On Thu, Mar 28, 2019 at 6:55 AM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
-----Original Messages----- From: "Benjamin Hauger" hauger@noao.edu Sent Time: 2019-03-28 01:31:40 (Thursday) To: wuzhouhui wuzhouhui14@mails.ucas.ac.cn, centos@centos.org Cc: Subject: Re: [CentOS] How to specify kernel version when restart kdump
What do you mean? Wouldn't the kernel version always be the actual running version of the kernel that was booted?
Suppose the running kernel is 2.6.32, and then I installed kernel 3.10.0. The files under /boot includes (exclude some unimportant files): initramfs-2.6.32.img initramfs-3.10.0.img vmlinuz-2.6.32 vmlinuz-3.10.0 initrd-2.6.32kdump.img We can see that there is no initrd-3.10.0kdump.img for newly installed kernel 3.10.0, and kdump will generate initrd-3.10.0kdump.img only when booted as kernel 3.10.0. However, I want kdump to generate initrd-3.10.0kdump.img now (the current running kernel is 2.6.32).
Your particolar versions seem quite strange because 2.6.32 lets me think about CentOS 6 and 3.10.0 lets me think about CentOS 7. Any way see below for some discussion, not tried by me, so in case please use on test system before.
1) In CentOS 6 we have the classical SysV service file: /etc/rc.d/init.d/kdump
Supposing you have just installed 2.6.32-642.13.1.el6.x86_64 kernel
Analyzing what it runs we have
DUMP_KERNELVER="" MKDUMPRD_ARGS=""
. /etc/sysconfig/kdump In my case: KDUMP_BOOTDIR="/boot"
local running_kernel=`uname -r` kdump_kver=`echo $running_kernel | sed 's/smp//g'` MKDUMPRD="/sbin/mkdumprd -d -f $MKDUMPRD_ARGS"
kdump_initrd="${KDUMP_BOOTDIR}/initrd-${kdump_kver}kdump.img"
and at the end it runs this command if it doesn't find one: $MKDUMPRD $kdump_initrd $kdump_kver
that tipically will translate in:
/sbin/mkdumprd -d -f "/boot/initrd-2.6.32-642.13.1.el6.x86_64kdump.img"
2) In CentOS 7 we have systemd unit files and for kdump: /usr/lib/systemd/system/kdump.service
Supposing you have just installed 3.10.0-693.21.1.el7.x86_64
The script called actually it is /usr/bin/kdumpctl
See also fadump (firmware assisted dump) concepts in RHEL 7 / CentOS 7: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/htm...
But I think you are x86_64 so kdump sttill applies In kdumpctl we have something like this:
MKDUMPRD="/sbin/mkdumprd -f" TARGET_INITRD=""
. /lib/kdump/kdump-lib.sh
. /etc/sysconfig/kdump
eval $(cat /proc/cmdline| grep "BOOT_IMAGE" | cut -d' ' -f1) KDUMP_BOOTDIR="/boot"$(dirname $BOOT_IMAGE)
kdump_kver=`uname -r` TARGET_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img"
rebuild_kdump_initrd() { $MKDUMPRD $TARGET_INITRD $kdump_kver if [ $? != 0 ]; then echo "mkdumprd: failed to make kdump initrd" >&2 return 1 fi
return 0 }
So at the end the command will be:
$MKDUMPRD $TARGET_INITRD $kdump_kver
that in general should be something like this if you want to compile for kernel 3.10.0-693.21.1.el7.x86_64 :
/sbin/mkdumprd -f /boot/initramfs-3.10.0-693.21.1.el7.x86_64kdump.img 3.10.0-693.21.1.el7.x86_64
HIH trying, Gianluca