On 2016/05/24 at 17:34, Dave Young wrote:
Hi, Xunlei
On 05/23/16 at 03:06pm, Xunlei Pang wrote:
> 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 clients deployed with kdump
> diskless boot, 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.
>
> As an example:
> dracut_args --mount "192.168.1.1:/test test nfs defaults"
>
> NOTE:
> -Only one mount information is allowed using "dracut_args".
> -Dracut will create <mountpoint> if it doesn't exist in kdump kernel.
> -Users should do a test first and ensure it works because kdump does
> not prepare the mount and check all the validity.
>
> Suggested-by: Dave Young <dyoung(a)redhat.com>
> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
> ---
> dracut-kdump.sh | 6 +++++-
> dracut-module-setup.sh | 6 ++++++
> kdump-lib.sh | 31 ++++++++++++++++++++++++++++++-
> kdumpctl | 13 ++++++++++++-
> mkdumprd | 5 +++++
> 5 files changed, 58 insertions(+), 3 deletions(-)
>
> diff --git a/dracut-kdump.sh b/dracut-kdump.sh
> index 4aab205..c5bd4a6 100755
> --- a/dracut-kdump.sh
> +++ b/dracut-kdump.sh
> @@ -117,7 +117,7 @@ save_vmcore_dmesg_ssh() {
> get_host_ip()
> {
> local _host
> - if is_nfs_dump_target || is_ssh_dump_target
> + if is_nfs_dump_target || is_ssh_dump_target || dracut_args_contains_nfsmount
> then
> kdumpnic=$(getarg kdumpnic=)
> [ -z "$kdumpnic" ] && echo "kdump: failed to get
kdumpnic!" && return 1
> @@ -146,6 +146,10 @@ read_kdump_conf()
> # remove inline comments after the end of a directive.
> config_val=$(strip_comments $config_val)
> case "$config_opt" in
> + dracut_args)
> + config_val=$(get_target_from_dracut_args_val "$config_val")
> + [[ -n "$config_val" ]] && add_dump_code "dump_fs
$config_val"
> + ;;
> ext[234]|xfs|btrfs|minix|nfs)
> add_dump_code "dump_fs $config_val"
> ;;
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 4cd7107..a95e87b 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -433,6 +433,11 @@ kdump_install_conf() {
> ssh|nfs)
> kdump_install_net "$config_val"
> ;;
> + dracut_args)
> + if [[ $(get_fstype_from_dracut_args_val "$config_val") = nfs*
]]; then
> + kdump_install_net "$(get_target_from_dracut_args_val
"$config_val")"
> + fi
> + ;;
> kdump_pre|kdump_post|extra_bins)
> dracut_install $config_val
> ;;
> @@ -684,6 +689,7 @@ install() {
> inst "/bin/date" "/bin/date"
> inst "/bin/sync" "/bin/sync"
> inst "/bin/cut" "/bin/cut"
> + inst "/usr/bin/awk" "/usr/bin/awk"
Can we avoid installing extra tools like awk, if it is for getting the fs type from
fstab line, we can do similar thing as dracut modules.d/95fstab-sys/mount-sys.sh:
read _dev _mp _fs _opts < $1
Or using cut:
echo $1|tr -s [:blank:]|cut -d' ' -f3
Suppose $a is the line with --mount in /etc/kdump.conf
_fstab=$(echo ${a#*--mount})
Sure
> inst "/bin/head" "/bin/head"
> inst "/sbin/makedumpfile" "/sbin/makedumpfile"
> inst "/sbin/vmcore-dmesg" "/sbin/vmcore-dmesg"
> diff --git a/kdump-lib.sh b/kdump-lib.sh
> index fc2c036..39a2d00 100755
> --- a/kdump-lib.sh
> +++ b/kdump-lib.sh
> @@ -45,7 +45,8 @@ is_fs_dump_target()
>
> is_user_configured_dump_target()
> {
> - return $(is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target ||
is_fs_dump_target)
> + return $(dracut_args_contains_mount || is_ssh_dump_target || is_nfs_dump_target
|| \
> + is_raw_dump_target || is_fs_dump_target)
> }
>
> strip_comments()
> @@ -279,3 +280,31 @@ is_hostname()
> fi
> echo $1 | grep -q "[a-zA-Z]"
> }
> +
> +# If "dracut_args" contains "--mount" information, use it
> +# directly without any check(users are expected to ensure
> +# its correctness).
> +dracut_args_contains_mount()
> +{
> + return $(grep ^dracut_args /etc/kdump.conf | grep -q "\-\-mount")
> +}
> +
> +dracut_args_contains_nfsmount()
> +{
> + local config_val
> +
> + config_val=$(grep ^dracut_args /etc/kdump.conf | awk -F "--mount
\"" '{print $2}' | cut -d' ' -f3)
> + [[ $config_val = nfs* ]] && return 0
> +
> + return 1
> +}
> +
> +get_fstype_from_dracut_args_val()
> +{
> + echo $1 | awk -F "--mount \"" '{print $2}' | cut -d'
' -f3
> +}
> +
> +get_target_from_dracut_args_val()
> +{
> + echo $1 | awk -F "--mount \"" '{print $2}' | cut -d'
' -f1
> +}
> diff --git a/kdumpctl b/kdumpctl
> index fcc9ad0..aa8232c 100755
> --- a/kdumpctl
> +++ b/kdumpctl
> @@ -236,12 +236,18 @@ check_config()
> {
> local nr
>
> - nr=$(awk 'BEGIN{cnt=0}
/^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix/{cnt++} END{print cnt}'
$KDUMP_CONFIG_FILE)
> + nr=$(awk 'BEGIN{cnt=0}
/^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix|^dracut_args .*\-\-mount/{cnt++}
END{print cnt}' $KDUMP_CONFIG_FILE)
> [ $nr -gt 1 ] && {
> echo "More than one dump targets specified."
> return 1
> }
>
> + nr=$(grep "^dracut_args .*\-\-mount" $KDUMP_CONFIG_FILE | grep -o
"\-\-mount" | wc -l)
> + [ $nr -gt 1 ] && {
> + echo "More than one mount targets specified in
\"dracut_args\"."
> + return 1
> + }
> +
> while read config_opt config_val; do
> # remove inline comments after the end of a directive.
> config_val=$(strip_comments $config_val)
> @@ -365,6 +371,11 @@ check_dump_fs_modified()
> local _new_dev _new_mntpoint _new_fstype
> local _target _path _dracut_args
>
> + # No need to check in case of mount target specified via "dracut_args".
> + if dracut_args_contains_mount; then
> + return 0
> + fi
> +
> # No need to check in case of raw target.
> # Currently we do not check also if ssh/nfs target is specified
> if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target; then
> diff --git a/mkdumprd b/mkdumprd
> index 78afb1a..573da96 100644
> --- a/mkdumprd
> +++ b/mkdumprd
> @@ -544,6 +544,11 @@ do
> verify_core_collector "$config_val"
> ;;
> dracut_args)
> + if [[ $(get_fstype_from_dracut_args_val "$config_val") = nfs* ]];
then
is_nfs_in_dracut_args sounds better?
sounds good.
like get_fstype_from_dracut_args_vgl seems too long, how about something like:
get_dracut_args_fs;
get_dracut_args_target;
...
I'm fine with this.
Regards,
Xunlei
> + add_dracut_module "nfs"
> + # nfs may not be mounted, we need to add nfs related modules
explicitly.
> + add_dracut_arg "--add-drivers" "nfs nfsv4"
> + fi
> add_dracut_arg $config_val
> ;;
> *)
> --
> 1.8.3.1
>
Thanks
Dave