GENKERNEL(8) ============ :man source: genkernel {genkernelversion} :man manual: genkernel {genkernelversion} NAME ---- genkernel - the Gentoo Linux automatic kernel compiler. SYNOPSIS -------- *genkernel* [options...] action INTRODUCTION ------------ Genkernel is designed to allow users who are not previously used to compiling a kernel to use a similar setup to that one that is used on the Gentoo LiveCDs which auto-detects your hardware. Some users may also be interested in using genkernel for hardware which requires initialization and a working kernel before it can be booted because genkernel also automatically compiles your kernel modules, allowing hardware which needs to be loaded with module parameters to be used. USAGE ----- All that is needed to run genkernel is just `genkernel` with an action and any flags you might need: ------------------------------------------ # genkernel --menuconfig --no-clean --no-install all ------------------------------------------ This would produce a kernel, asking you what how to configure it to your desire, leaving alone any existing compiled object files, but not installing anything. ACTIONS ------- An action tells genkernel what you want it to do - the following actions are supported: *all*:: Build all steps - the kernel, modules, and the ramdisk. *bzImage*:: Build only the kernel. *initramfs*:: Build only the ramdisk/initramfs. *kernel*:: Build only the kernel and the modules. *ramdisk*:: Build only the ramdisk/initramfs. OPTIONS ------- Genkernel supports the following options which alter its behaviour. Certain options have *--no-* variants which do the opposite thing. You can specify your options in any order. CONFIGURATION OPTIONS ~~~~~~~~~~~~~~~~~~~~~ *--config*=:: Genkernel configuration file to use. DEBUGGING OPTIONS ~~~~~~~~~~~~~~~~~ *--loglevel*=<0-5>:: This controls the out verbosity level of genkernel output - if this is set to 0, minimal debugging is done; if this is set to 5 as much output as possible is given. *--logfile*=:: This outputs debugging data to the file . By default this is '/var/log/genkernel.log'. *--*[*no-*]*color*:: Turns on, or off, output in color using escape sequences. *--*[*no-*]*cleanup*:: Turns on or off the full post-run cleanup for debug purposes. KERNEL CONFIGURATION ~~~~~~~~~~~~~~~~~~~~ *--*[*no-*]*menuconfig*:: Runs, or does not run "make menuconfig" after running "make oldconfig". *--*[*no-*]*nconfig*:: Runs, or does not run "make nconfig" after running "make oldconfig". *--*[*no-*]*gconfig*:: Runs, or does not run "make gconfig" after "make oldconfig". *--*[*no-*]*xconfig*:: Runs, or does not run "make xconfig" after "make oldconfig". *--*[*no-*]*save-config*:: Saves, or does not save the kernel configuration to '/etc/kernels' if the kernel is successfully compiled. *--*[*no-*]*bcache*:: Adds, or skip adding block layer cache (bcache) support to kernel configuration. *--*[*no-*]*hyperv*:: Adds, or skip adding Microsoft Hyper-V support to kernel configuration. *--microcode*[=]:: Adds early microcode loading support for all, only AMD or Intel processors to kernel configuration. *--no-microcode*:: Do not add early microcode loading support to kernel configuration. *--*[*no-*]*virtio*:: Adds, or skip adding VirtIO support to kernel configuration. *--kernel-append-localversion*=<...>:: Appends value to genkernel's *KERNEL_LOCALVERSION* option (see below). The idea is to use this option to allow to easily build a new revision with own kernel binary, initramfs and modules directory without losing default *KERNEL_LOCALVERSION* value. *--kernel-localversion*=<...>:: Set kernel option *LOCALVERSION*. Use special value *UNSET* to unset any already set *LOCALVERSION*. The following placeholders are available: + [horizontal] *%%ARCH%%*::: Will be replaced with genkernel arch value, for example 'x86_64'. + *LOCALVERSION* is only allowed to contain characters like 'a-z' or 'A-Z', '0-9', '_', '.' and '-'. + By default, *LOCALVERSION* will be set to '-%%ARCH%%'. KERNEL COMPILATION ~~~~~~~~~~~~~~~~~~ *--*[*no-*]*clean*:: Runs, or does not run, "make clean" before compilation - this erases any compiled object files in the kernel source tree but does not have an impact on the kernel configuration. Specifying *--no-clean* implies *--no-mrproper*. *--*[*no-*]*mrproper*:: Runs, or does not run, "make mrproper" before compilation - this erases both any compiled object files in the kernel source tree as well as the kernel configuration. *--*[*no-*]*install*:: Installs, or