KDUMP.CONF(5)KDUMP.CONF(5)NAMEkdump.conf - configuration file for kdump kernel.
DESCRIPTIONkdump.conf is a configuration file for the kdump kernel crash collec‐
tion service.
kdump.conf provides post-kexec instructions to the kdump kernel. It is
stored in the initrd file managed by the kdump service. If you change
this file and do not want to restart before it takes effect, restart
the kdump service to rebuild to initrd.
For most configurations, you can simply review the examples provided in
the stock /etc/kdump.conf.
NOTE: kdump.conf only affects the behavior of the initramfs. Please
read the kdump operational flow section of kexec-kdump-howto.txt in the
docs to better understand how this configuration file affects the
behavior of kdump.
OPTIONS
path <path>
Append path to the filesystem device which you are dumping to.
Ignored for raw device dumps. If unset, will default to
/var/crash.
core_collector <command> <options>
This allows you to specify the command to copy the vmcore. You
could use the dump filtering program makedumpfile, the default
one, to retrieve your core, which on some arches can drastically
reduce core file size. See /usr/sbin/makedumpfile --help for a
list of options. Note that the -i and -g options are not needed
here, as the initrd will automatically be populated with a con‐
fig file appropriate for the running kernel.
If you use other command as a core_collector, probably you also
need to provide its full path in extra_bins. Note, for ssh dump,
scp should be used instead of cp.
raw <partition>
Will write /proc/vmcore into raw <partition>.
nfs <nfs mount> | nfs4 <nfs mount> | net <nfs mount>
Will mount fs and copy /proc/vmcore to
<mnt>/<path>/%HOST-%DATE/, supports DNS. Note that a fqdn should
be used as the server name in the mount point. By default, NFSv3
is used, nfs4 will use NFSv4. "net" is deprecated by "nfs"
ssh <user@server> | net <user@server>
Will copy /proc/vmcore to <user@server>:<path>/%HOST-%DATE/ via
SSH, supports DNS. If makedumpfile is the core_collector, it is
piped to an "ssh" shell, otherwise use the specified core_col‐
lector like scp. NOTE: make sure user has necessary write per‐
missions on server and that a fqdn is used as the server name.
"net" is deprecated by "ssh"
<fs type> <partition>
Will mount -t <fs type> <partition> /mnt and copy /proc/vmcore
to /mnt/<path>/127.0.0.1-%DATE/. Currently, the supported fs
types are: ext4, ext3, ext2, minix, btrfs and xfs, other fs
types like "auto" are not supported. NOTE: <partition> can be a
device node, label or uuid.
disk_timeout <seconds>
Number of seconds to wait for disks to appear prior to continue
to save dump. By default kdump waits 180 seconds for the disks
to show up it needs. This can be useful in some cases if disk
never shows up (Either because disk was removed or because kdump
is waiting on wrong disk).
link_delay <seconds>
Some network cards take a long time to initialize, and some
spanning tree enabled networks do not transmit user traffic for
long periods after a link state changes. This optional parame‐
ter defines a wait period after a link is activated in which the
initramfs will wait before attempting to transmit user data.
kdump_post <binary | script>
This directive allows you to run a specified executable just
after the memory dump process terminates. The exit status from
the dump process is fed to the kdump_post executable, which can
be used to trigger different actions for success or failure.
Note that scripts written for use with this directive must use
the /bin/hush interpreter
kdump_pre <binary | script>
Works just like the kdump_post directive, but instead of running
after the dump process, runs immediately before. Exit status of
this binary is interpreted as follows:
0 - continue with dump process as usual
non 0 - reboot/halt the system
Note that scripts written for this directive must use the
/bin/hush interpreter
extra_bins <binaries | shell scripts>
This directive allows you to specify additional binaries or
shell scripts you'd like to include in your kdump initrd. Gener‐
ally only useful in conjunction with a kdump_post binary or
script that relies on other binaries or scripts.
extra_modules <module(s)>
This directive allows you to specify extra kernel modules that
you want to be loaded in the kdump initrd, typically used to set
up access to non-boot-path dump targets that might otherwise not
be accessible in the kdump environment. Multiple modules can be
listed, separated by a space, and any dependent modules will
automatically be included. Module name should be specified
without ".ko" suffix.
options <module> <option list>
This directive allows you to specify options to apply to modules
in the initramfs. This directive overrides options specified in
/etc/modprobe.conf. Module name should be specified without
".ko" suffix.
blacklist <module|directory>
Prevents modules from being loaded in the initframfs, either
directly during auto-created insmod calss or as a dependency of
another module load. A specific module or a directory can be
specified. In the latter case, all modules found below the
specified directory will be excluded. This directive can be
specified multiple times or as a space separated list. Module
name should be specified without ".ko" suffix.
sshkey <path>
Specifies the path of the ssh key you want to use when do ssh
dump, the default value is /root/.ssh/kdump_id_rsa.
default <reboot | halt | poweroff | shell | mount_root_run_init>
Action to perform in case dumping to intended target fails. If
no default action is specified, "reboot" is assumed default.
reboot: If the default action is reboot simply reboot the system
(this is what most people will want, as it returns the system to
a nominal state).
halt: bring the system to a halt, requiring manual reset.
poweroff: The system will be powered down.
shell: If the default action is shell, then drop to an hush ses‐
sion inside the initramfs from where you can manually perform
additional recovery actions. Exiting this shell reboots the
system.
mount_root_run_init: Mount root filesystem and run init. Kdump
initscript will try to save dump to root filesystem in
/var/crash dir. This will likely require a lot more memory to be
reserved for kdump kernel.
debug_mem_level <0-3>
Turns on debug/verbose output of kdump scripts regarding
free/used memory at various points of execution. Higher level
means more debugging output.
0 - no output
1 - partial /proc/meminfo
2 - /proc/meminfo
3 - /proc/meminfo + /proc/slabinfo
force_rebuild <0 | 1>
By default, kdump initrd only will be rebuilt when necessary.
Specify 1 here to force rebuilding kdump initrd every time when
kdump service starts.
EXAMPLES
see /etc/kdump.conf
SEE ALSOkexec(8)mkdumprd(8)kexec-tools 07/23/2008 KDUMP.CONF(5)
