Hello everyone,
FAI always saves the whole dmesg output on softupdates. This results in
"errors"/unknown lines (error.log) even if those kernel messages were sent long
ago, but you probably already known about them and you don't want to be
disturbed by these old messages every time again. (Of course you can add more
"rules" to savelog.LAST.source, but you don't want to disable serious error
messages.)
So where did this lead us:
You could delete the whole kernel ringbuffer (dmesg -c) on every softupdate,
but then you have to search for old dmesg outputs in the FAI logs, instead of
just typing dmesg - not practical.
Our idea is to set a marker to the kernel ringbuffer (if you want to) and only
save the dmesg output since the last softupdate. An example implementation (for
FAI 3.4.7) is attached to this mail.
While implementing this feature we were wondering why subroutines:save_dmesg is
called twice (in two tasks) - the only explanation we had, that you have the
dmesg.log even if a later task fails, but this output would still be incomplete
(and possibly useless) if an event occurs a few seconds after saving the dmesg.
Comments welcome!
Best regards,
Manuel Hachtkemper
PS: Despite we think shortening the dmesg.log should be useful for most users
we could think of a hook for this feature, but therefor it would be useful to
make save_dmesg a task (and the information of previous actions would be
helpful, too).
--- fai.orig 2011-08-04 14:36:55.184052445 +0200
+++ fai 2011-08-04 14:21:15.000000000 +0200
@@ -303,6 +303,11 @@
export fai_rundate=$(date +'%Y%m%d_%H%M%S')
export LOGDIR=/var/log/fai/$HOSTNAME/$action-$fai_rundate
mkdir -p $LOGDIR
+
+ # keep information about previous symlink targets
+ previous_last_action_dir=$(readlink -nf $LOGDIR/../last-$action)
+ previous_last_dir=$(readlink -nf $LOGDIR/../last)
+
ln -snf $action-$fai_rundate $LOGDIR/../last-$action
ln -snf $action-$fai_rundate $LOGDIR/../last
fi
--- subroutines.orig 2011-08-04 14:37:48.073652791 +0200
+++ subroutines 2011-08-05 12:08:23.000000000 +0200
@@ -81,9 +81,35 @@
mount -o rw,remount $1
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+### BEGIN SUBROUTINE INFO
+# Provides-Var: none
+# Requires-Var: $FAI_ACTION $LOGDIR $previous_last_action
+# Short-Description: save dmesg output to $LOGDIR
+### END SUBROUTINE INFO
+
save_dmesg() {
- dmesg > $LOGDIR/dmesg.log
+ # set a marker to dmesg to only show messages since the last run
+ if [ "${DMESG_SHORTLOG:-0}" -eq 1 ]; then
+ if [ "$FAI_ACTION" = softupdate ]; then
+ dmesg_marker=${previous_last_action_dir##*/}
+ if ! dmesg | fgrep -q "$dmesg_marker"; then
+ unset dmesg_marker
+ fi
+ fi
+ fi
+
+ # if DMESG_SHORTLOG is unset, not equals 1, dmesg_marker not
+ # availabe or FAI_ACTION is not softupdate save the whole output of dmesg
+ if [ -z "$dmesg_marker" ]; then
+ dmesg
+ else
+ dmesg | sed -e "1,/$dmesg_marker/d"
+ fi > $LOGDIR/dmesg.log
+
+ if [ "${DMESG_SHORTLOG:-0}" -eq 1 ]; then
+ echo FAI marker: "${LOGDIR##*/}" > /dev/kmsg
+ fi
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
umount_csspace() {
@@ -497,8 +523,6 @@
echo $$ > $stamp
- save_dmesg
-
task partition
task mountdisks
task extrbase
@@ -513,7 +537,7 @@
task chboot
rm -f $stamp
- save_dmesg # save again, because new messages could be created
+ save_dmesg
task savelog
if [ -f $stamp ]; then
@@ -609,7 +633,6 @@
[ -f /var/lib/fai/disk_var.sh ] && cp -p /var/lib/fai/disk_var.sh $LOGDIR
defnop wait_for_jobs
- save_dmesg
task mirror
task debconf
@@ -620,7 +643,6 @@
[ -f /proc/uptime ] && echo "The $FAI_ACTION took $[$(cut -d . -f 1 /proc/uptime)-$start_seconds] seconds."
rm -f $stamp
- # save again, because new messages could be created
save_dmesg
task savelog
umount_csspace