does not install the kernel to '/boot' after building. The default is *--install*. If MOUNTBOOT is set in '/etc/genkernel.conf' then '/boot' will be automatically mounted if it is not already mounted before the ramdisk and kernel images are copied over. *--*[*no-*]*symlink*:: Manages, or does not manage, symlinks in '/boot' like the manual kernel "make install" process does. A 'kernel' (or, depending on options, 'kernelz') symlink will link to the most recently built kernel image and a 'kernel.old' (or 'kernelz.old') symlink will link to the second most recently built image, if one exists. Similar symlinks (with and without '.old' suffix) are managed for initramfs and System.map. The corresponding work products (i.e., the actual kernel and initramfs images, and System.map) are also managed accordingly. + The symlink name can be controlled via *--kernel-symlink-name* and/or *--initramfs-symlink-name* option. NOTE: Specifying *--symlink* does nothing unless *--install* is also specified. *--*[*no-*]*oldconfig*:: Runs, or does not run, "make oldconfig" before compilation. Specifying *--oldconfig* implies *--no-clean*. *--*[*no-*]*splash*:: Installs, or not, framebuffer splash support into initramfs. *--*[*no-*]*ramdisk-modules*:: Copies or does not copy configured modules to the ramdisk. *--*[*no-*]*all-ramdisk-modules*:: Copies or does not copy all kernel modules to the initrd. *--*[*no-*]*module-rebuild*:: Runs, or does not run "emerge --ignore-default-opts --buildpkg=n --usepkg=n --quiet-build=y @module-rebuild" to build out-of-tree modules when possible, i.e. when non-static kernel and modules will be built, installed, *--kernel-modules-prefix* is not set. NOTE: Command can be customized using '--module-rebuild-cmd' command-line argument or 'MODULEREBUILD_CMD' in '/etc/genkernel.conf'. *--module-rebuild-cmd*=<...>:: Overwrite default *--module-rebuild* command. *--callback*=<...>:: Run the specified arguments in the current environment after the kernel and modules have been compiled. *--*[*no-*]*static*:: Builds, or does not build a monolithic kernel without any modules on any initial ramdisks. KERNEL LOCATIONS ~~~~~~~~~~~~~~~~ *--kerneldir*=:: This specifies the location of the kernel sources; the default is '/usr/src/linux'. *--kernel-config*=:: This specifies a kernel configuration file to use for compilation; by default genkernel uses the config from the previous build of the same kernel version or a default kernel config if there isn't a previous config. Use the special value 'default' to force usage of default kernel config. *--kernel-modules-prefix*=:: Prefix to kernel module destination, modules will be installed in '/lib/modules'. LOW-LEVEL COMPILATION OPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *--cross-compile*=:: Target triple (i.e. aarch64-linux-gnu) to build for. Only needed when the system running genkernel has a different architecture like the system which should boot the created kernel/initramfs. *--kernel-cross-compile*=:: Target triple (i.e. aarch64-linux-gnu) to build kernel for. *--kernel-ar*=:: Archiver to use for the kernel compilation. *--kernel-as*=:: Assembler to use for the kernel compilation. *--kernel-cc*=:: Compiler to use for the kernel compilation (e.g. distcc). *--kernel-ld*=:: Linker to use for the kernel compilation. *--kernel-make*=:: GNU Make to use for the kernel compilation. *--kernel-nm*=:: NM utility to use for the kernel compilation. *--kernel-objcopy*=:: Objcopy utility to use for the kernel compilation. *--kernel-objdump*=:: Objdump utility to use for the kernel compilation. *--kernel-ranlib*=:: Ranlib utility to use for the kernel compilation. *--kernel-readelf*=:: Readelf utility to use for the kernel compilation. *--kernel-strip*=:: Strip utility to use for the kernel compilation. *--kernel-target*=:: Override default make target (bzImage), note that values like *--kernel-target=* are also valid (useful for Xen based kernel sources). *--kernel-binary*=:: Override default kernel binary path (arch/foo/boot/bar). *--kernel-outputdir*=:: Save output files outside the source tree. This should be used rather than KBUILD_OUTPUT when you wish to place kernel objects outside of the source tree (eg because cannot write to that directory as the user genkernel is running as). *--utils-ar*=:: Archiver to use for utilities. *--utils-as*=:: Assembler to use for utilities. *--utils-cflags*=:: C compiler flags used to compile utilities. *--utils-cc*=:: C