From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57948) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbZFt-0000Y1-C5 for qemu-devel@nongnu.org; Thu, 22 Nov 2012 11:03:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TbZFm-0005F8-6Y for qemu-devel@nongnu.org; Thu, 22 Nov 2012 11:03:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25920) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbZFl-0005Eq-Uv for qemu-devel@nongnu.org; Thu, 22 Nov 2012 11:03:50 -0500 Date: Thu, 22 Nov 2012 14:03:43 -0200 From: Luiz Capitulino Message-ID: <20121122140343.18a911fe@doriath.home> In-Reply-To: <20121122021549.9852.73727.stgit@melchior2.sdl.hitachi.co.jp> References: <20121122021535.9852.40353.stgit@melchior2.sdl.hitachi.co.jp> <20121122021549.9852.73727.stgit@melchior2.sdl.hitachi.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 2/2] qemu-ga: sample fsfreeze hooks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Tomoki Sekiyama Cc: qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com On Thu, 22 Nov 2012 11:15:49 +0900 Tomoki Sekiyama wrote: > Adds sample hook scripts for --fsfreeze-hook option of qemu-ga. > - fsfreeze-hook : execute scripts in fsfreeze-hook.d/ > - fsfreeze-hook.d.sample/mysql-flush.sh : quiesce MySQL before snapshot > > Signed-off-by: Tomoki Sekiyama > --- > docs/qemu-guest-agent/fsfreeze-hook | 31 +++++++++++++ > .../fsfreeze-hook.d.sample/mysql-flush.sh | 47 ++++++++++++++++++++ > 2 files changed, 78 insertions(+) > create mode 100755 docs/qemu-guest-agent/fsfreeze-hook > create mode 100755 docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh > > diff --git a/docs/qemu-guest-agent/fsfreeze-hook b/docs/qemu-guest-agent/fsfreeze-hook > new file mode 100755 > index 0000000..319f68c > --- /dev/null > +++ b/docs/qemu-guest-agent/fsfreeze-hook > @@ -0,0 +1,31 @@ > +#!/bin/sh > + > +# This script is executed when a guest agent receives fsfreeze-freeze and > +# fsfreeze-thaw command, if it is specified in --fsfreeze-hook (-F) > +# option of qemu-ga or placed in default path (/etc/qemu/fsfreeze-hook). > +# When the agent receives fsfreeze-freeze request, this script is issued with > +# "freeze" argument before the filesystem is freezed. And for fsfreeze-thaw > +# request, it is issued with "thaw" argument after filesystem is thawed. > + > +LOGFILE=/var/log/qga-fsfreeze-hook.log > +FSFREEZE_D=$(dirname -- "$0")/fsfreeze-hook.d > + > +# Check whether file $1 is a backup or rpm-generated file and should be ignored > +is_ignored_file() { > + case "$1" in > + *~ | *.bak | *.orig | *.rpmnew | *.rpmorig | *.rpmsave) > + return 0 ;; > + esac > + return 1 > +} > + > +# Iterate executables in directory "fsfreeze-hook.d" with the specified args > +[ ! -d "$FSFREEZE_D" ] && exit 1 > +for file in "$FSFREEZE_D"/* ; do > + is_ignored_file "$file" && continue > + [ -x "$file" ] || continue > + echo "$(date): execute $file $@" >>$LOGFILE > + "$file" "$@" >>$LOGFILE 2>&1 > + STATUS=$? > + echo "$(date): $file finished with status=$STATUS" >>$LOGFILE > +done execute_fsfreeze_hook() will fail the freeze process if this script fails. Two comments: 1. Do we want to fail the freeze process if one of the sub-scripts fails? If yes, then we have to exit 1 in the first failure 2. The exit status of the script will echo's exit status. I doubt we want that > diff --git a/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh > new file mode 100755 > index 0000000..e6d7998 > --- /dev/null > +++ b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh > @@ -0,0 +1,47 @@ > +#!/bin/sh > + > +# Flush MySQL tables to the disk before the filesystem is freezed. > +# At the same time, this keeps a read lock while the filesystem is freezed > +# in order to avoid write accesses by the other clients. > + > +MYSQL="mysql -uroot" #"-prootpassword" > +FIFO=/tmp/mysql-flush.fifo > + > +flush_and_wait() { > + printf "FLUSH TABLES WITH READ LOCK \\G\n" > + read < $FIFO > + printf "UNLOCK TABLES \\G\n" > +} > + > +case "$1" in > + freeze) > + mkfifo $FIFO || exit 1 > + flush_and_wait | $MYSQL & Honest question: what happens if I don't have mysql installed? > + # wait until every block is flushed > + while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\ > + $MYSQL | tail -1 | cut -f 2)" -gt 0 ]; do > + sleep 1 > + done > + # for InnoDB, wait until every log is flushed > + INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX) > + [ $? -ne 0 ] && exit 2 > + trap "rm -f $INNODB_STATUS" SIGINT > + while :; do > + printf "SHOW ENGINE INNODB STATUS \\G" | $MYSQL > $INNODB_STATUS > + LOG_CURRENT=$(grep 'Log sequence number' $INNODB_STATUS |\ > + tr -s ' ' | cut -d' ' -f4) > + LOG_FLUSHED=$(grep 'Log flushed up to' $INNODB_STATUS |\ > + tr -s ' ' | cut -d' ' -f5) > + [ "$LOG_CURRENT" = "$LOG_FLUSHED" ] && break > + sleep 1 > + done > + rm -f $INNODB_STATUS > + ;; > + > + thaw) > + [ ! -p $FIFO ] && exit 1 > + echo > $FIFO > + rm -f $FIFO > + ;; > +esac > + > >