On 03/27/18 at 08:19am, Lianbo Jiang wrote:
Kdump service starts too late, so early crashes will have no chance to get kdump kernel booting, this will cause crash information to be lost. It is necessary to add a dracut module in order to load crash kernel and initramfs as early as possible. You can provide "rd.early kdump" in grub commandline to enable, then the early kdump will load those files like the normal kdump, which is disabled by default.
For the normal kdump service, it can check whether the early kdump has loaded the crash kernel and initramfs. It has no conflict with the early kdump.
If you rebuild the new initramfs for early kdump, the new initramfs size will become large, because it will put the vmlinuz and kdump initramfs into the new initramfs.
In addition, early kdump doesn't support fadump.
Signed-off-by: Lianbo Jiang lijiang@redhat.com
dracut-early-kdump-module-setup.sh | 22 +++++++++++ dracut-early-kdump.sh | 81 ++++++++++++++++++++++++++++++++++++++ early-kdump-howto.txt | 62 +++++++++++++++++++++++++++++ kexec-tools.spec | 11 ++++++ 4 files changed, 176 insertions(+) create mode 100755 dracut-early-kdump-module-setup.sh create mode 100755 dracut-early-kdump.sh create mode 100644 early-kdump-howto.txt
diff --git a/dracut-early-kdump-module-setup.sh b/dracut-early-kdump-module-setup.sh new file mode 100755 index 0000000..d47e81a --- /dev/null +++ b/dracut-early-kdump-module-setup.sh @@ -0,0 +1,22 @@ +#!/bin/bash
+check() {
- if [ ! -f /etc/sysconfig/kdump ] || [ ! -f /lib/kdump/kdump-lib.sh ]\
|| [ -n "${IN_KDUMP}" ]- then
return 1- fi
- return 0
+}
+depends() {
- echo "base shutdown"
- return 0
+}
+install() {
- inst_simple "/etc/sysconfig/kdump" "/etc/sysconfig/kdump"
- inst_simple "/usr/sbin/kexec" "/usr/sbin/kexec"
- inst_script "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh"
- inst_hook cmdline 00 "$moddir/early-kdump.sh"
+} diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh new file mode 100755 index 0000000..2a746b4 --- /dev/null +++ b/dracut-early-kdump.sh @@ -0,0 +1,81 @@ +#! /bin/sh
+KEXEC=/sbin/kexec +standard_kexec_args="-p"
+EARLY_KDUMP_INITRD="" +EARLY_KDUMP_KERNEL="" +EARLY_KDUMP_CMDLINE="" +EARLY_KDUMP_KERNELVER="" +EARLY_KEXEC_ARGS=""
+. /etc/sysconfig/kdump +. /lib/dracut-lib.sh +. /lib/kdump-lib.sh
+prepare_parameters() +{
- EARLY_KDUMP_CMDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}" "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")
- KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}")
- #make early-kdump kernel string
- if [ -z "$EARLY_KDUMP_KERNELVER" ]; then
EARLY_KDUMP_KERNELVER=`uname -r`- fi
- EARLY_KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${EARLY_KDUMP_KERNELVER}${KDUMP_IMG_EXT}"
- #make early-kdump initrd string
- EARLY_KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${EARLY_KDUMP_KERNELVER}kdump.img"
+}
+early_kdump_load() +{
- check_kdump_feasibility
- if [ $? -ne 0 ]; then
return 1- fi
- if is_fadump_capable; then
echo "WARNING: early kdump doesn't support fadump."return 1- fi
- check_current_kdump_status
- if [ $? == 0 ]; then
return 1- fi
- prepare_parameters
- EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
- if is_secure_boot_enforced; then
echo "Secure Boot is enabled. Using kexec file based syscall."EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s"- fi
- $KEXEC ${EARLY_KEXEC_ARGS} $standard_kexec_args \
--command-line="$EARLY_KDUMP_CMDLINE" \--initrd=$EARLY_KDUMP_INITRD $EARLY_KDUMP_KERNEL- if [ $? == 0 ]; then
echo "kexec: loaded early-kdump kernel"return 0- else
echo "kexec: failed to load early-kdump kernel"return 1- fi
+}
+set_early_kdump() +{
- if getargbool 0 rd.earlykdump; then
echo "early-kdump is enabled."early_kdump_load- else
echo "early-kdump is disabled."- fi
- return 0
+}
+set_early_kdump diff --git a/early-kdump-howto.txt b/early-kdump-howto.txt new file mode 100644 index 0000000..c8264d8 --- /dev/null +++ b/early-kdump-howto.txt @@ -0,0 +1,62 @@ +Early Kdump HOWTO
+Introduction
+Kdump service starts too late, so early crashes will have no chance to get +kdump kernel booting, this will cause crash information to be lost. It is +necessary to add a dracut module in order to load crash kernel and initramfs +as early as possible. You can provide "rd.earlykdump" in grub commandline +to enable, then the early kdump will load those files like the normal kdump, +which is disabled by default.