Compiler to use for utilities. *--utils-cxx*=:: C++ Compiler to use for utilities. *--utils-ld*=:: Linker to use for utilities. *--utils-make*=:: GNU Make to use for utilities. *--utils-nm*=:: NM utility to use for utilities. *--utils-objcopy*=:: Objcopy utility to use for utilities. *--utils-objdump*=:: Objdump utility to use for utilities. *--utils-ranlib*=:: Ranlib utility to use for utilities. *--utils-readelf*=:: Readelf utility to use for utilities. *--utils-strip*=:: Strip utility to use for utilities. *--makeopts*=:: GNU Make options such as -j2, etc. *--*[*no-*]*mountboot*:: Mount, or not, BOOTDIR automatically if mountable. *--bootdir*=:: Set the location of the boot-directory, default is '/boot'. *--modprobedir*=:: Set the location of the modprobe.d-directory, default is '/etc/modprobe.d'. *--*[*no-*]*nice*[=]:: Runs the kernel make at the default niceness (reduction in priority) of 10, or in the case of *--no-nice*, runs the kernel make at normal priority. INITIALIZATION ~~~~~~~~~~~~~~ *--splash*=:: Enable framebuffer splash using . *--splash-res*=:: Select gensplash resolutions to include. *--*[*no-*]*splash*=:: If the extra argument is specified, splash is forced using rather than the default theme specified in your splash configuration. If *--no-splash* is specified, then splash is disabled. *--*[*no-*]*plymouth*:: Includes or excludes Plymouth from the initramfs. If "splash" is passed at boot, Plymouth will be activated. *--plymouth-theme*=:: Embeds the given Plymouth theme into the initramfs. *--do-keymap-auto*:: Force keymap selection at boot. *--*[*no-*]*keymap*:: Enables or disables keymap selection at boot. *--*[*no-*]*lvm*:: Includes or excludes LVM support. When enabled, this will compile LVM for you. *--*[*no-*]*mdadm*:: Includes or excludes mdadm support. When enabled, this will compile mdadm for you. *--mdadm-config*=:: Use as configfile for MDADM. By default the ramdisk will be built *without* an 'mdadm.conf' and will auto-detect arrays during boot-up. *--*[*no-*]*microcode-initramfs*:: Prepends, or do not prepend ucode(s) to the initramfs. But only when kernel configuration does support early microcode loading. See *--microcode* option to auto-update kernel configuration. NOTE: Embedding microcode updates into initramfs is *deprecated* when system is able to load multiple initramfs. *--*[*no-*]*dmraid*:: Includes or excludes DMRAID support. When enabled, this will compile dmraid for you. *--*[*no-*]*nfs*:: Includes or excludes NFS support. *--*[*no-*]*e2fsprogs*:: Includes or excludes e2fsprogs. When enabled, this will compile e2fsprogs for you. *--*[*no-*]*xfsprogs*:: Includes or excludes xfsprogs. When enabled, this will compile xfsprogs for you. *--*[*no-*]*zfs*:: Includes or excludes ZFS support. *--*[*no-*]*btrfs*:: Includes or excludes Btrfs support. When enabled, this will compile btrfs-progs for you. *--*[*no-*]*multipath*:: Includes or excludes Multipath support. When enabled, this will compile multipath-tools for you. *--*[*no-*]*iscsi*:: Includes or excludes iSCSI support. When enabled, this will compile open-iscsi for you. *--*[*no-*]*sandbox*:: Enables or disables sandbox-ing when building initramfs. *--*[*no-*]*ssh*:: Includes or excludes SSH (dropbear) support for remote LUKS keys. When enabled, this will compile dropbear for you. *--ssh-authorized-keys-file*=:: Specifies a user created authorized_keys file. By default genkernel will use '/etc/dropbear/authorized_keys'. *--ssh-host-keys*=:: When set to *create*, which is the default value, genkernel will embed SSH host keys from '/etc/dropbear' and will create those keys when missing. When set to *create-from-host*, genkernel will embed SSH host keys from '/etc/dropbear' but will create those keys from '/etc/ssh' when missing (not recommended for security reasons). When set to *runtime*, genkernel will not embed any SSH host key in initramfs and dropbear will generate needed host key at runtime (`dropbear -R`). *--boot-font*=|none>:: When set to *current*, genkernel will use "setfont" to dump and embed current active console font into initramfs. When set to a *PC Screen Font file*, genkernel will embed that font into initramfs. When set to *none*, genkernel will not embed any font file in initramfs. In case a font was embedded into initramfs, genkernel will load that font early on boot. See *gk.bootfont.disabled* kernel parameter for disabling that feature at runtime. *--bootloader*=:: Add new kernel to GRUB or GRUB2 