kdump-config - configure kdump, check status, or save a vmcore file

       Written by Terry Loftin <terry.loftin@hp.com> and Louis Bouchard <louis.bouchard@ubuntu.com>

kdump-tools v1.6.7-2                                Jul 2020                                     kdump-config(8)

help   Print a usage summary.

       test   Determine  the  parameters  that would be used to load the kdump kernel, but do not load the kdump
              kernel.  Useful for evaluating your configuration settings.

       show   Show current parameters and the saved kexec command from the last kdump-configload.

       status Evaluate /sys/kernel/kexec_crash_loaded or /sys/kernel/fadump_register depending on the dump  mode
              and print a corresponding message.

       load   Load the kdump kernel or register if using firmware assisted dump (fadump)

       unload Unload the kdump kernel or unregister if using firmware assisted dump (fadump)

       savecore
              If /proc/vmcore exists, save it using makedumpfile.

       propagate
              Sends public ssh key to remote host for passwordless connection

       symlinks{kernel-version}
              Verify  and create vmlinuz and initrd.img links in /var/lib/kdump according to the provided kernel
              version. If the target initrd.img file is absent, it will create it.

kdump-config manages the kdump feature of the Linux kernel.  When  a  kdump  enabled  kernel  panics,  it
       immediately  boots  into a clean kernel called the kdump kernel.  The memory image of the panicked kernel
       will be presented in /proc/vmcore while the kdump kernel (or "capture kernel") is running.

       kdump-config loads the kdump kernel into the current kernel and after a kdump, captures the vmcore  image
       via  kdump  kernel.   kdump-config can take advantage of the linux-image-$(uname-r)-dbg package and will
       try to use makedumpfile to capture the vmcore.  The crash tool can then be used to analyze the vmcore  at
       a later time.

       kdump-config exits with 0 on success and 1 on failure.

USE_KDUMPisnotsetorzero
              The variable USE_KDUMP in the file /etc/default/kdump-tools
               is 0.  To use kdump, edit the file and change the value to 1.

       kdumpisnotsupportedbythiskernel
              The file /sys/kernel/kexec_crash_loaded does not exist.  This means  that  the  currently  running
              kernel  either  was  not configured to support kdump, or that a crashkernel= commandline parameter
              was not used when the currently running kernel booted.

       nocrashkernel=parameterinthekernelcmdline
              a crashkernel= commandline parameter was not used when the currently running kernel  booted.   You
              will  need  to  add  a  crashkernel=  parameter  to  your  /etc/lilo.conf, /etc/elilo.conf or grub
              /boot/grub/menu.lst  file  and  reboot,  before  kdump  will  work.   See  installed  READMEs  for
              suggestions.

       KDUMP_KERNELdoesnotexist:$KDUMP_KERNEL
              A KDUMP_KERNEL was specified in /etc/default/kdump-tools, but it cannot be found.

       KDUMP_INITRDdoesnotexist:$KDUMP_INITRD
              A KDUMP_INITRD was specified in /etc/default/kdump-tools, but it cannot be found.

       noKDUMP_KERNELin$KDUMP_DEFAULTSandcan'tfindakdumppackagedirectoryin/usr/lib
              no kdump kernel could be found.

       foundalinux-kdumppackagein$KDUMP_PKG_DIRbutcan'tfindakdumpkernelin$KDUMP_PKG_DIR
              this indicates a broken linux-kdump package installation.

       nokdumpinitrdimage:$KDUMP_INITRDaninitrdwillnotbeused
              this indicates that although a kdump kernel was found, a corresponding initrd was not found.

       kdumpkernelrelocationaddressdoesnotmatchcrashkernel=parameter
              For  non-relocatable  architectures,  the  kdump  kernel  must be built with a predetermined start
              address.  This message indicates that the start address of the kdump kernel and the start  address
              in the crashkernel= parameter do not match.

       failedtoloadkdumpkernel
              kexec reported that it could not load the kdump kernel.

       failedtounloadkdumpkernel
              kexec  reported  that  it  could  not  unload  the kdump kernel.  Run 'kexec -u' directly for more
              detail.

       makedumpfilefailed,fallingbackto'cp'
              this message is printed if the kdump-tools init script attempts to save a /proc/vmcore file  using
              makedumpfile and the save fails.

       failedtosavevmcorein$KDUMP_STAMPDIR
              this  message  indicates  that  makedumpfile and the fallback method of using cp has failed.  This
              usually occurs if pathnames are wrong or if the disk is full.

       Invalidargument:missingkernelversion
              The symlinks command was used with a kernel version that is not installed on this server

       Invalidsymlink:{symboliclink}
              The listed symbolic link is absent, broken or pointing to the wrong version

       Cannotchangesymboliclinkswhenkdumpisloaded
              The defined symbolic links are already in use. You must unload kdump  before  using  the  symlinks
              command

       Unabletolocatekernelhook
              The  kdump-tools  script  responsible  for the creation of smaller initrd.img files is absent from
              /usr/kernel/postinst.dInvalidkernelversion:{kernelversion}
              The kernel version given to the symlinks command does not exist

       fadumpisnotconfiguredinthiskernel.
              The Firmware Assisted Dump (fadump) facility is not available on this platform

       SSHandNFScannotbedefinedconcurrently
              Both variables are defined in /etc/default/kdump-tools. You  must  choose  one  or  the  other  as
              configuration option.

       UnabletomountremoteNFSdirectory{directory}.Cannotsavecore
              The  remote  NFS  server  does  not authorize this server to mount the directory to save the crash
              dump.

       UnabletowritetotheremoteNFSdirectory{directory}.Cannotsavecore
              The remote NFS directory can be mounted but this server cannot write files to it.

       makedumpfile--dump-dmesgfailed.dmesgcontentwillbeunavailable
              The command to capture the content of the dmesg buffer failed. It will not  be  available  in  the
              crash directory

       Unabletoreachremoteserver{server}.Noreasontocontinuekdump-tools is configured for remote dump but the remote server cannot be reached.

       makedumpfilescpfailed.Thevmcorefilewillnotbeavailable
              The makedumpfile command was successful but the resulting file could not be copied over SSH to the
              remote server.

       Remotesshdumpisnotconfigured.Noreasontopropagate"
              The propagate command was used but kdump is not configured for remote dump.

/etc/init.d/kdump-tools
                      init script to automatically load a kdump kernel, or save a vmcore and reboot.

       /etc/default/kdump-tools
                      configuration file

       /var/crash/kernel_link
                      a link to the current debug kernel

       /var/crash/kexec_cmd
                      the last kexec_cmd executed by kdump-config/var/lib/kdump/vmlinuz
                      Symbolic link pointing to the current kernel file in /boot/var/lib/kdump/initrd.img
                      Symbolic link pointing to the initrd.img file with the current kernel version in /boot

       kdump-config - configure kdump, check status, or save a vmcore file

/usr/share/doc/kdump-tools/README/usr/share/doc/kdump-tools/README.Debiankdump-tools(5), kexec(8), crash(8), gdb(1), makedumpfile(8)

kdump-config{help|test|show|status|load|unload|savecore|propagate|symlinks{kernel-version}}