+For the normal kdump service, it can check whether the early kdump has loaded +the crash kernel and initramfs. It has no conflict with the early kdump.
+How to configure early kdump:
+We assume if you're reading this document, you should already have kexec-tools +installed.
+For early kdump, if you need to rebuild the initramfs, please manually execute +dracut command:
- # dracut -I ${kdump_kernel} -I ${kdump_initrd} -v ${new_initramfs} --force
It is better to mention file filename should include a absolute path or dracut will silently pass without including the files.
And one should use same path as they set in /etc/sysconfig/kdump about KDUMP_BOOTDIR which is /boot by default. If one pass an initrd like below your early dump will fail: dracut -I /root/kernel -I /tmp/initrd ...
or we can detect and pack kernel/initrd in module-setup.sh automatically. in this way we do not want to overwrite system initrd by default now, maybe change the module-setup.sh check() function to let it return 255 instead return 0 so one can use below command to create an initrd: dracut --add early-kdump
+Parameters: +"${kdump_kernel}" +-It represents kernel image what you put it into the new initramfs. +"${kdump_initrd}"
+-It represents kdump initramfs what you put it into the new initramfs. +"${new_initramfs}" +-It is a new initramfs for early kdump.
+For example: +# dracut -I /boot/vmlinuz-`uname -r` -I /boot/initramfs-`uname -r`kdump.img \ +-v /boot/initramfs-`uname -r`.img --force
+By the way, if you rebuild the new initramfs for early kdump, the new initramfs +size will become large, because it will put the vmlinuz and kdump initramfs into +the new initramfs.
+Next up, we need to add "rd.earlykdump" to enable early kdump in grub. After +making said changes, reboot your system to take effect. Of course, if you want +to disable early kdump, you can simply remove "rd.earlykdump" from kernel boot +parameters in grub, and reboot system like above.
+Once the boot is completed, you can check the status of the early kdump support +on the command prompt:
- # journalctl -x|grep early-kdump
+Then, you will see some useful logs, for exapmle:
+1. if early kdump is successful. +Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: early-kdump is enabled. +Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: kexec: loaded early- +kdump kernel
+2. if early kdump is disabled. +Mar 09 10:02:47 localhost.localdomain dracut-cmdline[189]: early-kdump is disabled.
+Limitation
+At present, early kdump doesn't support fadump. diff --git a/kexec-tools.spec b/kexec-tools.spec index f04527c..303b971 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -29,6 +29,7 @@ Source24: kdump-lib-initramfs.sh Source25: kdump.sysconfig.ppc64le Source26: kdumpctl.8 Source27: live-image-kdump-howto.txt +Source28: early-kdump-howto.txt
####################################### # These are sources for mkdumpramfs @@ -42,6 +43,8 @@ Source104: dracut-kdump-emergency.service Source105: dracut-kdump-error-handler.service Source106: dracut-kdump-capture.service Source107: dracut-kdump-emergency.target +Source108: dracut-early-kdump.sh +Source109: dracut-early-kdump-module-setup.sh
Requires(post): systemd-units Requires(preun): systemd-units @@ -136,6 +139,7 @@ rm -f kexec-tools.spec.in cp %{SOURCE10} . cp %{SOURCE21} . cp %{SOURCE27} . +cp %{SOURCE28} .
make %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64 @@ -194,6 +198,7 @@ make -C kdump-anaconda-addon install DESTDIR=$RPM_BUILD_ROOT %find_lang kdump-anaconda-addon
%define remove_dracut_prefix() %(echo -n %1|sed 's/.*dracut-//g') +%define remove_dracut_early_kdump_prefix() %(echo -n %1|sed 's/.*dracut-early-kdump-//g')
# deal with dracut modules mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase @@ -207,6 +212,11 @@ cp %{SOURCE106} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpb cp %{SOURCE107} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE107}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}} +mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump +cp %{SOURCE108} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}} +cp %{SOURCE109} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}} +chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}} +chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}}
%define dracutlibdir %{_prefix}/lib/dracut @@ -305,6 +315,7 @@ done %license COPYING %doc TODO %doc kexec-kdump-howto.txt +%doc early-kdump-howto.txt %doc kdump-in-cluster-environment.txt %doc live-image-kdump-howto.txt %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64 -- 2.9.5 _______________________________________________ kexec mailing list -- kexec@lists.fedoraproject.org To unsubscribe send an email to kexec-leave@lists.fedoraproject.org
Thanks Dave