configuration. *--linuxrc*=:: Use for the linuxrc instead of the genkernel linuxrc. *--busybox-config*=:: Specifies a user created busybox config. *--genzimage*:: Make and install kernelz image from 'arch/powerpc/boot/zImage.initrd'. *--*[*no-*]*luks*:: Includes or excludes LUKS support. When enabled, this will compile cryptsetup for you. *--*[*no-*]*gpg*:: Includes or excludes support for GnuPG 1.x, the portable standalone branch of GnuPG. A key can be made from `gpg --symmetric -o /path/to/LUKS-key.gpg /path/to/LUKS-key` . After that, re-point the *root_key* argument to the new .gpg file. *--*[*no-*]*keyctl*:: Includes or excludes support for keyutils keyctl. This way a LUKS passphrase can be loaded into a keyring at boot time to unlock multiple devices (root, swap, etc.) without retyping it for each one. *--*[*no-*]*b2sum*:: Includes or excludes b2sum in the initramfs. When enabled, this will compile coreutils' b2sum for you. *--*[*no-*]*busybox*:: Includes or excludes busybox in the initramfs. When enabled, this will compile busybox for you. *--*[*no-*]*unionfs*:: Includes or excludes support for unionfs. When enabled, this will compile unionfs-fuse for you. *--*[*no-*]*netboot*:: Creates or does not create a self-contained env in the initramfs. *--real-root*=:: Specify a default for *real_root*= kernel option which will be embedded into initramfs. INTERNALS ~~~~~~~~~ *--cachedir*=:: Override the default cache location. *--check-free-disk-space-bootdir*=:: When set to a non-zero value, genkernel will check early on start for specified amount of free disk space in megabyte in *BOOTDIR*. *--check-free-disk-space-kerneloutputdir*=:: When set to a non-zero value, genkernel will check early on start for specified amount of free disk space in megabyte in *KERNEL_OUTPUTDIR*. *--*[*no-*]*clear-cachedir*:: Clears or skips clearing all files in cache location on genkernel start. *--tmpdir*=:: Sets genkernel's temporary working directory to . By default, a directory below '/var/tmp/genkernel' will be used. *--*[*no-*]*postclear*:: Clears or skips clearing all tmp files and caches after genkernel has run. OUTPUT SETTINGS ~~~~~~~~~~~~~~~ *--initramfs-filename*=<...>:: Set initramfs filename which will be used when initramfs will be installed into *BOOTDIR* (implies *--install* option). Please see *--kernel-filename* option for available placeholders and restrictions. + By default, initramfs filename will be set to 'initramfs-%%KV%%.img'. *--initramfs-symlink-name*=<...>:: Set initramfs symlink name which will be used when initramfs will be installed into *BOOTDIR* (implies *--install* option) and *--symlink* option is given. Please see *--kernel-filename* option for available placeholders and restrictions. + By default, initramfs symlink name will be set to 'initramfs'. NOTE: Initramfs filename and initramfs symlink name must be different. *--minkernpackage*=:: Archive file created using tar containing kernel and initramfs. NOTE: No modules outside of the initramfs will be included! *--modulespackage*=:: Archive file created using tar containing modules after the callbacks have run. *--kerncache*=:: Archive file created using tar containing kernel binary, content of '/lib/modules' and the kernel config after the callbacks have run. *--kernel-config-filename*=<...>:: Set the kernel config filename used by *--save-config*. Please see *--kernel-filename* option for available placeholders and restrictions. + By default, kernel config filename will be set to 'kernel-config-%%KV%%'. *--kernel-filename*=<...>:: Set kernel filename which will be used when kernel will be installed into *BOOTDIR* (implies *--install* option). The following placeholders are available: + [horizontal] *%%ARCH%%*::: Will be replaced with genkernel arch value, for example 'x86_64'. *%%KV%%*::: Will be replaced with kernel version, for example '5.2.3-gentoo'. + Kernel filename is only allowed to contain characters like 'a-z' or 'A-Z', '0-9', '_', '.' and '-'. + By default, kernel name will be set to 'vmlinuz-%%KV%%'. NOTE: When setting a custom kernel name make sure that your bootloader and tools like *kexec* when used are recognizing your custom kernel name. *--*[*no-*]*kernel-sources*:: This option is only valid if kerncache is defined If there is a valid kerncache no checks will be made against a kernel source tree. *--kernel-symlink-name*=<...