term"> <code class="envar">root=</code> <em class="replaceable"><code>{dhcp|dhcp6}</code></em> </span></dt><dd><p>root=dhcp alone directs initrd to look at the DHCP root-path where NFS options can be specified. root-path=<server-ip>:<root-dir>[,<nfs-options>] root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>] root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]</p></dd><dt><span class="term"> <code class="envar">root=</code> <code class="filename">/dev/nfs</code> <code class="envar"> nfsroot=</code> [<span class="optional"><em class="replaceable"><code><server-ip></code></em>:</span>] <em class="replaceable"><code><root-dir></code></em> [<span class="optional">:<em class="replaceable"><code><nfs-options></code></em></span>] </span></dt><dd><p><span class="emphasis"><em>Deprecated!</em></span> kernel Documentation<code class="filename">/filesystems/nfsroot.txt</code> defines this method. This is supported by dracut, but not recommended.</p></dd><dt><span class="term"> <code class="envar">rd_NFS_DOMAIN=</code> <em class="replaceable"><code><NFSv4 domain name></code></em> </span></dt><dd><p>Set the NFSv4 domain name. Will overwrite the settings in <code class="filename">/etc/idmap.conf</code>.</p></dd></dl></div></div><div class="refsect2" title="iSCSI"><a id="idp3658544"></a><h3>iSCSI</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">root=</code><code class="constant">iscsi</code>:[<span class="optional"><em class="replaceable"><code><username></code></em>:<em class="replaceable"><code><password></code></em>[<span class="optional">:<em class="replaceable"><code><reverse></code></em>:<em class="replaceable"><code><password></code></em></span>]@</span>][<span class="optional"> <em class="replaceable"><code><servername></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><protocol></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><port></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><LUN></code></em> </span>]:<em class="replaceable"><code><targetname></code></em></span></dt><dd><p>protocol defaults to "6", LUN defaults to "0".</p><p>If the "servername" field is provided by <acronym class="acronym">BOOTP</acronym> or <acronym class="acronym">DHCP</acronym>, then that field is used in conjunction with other associated fields to contact the boot server in the Boot stage. However, if the "servername" field is not provided, then the "targetname" field is then used in the Discovery Service stage in conjunction with other associated fields.</p><p>See <a class="ulink" href="http://tools.ietf.org/html/rfc4173#section-5" target="_top">http://tools.ietf.org/html/rfc4173</a>.</p><p>e.g.:</p><pre class="programlisting">root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0 </pre><p>If servername is an IPv6 address, it has to be put in brackets. e.g.: </p><pre class="programlisting">root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0 </pre></dd><dt><span class="term"><code class="envar">root=</code><em class="replaceable"><code>???</code></em><code class="envar"> netroot=</code><code class="constant">iscsi</code>:[<span class="optional"><em class="replaceable"><code><username></code></em>:<em class="replaceable"><code><password></code></em>[<span class="optional">:<em class="replaceable"><code><reverse></code></em>:<em class="replaceable"><code><password></code></em></span>]@</span>][<span class="optional"> <em class="replaceable"><code><servername></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><protocol></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><port></code></em> </span>]:[<span class="optional"> <em class="replaceable"><code><LUN></code></em> </span>]:<em class="replaceable"><code><targetname></code></em> ...</span></dt><dd><p>multiple netroot options allow setting up multiple iscsi disks. e.g.: </p><pre class="programlisting">root=UUID=12424547 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1 </pre><p>If servername is an IPv6 address, it has to be put in brackets. e.g.: </p><pre class="programlisting">netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0</pre></dd><dt><span class="term"> <code class="envar">root=<em class="replaceable"><code>???</code></em></code> <code class="envar">iscsi_initiator=<em class="replaceable"><code><initiator> </code></em></code> <code class="envar">iscsi_target_name=<em class="replaceable"><code><target name> </code></em></code> <code class="envar">iscsi_target_ip=<em class="replaceable"><code><target ip> </code></em></code> <code class="envar">iscsi_target_port=<em class="replaceable"><code><target port> </code></em></code> <code class="envar">iscsi_target_group=<em class="replaceable"><code><target group> </code></em></code> <code class="envar">iscsi_username=<em class="replaceable"><code><username> </code></em></code> <code class="envar">iscsi_password=<em class="replaceable"><code><password> </code></em></code> <code class="envar">iscsi_in_username=<em class="replaceable"><code><in username> </code></em></code> <code class="envar">iscsi_in_password=<em class="replaceable"><code><in password> </code></em></code> </span></dt><dd><p>manually specify all iscsistart parameter (see <strong class="userinput"><code>iscsistart --help</code></strong>)</p></dd><dt><span class="term"> <code class="envar">root=</code> <em class="replaceable"><code>??? </code></em> <code class="envar">netroot=iscsi</code> <code class="envar">iscsi_firmware</code> </span></dt><dd><p>will read the iscsi parameter from the BIOS firmware</p></dd></dl></div></div><div class="refsect2" title="FCoE"><a id="idp3676848"></a><h3>FCoE</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">netroot=</code><code class="constant">fcoe</code>:<em class="replaceable"><code><interface|MAC></code></em>:<em class="replaceable"><code>{dcb|nodcb}</code></em></span></dt><dd><p>Try to connect to a FCoE SAN through the NIC specified by <em class="replaceable"><code><interface></code></em> or <em class="replaceable"><code><MAC></code></em>, for the second argument, currently only nodcb is supported. <em><span class="remark">Note: letters in the MAC-address must be lowercase!</span></em></p></dd></dl></div></div><div class="refsect2" title="NBD"><a id="idp3679512"></a><h3>NBD</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">root=</code><code class="constant">nbd</code>:<em class="replaceable"><code><server></code></em>:<em class="replaceable"><code><port></code></em>[<span class="optional">:<em class="replaceable"><code><fstype></code></em></span>][<span class="optional">:<em class="replaceable"><code><mountopts></code></em></span>]</span></dt><dd><p>mount nbd share from <server></p></dd><dt><span class="term"> <code class="envar">root=dhcp</code> </span></dt><dd><p>with dhcp root-path=nbd:<server>:<port>[:<fstype>][:<mountopts>] root=dhcp alone directs initrd to look at the DHCP root-path where NBD options can be specified. This syntax is only usable in cases where you are directly mounting the volume as the rootfs.</p></dd></dl></div></div><div class="refsect2" title="DASD"><a id="idp3683608"></a><h3>DASD</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">rd_DASD_MOD=</code>....</span></dt><dd><p>same syntax as the kernel module parameter (s390 only)</p></dd><dt><span class="term"> <code class="envar">rd_DASD=</code> <em class="replaceable"><code><dasd_adaptor device bus ID></code></em> [<span class="optional">,readonly=<em class="replaceable"><code>X</code></em></span>] [<span class="optional">,use_diag=<em class="replaceable"><code>X</code></em></span>] [<span class="optional">,erplog=<em class="replaceable"><code>X</code></em></span>] </span></dt><dd><p>activate DASD device with the given adaptor device bus ID and setting the sysfs attributes to the specified values This parameter can be specified multiple times.</p></dd></dl></div></div><div class="refsect2" title="ZFCP"><a id="idp3687496"></a><h3>ZFCP</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">rd_ZFCP=</code><em class="replaceable"><code><zfcp adaptor device bus ID></code></em>,<em class="replaceable"><code><WWPN></code></em>,<em class="replaceable"><code><FCPLUN></code></em></span></dt><dd><p>rd_ZFCP can be specified multiple times on the kernel command line. e.g.: </p><pre class="programlisting">rd_ZFCP=0.0.4000,0x5005076300C213e9,0x5022000000000000</pre></dd><dt><span class="term"> <code class="envar">rd_NO_ZFCPCONF</code> </span></dt><dd><p>ignore zfcp.conf included in the initramfs</p></dd></dl></div></div><div class="refsect2" title="ZNET"><a id="idp3690880"></a><h3>ZNET</h3><div class="variablelist"><dl><dt><span class="term"><code class="envar">rd_ZNET=</code><em class="replaceable"><code><nettype></code></em>,<em class="replaceable"><code><subchannels></code></em>,<em class="replaceable"><code><options></code></em></span></dt><dd><p>rd_ZNET can be specified multiple times on the kernel command line. e.g.: </p><pre class="programlisting">rd_ZNET=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo rd_ZNET=ctc,0.0.0600,0.0.0601,0.0.0602,protocol=bar</pre></dd></dl></div></div><div class="refsect2" title="Plymouth Boot Splash"><a id="idp3693264"></a><h3>Plymouth Boot Splash</h3><div class="variablelist"><dl><dt><span class="term"> <code class="envar">rd_NO_PLYMOUTH</code> </span></dt><dd><p>disable plymouth. This will not work with encrypted partitions.</p></dd></dl></div></div></div><div class="refsect1" title="Configuration in the Initramfs"><a id="idp3694936"></a><h2>Configuration in the Initramfs</h2><div class="variablelist"><dl><dt><span class="term"> <code class="filename">/conf/conf.d/</code> </span></dt><dd><p>Any files found in <code class="filename">/conf/conf.d/</code> will be sourced in the initramfs to set initial values. Command line options will override these values set in the configuration files.</p></dd><dt><span class="term"> <code class="filename">/etc/cmdline</code> </span></dt><dd><p>Can contain additional command line options.</p></dd></dl></div></div><div class="refsect1" title="See Also"><a id="idp3698232"></a><h2>See Also</h2><p> <span class="citerefentry"><span class="refentrytitle">dracut</span>(8)</span> <span class="citerefentry"><span class="refentrytitle">dracut.conf</span>(5)</span> </p></div></div></div></div></div></body></html>
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