kexec-tools/kdumpctl.8
Coiby Xu 3f828198af rewrite reset_crashkernel to support fadump and to used by RPM scriptlet
Resolves: bz1895258
Upstream: Fedora
Conflict: None

commit 140da74a34
Author: Coiby Xu <coxu@redhat.com>
Date:   Wed Dec 1 13:39:40 2021 +0800

    rewrite reset_crashkernel to support fadump and to used by RPM scriptlet

    Rewrite kdumpctl reset-crashkernel KERNEL_PATH as
    kdumpctl reset-crashkernel [--fadump=[on|off|nocma]]  [--kernel=path_to_kernel] [--reboot]

    This interface would reset a specific kernel to the default crashkernel value
    given the kernel path. And it also supports grubby's syntax so there are the
    following special cases,
     - if --kernel not specified,
        - use KDUMP_KERNELVER if it's defined in /etc/sysconfig/kdump
        - otherwise use current running kernel, i.e. `uname -r`
     - if --kernel=DEFAULT, the default boot kernel is chosen
     - if --kernel=ALL, all kernels would have its crashkernel reset to the
       default value and the /etc/default/grub is updated as well

    --fadump=[on|off|nocma] toggles fadump on/off for the kernel provided
    in KERNEL_PATH. If --fadump is omitted, the dump mode is determined by
    parsing the kernel command line for the kernel(s) to update.

    CoreOS/Atomic/Silverblue needs to be treated as a special case because,
     - "rpm-ostree kargs" is used to manage kernel command line parameters
        so --kernel doesn't make sense and there is no need to find current
        running kernel
     - "rpm-ostree kargs" itself would prompt the user to reboot the system
       after modify the kernel command line parameter
     - POWER is not supported so we can assume the dump mode is always kdump

    This interface will also be called by kexec-tools RPM scriptlets [1]
    to reset crashkernel.

    Note the support of crashkenrel.default is dropped.

    [1] https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/

    Reviewed-by: Pingfan Liu <piliu@redhat.com>
    Reviewed-by: Philipp Rudo <prudo@redhat.com>
    Signed-off-by: Coiby Xu <coxu@redhat.com>

Signed-off-by: Coiby Xu <coxu@redhat.com>
2022-01-06 03:55:25 +00:00

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2.0 KiB
Groff

.TH KDUMPCTL 8 2015-07-13 kexec-tools
.SH NAME
kdumpctl \- control interface for kdump
.SH SYNOPSIS
.B kdumpctl
.I COMMAND
.SH DESCRIPTION
.B kdumpctl
is used to check or control the kdump service.
In most cases, you should use
.B systemctl
to start / stop / enable kdump service instead. However,
.B kdumpctl
provides more details for debug and a helper to setup ssh key authentication.
.SH COMMANDS
.TP
.I start
Start the service.
.TP
.I stop
Stop the service.
.TP
.I status
Prints the current status of kdump service.
It returns non-zero value if kdump is not operational.
.TP
.I restart
Is equal to
.I start; stop
.TP
.I reload
reload crash kernel image and initramfs without triggering a rebuild.
.TP
.I rebuild
rebuild the crash kernel initramfs.
.TP
.I propagate
Helps to setup key authentication for ssh storage since it's
impossible to use password authentication during kdump.
.TP
.I showmem
Prints the size of reserved memory for crash kernel in megabytes.
.TP
.I estimate
Estimate a suitable crashkernel value for current machine. This is a
best-effort estimate. It will print a recommanded crashkernel value
based on current kdump setup, and list some details of memory usage.
.TP
.I reset-crashkernel [--kernel=path_to_kernel] [--reboot]
Reset crashkernel to default value recommended by kexec-tools. If no kernel
is specified, will reset KDUMP_KERNELVER if it's defined in /etc/sysconfig/kdump
or current running kernel's crashkernel value if KDUMP_KERNELVER is empty. You can
also specify --kernel=ALL and --kernel=DEFAULT which have the same meaning as
grubby's kernel-path=ALL and kernel-path=DEFAULT. ppc64le supports FADump and
supports an additonal [--fadump=[on|off|nocma]] parameter to toggle FADump
on/off.
Note: The memory requirements for kdump varies heavily depending on the
used hardware and system configuration. Thus the recommended
crashkernel might not work for your specific setup. Please test if
kdump works after resetting the crashkernel value.
.SH "SEE ALSO"
.BR kdump.conf (5),
.BR mkdumprd (8)