>:: Set kernel symlink name which will be used when kernel will be installed into *BOOTDIR* (implies *--install* option) and *--symlink* option is given. Please see *--kernel-filename* option for available placeholders and restrictions. + By default, kernel symlink name will be set to 'kernel'. NOTE: Kernel filename and kernel symlink name must be different. *--systemmap-filename*=<...>:: Set System.map filename which will be used when kernel will be installed into *BOOTDIR* (implies *--install* option). Please see *--kernel-filename* option for available placeholders and restrictions. + By default, System.map filename will be set to 'System.map-%%KV%%'. *--systemmap-symlink-name*=<...>:: Set System.map symlink name which will be used when kernel will be installed into *BOOTDIR* (implies *--install* option) and *--symlink* option is given. Please see *--kernel-filename* option for available placeholders and restrictions. + By default, System.map symlink name will be set to 'System.map'. NOTE: System.map filename and System.map symlink name must be different. *--initramfs-overlay*=:: Directory structure to include in the initramfs, only available on >=2.6 kernels. *--*[*no-*]*firmware*:: Enable or disables copying of firmware into initramfs. *--*[*no-*]*all-firmware*:: Enable or disable copying of all firmware into initramfs *--firmware-dir*=:: Specify directory to copy firmware from (defaults to '/lib/firmware'). *--firmware-files*=:: Specifies specific firmware files or directories to copy, relative to *--firmware-dir*. For multiple files, separate the filenames with a comma. *--*[*no-*]*firmware-install*:: Enable or disables installation of firmware onto root filesystem. Please note this is deprecated, and installing *sys-kernel/linux-firmware* should be preferred instead. *--*[*no-*]*integrated-initramfs*:: Builds or does not build the generated initramfs into the kernel instead of keeping it as a separate file. *--*[*no-*]*wrap-initrd*:: Wrap initramfs using mkimage for u-boot boots. Please note that only certain compression types are supported by mkimage (see manpage). *--*[*no-*]*compress-initramfs*:: Compresses or does not compress the generated initramfs. *--*[*no-*]*compress-initrd*:: Deprecated alias for *--*[*no-*]*compress-initramfs*. *--compress-initramfs-type*=:: Compression type for initramfs (best, bzip2, fastest, gzip, lz4, lzma, lza, xz, zstd). + *best* will select the algorithm providing best compression from those selected in your kernel configuration. + *fastest* will select the algorithm providing fastest decompression from those selected in your kernel configuration. *--strip*=:: Strip debug symbols from none, all, installed kernel (obsolete) or modules (default). *--no-strip*:: Alias for *--strip=none*. RAMDISK/INITRAMFS OPTIONS ------------------------- The following options are some of those available to be passed as kernel parameters from the bootloader. Genkernel will not handle this operation, please refer to your bootloader documentation for a more complete description of each. This listing is intended to cover most of the options recognized by the ramdisk/initramfs scripts, as well as some of the common options recognized by the kernel itself. *root*=<...>:: Specifies the device node of the root filesystem to mount. *real_root*=<...>:: Legacy kernel parameter from kernel-2.4 initrd. Does the same as *root*=, which should be used in its place. *crypt_root*=<...>:: This specifies the device encrypted by LUKS, which contains the root filesystem to mount. *crypt_root_options*=<...>:: This specifies additional options, which should get passed to cryptsetup when opening root volume. Can be specified multiple times or separate multiple options with a comma. *crypt_swap*=<...>:: This specifies the swap device encrypted by LUKS. *crypt_swap_options*=<...>:: This specifies additional options, which should get passed to cryptsetup when opening swap volume. Can be specified multiple times or separate multiple options with a comma. *root_header*=<...>:: In case your encrypted root uses a LUKS detached header, you can use a device like a usb pen to store the header file. This value should be the key path relative to the mount point. *root_headerdev*=<...>:: If necessary provide the name of the device that carries the root_header. If unset while using root_header, it will automatically look for the device in every boot. *root_headerdev_fstype*=<...>:: Used filesystem for *root_headerdev*. See *rootfstype* for more details. *root_key*=<...