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

Provided by: kdump-tools_1.8.1ubuntu1_amd64

NAME

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

SYNOPSIS

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

DESCRIPTION

       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.

COMMANDS

       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-config
              load.

       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.

FILES

       /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

DIAGNOSTICS

USE_KDUMP is not set or zero
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.

kdump is not supported by this kernel
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.

no crashkernel= parameter in the kernel cmdline
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_KERNEL does not exist: $KDUMP_KERNEL
A KDUMP_KERNEL was specified in /etc/default/kdump-tools, but it cannot be found.

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

no KDUMP_KERNEL in $KDUMP_DEFAULTS and
can't find a kdump package directory in /usr/lib
no kdump kernel could be found.

found a linux-kdump package in $KDUMP_PKG_DIR
but can't find a kdump kernel in $KDUMP_PKG_DIR
this indicates a broken linux-kdump package installation.

no kdump initrd image: $KDUMP_INITRD
an initrd will not be used
this indicates that although a kdump kernel was found, a corresponding initrd was
not found.

kdump kernel relocation address does not match crashkernel= 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.

failed to load kdump kernel
kexec reported that it could not load the kdump kernel.

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

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

failed to save vmcore in $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.

Invalid argument : missing kernel version
The symlinks command was used with a kernel version that is not installed on this
server

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

Cannot change symbolic links when kdump is loaded
The defined symbolic links are already in use. You must unload kdump before using
the symlinks command

Unable to locate kernel hook
The kdump-tools script responsible for the creation of smaller initrd.img files is
absent from /usr/kernel/postinst.d

Invalid kernel version : {kernel version}
The kernel version given to the symlinks command does not exist

fadump is not configured in this kernel.
The Firmware Assisted Dump (fadump) facility is not available on this platform

SSH and NFS cannot be defined concurrently
Both variables are defined in /etc/default/kdump-tools. You must choose one or the
other as configuration option.

Unable to mount remote NFS directory {directory}. Cannot save core
The remote NFS server does not authorize this server to mount the directory to save
the crash dump.

Unable to write to the remote NFS directory {directory}. Cannot save core
The remote NFS directory can be mounted but this server cannot write files to it.

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

Unable to reach remote server {server}. No reason to continue
kdump-tools is configured for remote dump but the remote server cannot be reached.

makedumpfile scp failed. The vmcore file will not be available
The makedumpfile command was successful but the resulting file could not be copied
over SSH to the remote server.

Remote ssh dump is not configured. No reason to propagate"
The propagate command was used but kdump is not configured for remote dump.

AUTHOR

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