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RHEL 9.0.0 Alpha bootstrap The content of this branch was automatically imported from Fedora ELN with the following as its source: https://src.fedoraproject.org/rpms/kexec-tools#041ba89902961b5490a7143d9596dc00d732cba0
2020-10-15 12:45:57 +00:00
.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.
kdumpctl: Add kdumpctl estimate Resolves: bz1951415 Upstream: fedora Conflict: none commit e9e6a2c745d41f5447c0062525c0e4f3f489b903 Author: Kairui Song <kasong@redhat.com> Date: Thu Apr 22 03:27:10 2021 +0800 kdumpctl: Add kdumpctl estimate Add a rough esitimation support, currently, following memory usage are checked by this sub command: - System RAM - Kdump Initramfs size - Kdump Kernel image size - Kdump Kernel module size - Kdump userspace user and other runtime allocated memory (currently simply using a fixed value: 64M) - LUKS encryption memory usage The output of kdumpctl estimate looks like this: # kdumpctl estimate Reserved crashkernel: 256M Recommanded crashkernel: 160M Kernel image size: 47M Kernel modules size: 12M Initramfs size: 19M Runtime reservation: 64M Large modules: xfs: 1892352 nouveau: 2318336 And if the kdump target is encrypted: # kdumpctl estimate Encrypted kdump target requires extra memory, assuming using the keyslot with minimun memory requirement Reserved crashkernel: 256M Recommanded crashkernel: 655M Kernel image size: 47M Kernel modules size: 12M Initramfs size: 19M Runtime reservation: 64M LUKS required size: 512M Large modules: xfs: 1892352 nouveau: 2318336 WARNING: Current crashkernel size is lower than recommanded size 655M. The "Recommanded" value is calculated based on memory usages mentioned above, and will be adjusted accodingly to be no less than the value provided by kdump_get_arch_recommend_size. Signed-off-by: Kairui Song <kasong@redhat.com> Acked-by: Pingfan Liu <piliu@redhat.com> Signed-off-by: Kairui Song <kasong@redhat.com>
2021-04-21 19:27:10 +00:00
.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.
kdumpctl: Add kdumpctl reset-crashkernel Resolves: bz1974638 Upstream: Fedora Conflict: None commit 86130ec10fda37cc283f717eaacb56a4cbf76418 Author: Kairui Song <kasong@redhat.com> Date: Thu Jun 10 13:06:22 2021 +0800 kdumpctl: Add kdumpctl reset-crashkernel In newer kernel, crashkernel.default will contain the default crashkernel value of a kernel build. So introduce a new sub command to help user reset kernel crashkernel size to the default value. Signed-off-by: Kairui Song <kasong@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Signed-off-by: Kairui Song <kasong@redhat.com>
2021-06-10 05:06:22 +00:00
.TP
rewrite reset_crashkernel to support fadump and to used by RPM scriptlet Resolves: bz1895258 Upstream: Fedora Conflict: None commit 140da74a340f872b2579fc75b50a36fe7015c0ba 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>
2022-01-05 03:53:09 +00:00
.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.
kdumpctl: Add kdumpctl reset-crashkernel Resolves: bz1974638 Upstream: Fedora Conflict: None commit 86130ec10fda37cc283f717eaacb56a4cbf76418 Author: Kairui Song <kasong@redhat.com> Date: Thu Jun 10 13:06:22 2021 +0800 kdumpctl: Add kdumpctl reset-crashkernel In newer kernel, crashkernel.default will contain the default crashkernel value of a kernel build. So introduce a new sub command to help user reset kernel crashkernel size to the default value. Signed-off-by: Kairui Song <kasong@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Signed-off-by: Kairui Song <kasong@redhat.com>
2021-06-10 05:06:22 +00:00
rewrite reset_crashkernel to support fadump and to used by RPM scriptlet Resolves: bz1895258 Upstream: Fedora Conflict: None commit 140da74a340f872b2579fc75b50a36fe7015c0ba 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>
2022-01-05 03:53:09 +00:00
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.
RHEL 9.0.0 Alpha bootstrap The content of this branch was automatically imported from Fedora ELN with the following as its source: https://src.fedoraproject.org/rpms/kexec-tools#041ba89902961b5490a7143d9596dc00d732cba0
2020-10-15 12:45:57 +00:00
.SH "SEE ALSO"
.BR kdump.conf (5),
.BR mkdumprd (8)
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