>:: In case your root is encrypted with a key, you can use a device like a usb pen to store the key. This value should be the key path relative to the mount point. *root_keydev*=<...>:: If necessary provide the name of the device that carries the root_key. If unset while using root_key, it will automatically look for the device in every boot. *root_keydev_fstype*=<...>:: Used filesystem for *root_keydev*. See *rootfstype* for more details. *root_trim*=(yes|no):: Enables TRIM support for a LUKS-based root device. Only useful with SSD setups. Have a look at 'https://en.wikipedia.org/wiki/TRIM' for more information. *swap_header*=<...>:: Same as root_header for swap. *swap_headerdev*=<...>:: Same as root_headerdev for swap. *swap_headerdev_fstype*=<...>:: Used filesystem for *swap_headerdev*. See *rootfstype* for more details. *swap_key*=<...>:: Same as root_key for swap. *swap_keydev*=<...>:: Same as root_keydev for swap. *swap_keydev_fstype*=<...>:: Used filesystem for *swap_keydev*. See *rootfstype* for more details. *keyctl_keydesc*=<...>:: Load a passphrase into a keyring at boot time under the key name provided as an argument to this option. This way multiple devices (root, swap, etc.) can be unlocked without retyping the passphrase for each one. You'll need to add this key name as a keyring token to every LUKS device that it is supposed to unlock - have a look at cryptsetup 'token add' operation. *keyctl_keykeep*:: Don't remove the newly added key before starting the real init. Useful if you want to utilize it to unlock LUKS devices post-initramfs. *keyctl_keytimeout*=<...>:: Enable a timeout (in seconds) for the newly added key. This option normally only makes sense when used together with the *keyctl_keykeep* option. *crypt_silent*:: Set this to silent all the output related to the cryptographic software, and in case your encrypted device isn't open with the key, it opens a shell in the initrd quietly. *dodmraid*[=<...>]:: Activate Device-Mapper RAID and (optionally) pass arguments to it. *init*=<...>:: Override location of init script, default is "/sbin/init". *real_init*=<...>:: Legacy kernel parameter from kernel-2.4 initrd. Does the same as *init*=, which should be used in its place. *init_opts*=<...>:: Passes arguments to init on bootup. *scandelay*[=<...>]:: Pauses for 10 seconds before running devfsd if no argument is specified; otherwise pauses for the number of specified seconds. *rootdelay*[=<...>]:: *rootwait*[=<...>]:: Pauses for up to 3 seconds (or specified number of seconds) while waiting for root device to appear during initramfs root scanning. *ip*=:: Normally used to tell the kernel that it should start a network interface which can be specified using *gk.net.iface* kernel parameter. By default, dhcp will be used. You can set a specific IP address using addr/CIDR notation, i.e. '1.2.3.4/24'. *gk.net.dhcp.retries*=<...>:: By default we will send up to 3 DHCP discovery requests. *gk.net.iface*=:: By default we will use the interface named eth0. Use this kernel parameter to specify another interface. You can also specify a MAC address (00:00:00:00:00:00 format) instead of an interface name. *gk.net.gw*=<...>:: Optional gateway. If *ip* is set to dhcp, this kernel parameter will be ignored. *gk.net.routes*=<...>:: Optional additional routes. If *ip* is set to dhcp, this kernel parameter will be ignored. *gk.net.timeout.dad*=<...>:: By default we will wait up to 10 seconds for IPv6's DAD to complete. At the moment, we only wait for DAD while bringing down an interface to prevent a race condition. *gk.net.timeout.deconfiguration*=<...>:: By default we will wait up to 10 seconds while bringing down an interface to prevent a race condition. *gk.net.timeout.dhcp*=<...>:: By default we will wait up to 10 seconds for a DHCP server reply. *gk.net.timeout.interface*=<...>:: By default we will wait up to 10 seconds for interface to show up. *gk.udev.debug*=<...>:: This boolean option allows you to run udevd in debug mode. Output will be logged to '/run/initramfs/udevd.log'. *gk.udev.timeout*=<...>:: By default we will wait up to 120 seconds (UDEV default) for UDEV event queue to become empty. *gk.preserverun.disabled*=<...>:: By default, *switch_root* will preserve and move already mounted '/run' to *newroot*. This boolean option allows you to disable preserving of '/run', which is maybe required for SELinux due to missing labeling support in genkernel. *gk.prompt.timeout*=<...