kexec-tools/dracut-kdump.sh
Xunlei Pang 74c6f46429 Support special mount information via "dracut_args"
There are some complaints about nfs kdump that users must mount
nfs beforehand, which may cause some overhead to nfs server.
For example, there're thounsands of diskless clients deployed with
nfs dumping, each time the client is boot up, it will trigger
kdump rebuilding so will mount nfs, thus resulting in thousands
of nfs request concurrently imposed on the same nfs server.

We introduce a new way of specifying mount information via the
already-existent "dracut_args" directive(so avoid adding extra
directives in /etc/kdump.conf), we will skip all the filesystem
mounting and checking stuff for it. So it can be used in the
above-mentioned nfs scenario to avoid severe nfs server overhead.

Specifically, if there is any "--mount" information specified via
"dracut_args" in /etc/kdump.conf, always use it as the final mount
without any validation(mounting or checking like mount options,
fs size, etc), so users are expected to ensure its correctness.

NOTE:
-Only one mount target is allowed using "dracut_args" globally.
-Dracut will create <mountpoint> if it doesn't exist in kdump kernel,
 <mountpoint> must be specified as an absolute path.
-Users should do a test first and ensure it works because kdump does
 not prepare the mount or check all the validity.

Reviewed-by: Pratyush Anand <panand@redhat.com>
Suggested-by: Dave Young <dyoung@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
2016-08-26 14:03:48 +08:00

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#!/bin/sh
# continue here only if we have to save dump.
if [ -f /etc/fadump.initramfs ] && [ ! -f /proc/device-tree/rtas/ibm,kernel-dump ]; then
exit 0
fi
exec &> /dev/console
. /lib/dracut-lib.sh
. /lib/kdump-lib-initramfs.sh
set -o pipefail
DUMP_RETVAL=0
export PATH=$PATH:$KDUMP_SCRIPT_DIR
do_dump()
{
local _ret
eval $DUMP_INSTRUCTION
_ret=$?
if [ $_ret -ne 0 ]; then
echo "kdump: saving vmcore failed"
fi
return $_ret
}
do_kdump_pre()
{
if [ -n "$KDUMP_PRE" ]; then
"$KDUMP_PRE"
fi
}
do_kdump_post()
{
if [ -n "$KDUMP_POST" ]; then
"$KDUMP_POST" "$1"
fi
}
add_dump_code()
{
DUMP_INSTRUCTION=$1
}
dump_raw()
{
local _raw=$1
[ -b "$_raw" ] || return 1
echo "kdump: saving to raw disk $_raw"
if ! $(echo -n $CORE_COLLECTOR|grep -q makedumpfile); then
_src_size=`ls -l /proc/vmcore | cut -d' ' -f5`
_src_size_mb=$(($_src_size / 1048576))
monitor_dd_progress $_src_size_mb &
fi
echo "kdump: saving vmcore"
$CORE_COLLECTOR /proc/vmcore | dd of=$_raw bs=$DD_BLKSIZE >> /tmp/dd_progress_file 2>&1 || return 1
sync
echo "kdump: saving vmcore complete"
return 0
}
dump_ssh()
{
local _opt="-i $1 -o BatchMode=yes -o StrictHostKeyChecking=yes"
local _dir="$KDUMP_PATH/$HOST_IP-$DATEDIR"
local _host=$2
echo "kdump: saving to $_host:$_dir"
cat /var/lib/random-seed > /dev/urandom
ssh -q $_opt $_host mkdir -p $_dir || return 1
save_vmcore_dmesg_ssh ${DMESG_COLLECTOR} ${_dir} "${_opt}" $_host
echo "kdump: saving vmcore"
if [ "${CORE_COLLECTOR%%[[:blank:]]*}" = "scp" ]; then
scp -q $_opt /proc/vmcore "$_host:$_dir/vmcore-incomplete" || return 1
ssh $_opt $_host "mv $_dir/vmcore-incomplete $_dir/vmcore" || return 1
else
$CORE_COLLECTOR /proc/vmcore | ssh $_opt $_host "dd bs=512 of=$_dir/vmcore-incomplete" || return 1
ssh $_opt $_host "mv $_dir/vmcore-incomplete $_dir/vmcore.flat" || return 1
fi
echo "kdump: saving vmcore complete"
return 0
}
save_vmcore_dmesg_ssh() {
local _dmesg_collector=$1
local _path=$2
local _opts="$3"
local _location=$4
echo "kdump: saving vmcore-dmesg.txt"
$_dmesg_collector /proc/vmcore | ssh $_opts $_location "dd of=$_path/vmcore-dmesg-incomplete.txt"
_exitcode=$?
if [ $_exitcode -eq 0 ]; then
ssh -q $_opts $_location mv $_path/vmcore-dmesg-incomplete.txt $_path/vmcore-dmesg.txt
echo "kdump: saving vmcore-dmesg.txt complete"
else
echo "kdump: saving vmcore-dmesg.txt failed"
fi
}
get_host_ip()
{
local _host
if is_nfs_dump_target || is_ssh_dump_target
then
kdumpnic=$(getarg kdumpnic=)
[ -z "$kdumpnic" ] && echo "kdump: failed to get kdumpnic!" && return 1
_host=`ip addr show dev $kdumpnic|grep '[ ]*inet'`
[ $? -ne 0 ] && echo "kdump: wrong kdumpnic: $kdumpnic" && return 1
_host=`echo $_host | head -n 1 | cut -d' ' -f2`
_host="${_host%%/*}"
[ -z "$_host" ] && echo "kdump: wrong kdumpnic: $kdumpnic" && return 1
HOST_IP=$_host
fi
return 0
}
read_kdump_conf()
{
if [ ! -f "$KDUMP_CONF" ]; then
echo "kdump: $KDUMP_CONF not found"
return
fi
get_kdump_confs
# rescan for add code for dump target
while read config_opt config_val;
do
# remove inline comments after the end of a directive.
config_val=$(strip_comments $config_val)
case "$config_opt" in
dracut_args)
config_val=$(get_dracut_args_target "$config_val")
[[ -n "$config_val" ]] && add_dump_code "dump_fs $config_val"
;;
ext[234]|xfs|btrfs|minix|nfs)
add_dump_code "dump_fs $config_val"
;;
raw)
add_dump_code "dump_raw $config_val"
;;
ssh)
add_dump_code "dump_ssh $SSH_KEY_LOCATION $config_val"
;;
esac
done < $KDUMP_CONF
}
fence_kdump_notify()
{
if [ -n "$FENCE_KDUMP_NODES" ]; then
$FENCE_KDUMP_SEND $FENCE_KDUMP_ARGS $FENCE_KDUMP_NODES &
fi
}
read_kdump_conf
fence_kdump_notify
get_host_ip
if [ $? -ne 0 ]; then
echo "kdump: get_host_ip exited with non-zero status!"
exit 1
fi
if [ -z "$DUMP_INSTRUCTION" ]; then
add_dump_code "dump_fs $NEWROOT"
fi
do_kdump_pre
if [ $? -ne 0 ]; then
echo "kdump: kdump_pre script exited with non-zero status!"
do_final_action
fi
make_trace_mem "kdump saving vmcore" '1:shortmem' '2+:mem' '3+:slab'
do_dump
DUMP_RETVAL=$?
do_kdump_post $DUMP_RETVAL
if [ $? -ne 0 ]; then
echo "kdump: kdump_post script exited with non-zero status!"
fi
if [ $DUMP_RETVAL -ne 0 ]; then
exit 1
fi
do_final_action