[PATCH v2] kdumpctl: eliminate redundant lsinitrd in dracut

[Ziyue Yang]

Currently in Fedora/RedHat dracut installs its fedora.conf.example
as the default config file, in which sysloglvl is set 5. This leads
to maxloglvl=5 in dracut calls, making unnecessary lsinitrd calls
during initramfs builds.

This patch makes use of --conf and --confdir arguments of dracut,
creates temp config directory before mkdumprd(dracut) calls. It
appends sysloglvl=0 option by creating a 99-kdumpctl.conf file in
the temp config directory.

1) Before this patch
$ kdumpctl stop; touch /etc/kdump.conf; time kdumpctl start
kexec: unloaded kdump kernel
Stopping kdump: [OK]
Detected change(s) in the following file(s):
  /etc/kdump.conf
Rebuilding /boot/initramfs-4.10.10-200.fc25.x86_64kdump.img 4.10.10-200.fc25_x86_64
kexec: loaded kdump kernel
Starting kdump: [OK]
real    0m18.716s
user    0m13.863s
sys     0m3.269s

2) After this patch
$ kdumpctl stop; touch /etc/kdump.conf; time kdumpctl start
kexec: unloaded kdump kernel
Stopping kdump: [OK]
Detected change(s) in the following file(s):
  /etc/kdump.conf
Rebuilding /boot/initramfs-4.10.10-200.fc25.x86_64kdump.img 4.10.10-200.fc25_x86_64
kexec: loaded kdump kernel
Starting kdump: [OK]
real    0m13.665s
user    0m10.945s
sys     0m2.907s

Signed-off-by: Ziyue Yang <ziyang(a)redhat.com&gt;
---
 kdumpctl | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/kdumpctl b/kdumpctl
index 4d6b3e8..defd57e 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -5,7 +5,6 @@ KDUMP_KERNELVER=""
 KDUMP_COMMANDLINE=""
 KEXEC_ARGS=""
 KDUMP_CONFIG_FILE="/etc/kdump.conf"
-MKDUMPRD="/sbin/mkdumprd -f"
 SAVE_PATH=/var/crash
 SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
 INITRD_CHECKSUM_LOCATION="/boot/.fadump_initrd_checksum"
@@ -20,6 +19,18 @@ DEFAULT_DUMP_MODE="kdump"
 image_time=0
 
 [[ $dracutbasedir ]] || dracutbasedir=/usr/lib/dracut
+
+# lower dracut's default sysloglvl to speedup initramfs build
+DRACUT_SYSLOGLVL="2"
+# make temp dir for dracut conf files
+[[ $dracutconfdir ]] || dracutconfdir=/tmp/kdumpctl.dracut.conf
+mkdir -p $dracutconfdir/dracut.conf.d
+[[ -e $dracutbasedir/dracut.conf.d ]] && cp -rf $dracutbasedir/dracut.conf.d
$dracutconfdir/
+[[ -e $dracutbasedir/dracut.conf ]] && cp -rf $dracutbasedir/dracut.conf
$dracutconfdir/
+echo "sysloglvl=$DRACUT_SYSLOGLVL" >
$dracutconfdir/dracut.conf.d/99-kdumpctl.conf
+
+MKDUMPRD="/sbin/mkdumprd --conf $dracutconfdir/dracut.conf --confdir
$dracutconfdir/dracut.conf.d -f"
+
 . $dracutbasedir/dracut-functions.sh
 . /lib/kdump/kdump-lib.sh
 
@@ -284,6 +295,9 @@ rebuild_initrd()
 		rebuild_kdump_initrd
 	fi
 
+	# delete tmp conf folder for dracut
+	rm -rf /tmp/kdumpctl.dracut.conf
+
 	return $?
 }
 
-- 
2.9.3