>:: By default a prompt within genkernel initramfs like shown when set *root* could not be found will never timeout. Use this option to set a timeout. NOTE: When *dosshd* is used, *gk.prompt.timeout* will be set to 30 seconds when not set. This will allow remote user to provide answer through *GK_PROMPT_FILE* which is set to '/tmp/current_prompt' by default. *dosshd*:: Will bring up an interface and start a SSH daemon within initramfs allowing to remotely unlock encrypted devices or just for debugging purpose. See *ip* option for how to configure network. *gk.sshd.port*=<...>:: By default, sshd will listen on port 22. *gk.sshd.wait*=<...>:: Wait X seconds after setting up sshd, useful when you want to login (and thus pause boot process) before booting real system. *nfsroot*=<...>:: If present, the initrd will try to mount a livecd from that location. Otherwise the location will be deduced from the DCHP request (option root-path). *dolvm*:: Activate LVM volumes on bootup. *domdadm*:: Scan for RAID arrays on bootup. *dozfs*[=cache,force]:: Scan for bootable ZFS pools on bootup. Optionally use cachefile or force import if necessary or perform both actions. *domultipath*:: Activate Multipath on bootup. *doscsi*:: Activate SCSI devices on bootup, necessary when SCSI support is compiled as modules and you're using SCSI or SATA devices. *keymap*='MAP':: Set keymap to 'MAP', e.g. *keymap*=de. For valid values of 'MAP' please see '/usr/share/genkernel/defaults/keymaps/'. *dokeymap*:: Use keymap. Usage of *keymap*= implies this option, already. *rootfstype*=<...>:: Specify the file system type to mount the real root filesystem as. This can be useful when support for ext2/ext3/ext4 are in competition or used filesystem was not built into kernel. Default is "auto". *docache*:: *nocache*:: Enables/disables caching of CD contents in RAM. *subdir*=<...>:: switch_root into "/" instead of "/". is "/newroot" (or "/union") usually. *quiet_genkernel*:: Do not print anything but error and warning messages during the execution of the initramfs init scripts. *quiet*:: Implies *quiet_genkernel*, but also recognized by the kernel to suppress kernel messages. *debug*:: Drop into a debug shell early in the process. *gk.bootfont.disabled*=<...>:: By default, if a bootfont is embedded within initramfs, genkernel will load that font. This boolean option allows you to disable loading of the user embedded bootfont. *gk.emergency*=:: By default, genkernel tries to spawn a rescue shell in case of a critical failure (see *gk.userinteraction.disabled* to prevent this). This option controls the action to execute when rescue is not possible. Default is "halt". *gk.hw.load-all*=<...>:: By default, genkernel loads various module groups (nvme, sata, scsi, pata, usb...) until block device specified in *root* parameter becomes available. This boolean option allows you to force loading of all module groups regardless whether root device is already available. *gk.hw.use-modules_load*=<...>:: By default, genkernel relies on UDEV's capability to load required kernel modules. This boolean option allows you to force old module loading depending on modules_load file until *root* device becomes available. *gk.log.disabled*=<...>:: By default, any shown message and external command calls will be logged to '/run/initramfs/init.log'. This boolean option allows you to disable logging for some reason. *gk.userinteraction.disabled*=<...>:: By default, genkernel will prompt on errors. In case this is not wanted or desired, e.g. for a kiosk system, this boolean option will disable any prompting, including the rescue shell. NOTE: Because no user interaction is possible when this option is set, on error, system will immediately execute *gk.emergency* action. *noload*=<...>:: List of modules to skip loading. Separate using commas or spaces. NOTE: This option has only an effect when *gk.hw.use-modules_load* is enabled. *doload*=<...>:: List of modules which should always be loaded. *domodules*:: *nomodules*:: Enables/disables loading of modules in general. *part*[=<0,1>]:: *partitionable*:: Enable/Disable partitionable RAIDs (metadata 0.x) during auto-run. Standalone *part* and *partitionable* keywords for kernel compatability. *iscsi_initiatorname*=<...>:: *iscsi_target*=<...>:: *iscsi_tgpt*=<...>:: *iscsi_address*=<...>:: *iscsi_port*=<...>:: *iscsi_username*=<...>:: *iscsi_password*=<...>:: *iscsi_username_in*=<...>:: *iscsi_password_in*=<...>:: *iscsi_debug*=<...>:: *iscsi_noibft*:: Specify iSCSI parameters. *unionfs*:: *nounionfs*:: Enables/disables UnionFS. *aufs*:: Enables support for AUFS (if available in the kernel). *aufs.modules*=<...>:: Use an alternate location for filesystem overlays to be added on top of the livecd and below the writable tmpfs. Default is /modules/. *overlayfs*:: Enables support for Overlayfs (if available in the kernel). *overlayfs.modules*=<...>:: Use an alternate location for filesystem overlays to be added on top of the livecd and below the writable tmpfs. Default is /modules/ *rootflags*=<...>:: Additional flags to mount the real root system with. For example *rootflags*=noatime would make "-o ro,noatime". *real_rootflags*=<...>:: Legacy kernel parameter from kernel-2.4 initrd. Does the same as *rootflags*=, which should be used in its place. *real_resume*=<...>:: *resume*=<...>:: *noresume*:: *noresume* disables any default resume parameters. *resume* and *real_resume* specify a device via LABEL or UUID to use for for loading a TuxOnICE, SWSUSP or Suspend2 resume image. *cdroot*[=<...>]:: *cdroot_type*=<...>:: *cdroot_marker*=<...>:: Used for LiveCDs. *cdroot* without arguments will cause the initramfs to scan all devices for a LiveCD. An argument to *cdroot* will cause it to scan only that device. A LiveCD is any device containing a file with the name & Path of *cdroot_marker* (default of "/livecd"). *cdroot_type* (default of "auto") is the filesystem type to use while mounting devices to check. On success, the LiveCD will be mounted at $CDROOT_PATH. *loop*=<...>:: *looptype*=<...>:: Used for LiveCDs. After mounting the LiveCD or ISO, look for a file at *loop*=path to use as a loopback image for the main type. Mount it with filesystem type *looptype*. Possible values for *looptype*: normal, squashfs, gcloop, zisofs, noloop, sgimips. If *looptype* is not specified, a guess is made, based on the name or extension of *loop*. *isoboot*=<...>:: Loop-mount an ISO file from the boot device to get the filesystem image. Useful with chain-loading environments and USB keys. initramfs.mounts ---------------- By default, genkernel's initramfs will only mount *root* device. But sometimes additional mounts are required before initramfs can switch to real root (for example on systems with a seperate '/usr' mount). Therefore genkernel package contains '/etc/initramfs.mounts' file which will allow you to specify additional mounts which should be mounted before initramfs will switch to real root. NOTE: This file will not be included in initramfs. Instead, booted initramfs will check for this file on specified *root* device. NETBOOTING ---------- The initrd scripts have limited support for network booting. This is activated if the *ip*=<...> kernel parameter was given. Please refer to the genkernel guide at 'https://wiki.gentoo.org/wiki/Genkernel' for more information. The initrd scripts will extract any *.tar.gz files found in the '/add' directory of the livecd into the root filesystem during boot. This way it is easy to extend a netbooted LiveCD i.e. add custom tools, or other kernel modules. REPORTING BUGS -------------- If you believe you have found a bug in the genkernel scripts, then please file a bug on the Gentoo Linux Bugzilla against product "Gentoo Hosted Projects" component "genkernel", i.e. at 'https://bugs.gentoo.org/enter_bug.cgi?product=Gentoo%20Hosted%20Projects&component=genkernel'. If you're somewhat unsure if you hit a bug or not, file a bug an we'll find out together. For general questions the is the gentoo-genkernel mailing list. You can join the list by sending empty mail to 'gentoo-genkernel+subscribe@lists.gentoo.org'. We cannot assist you with kernel compilation failures unless they are caused by a genkernel bug. Kernel issues for Gentoo-supported kernels, including compilation failures should go to 'https://bugs.gentoo.org/' and should be assigned to 'kernel@gentoo.org'. Please check if an existing bug documents the same issue before opening a new bug. Issues for kernel sources not supported by Gentoo should go to their relevant authors. AUTHORS ------- - Tim Yamin - Eric Edgar - Chris Gianelloni - Sebastian Pipping - Robin H. Johnson - Thomas Deutschmann - NFS Support by Thomas Seiler - GnuPG 1.x integration by dacook - MDADM integration by Matthias Dahl - ZFS integration by Richard Yao - AUFS/Overlayfs by Zero_Chaos and likewhoa SEE ALSO -------- '/etc/initramfs.mounts' - additional required mounts before switching to real root '/etc/genkernel.conf' - genkernel configuration file // vim: ft=asciidoc et tw=72 sts=4 ts=4 :