Patchwork [v6,2/2] qemu-ga: sample fsfreeze hooks

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Submitter Tomoki Sekiyama
Date Nov. 30, 2012, 1:33 p.m.
Message ID <20121130133357.32478.6554.stgit@melchior2.sdl.hitachi.co.jp>
Download mbox | patch
Permalink /patch/202960/
State New
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Comments

Tomoki Sekiyama - Nov. 30, 2012, 1:33 p.m.
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 <tomoki.sekiyama.qu@hitachi.com>
---
 docs/qemu-guest-agent/fsfreeze-hook                |   33 ++++++++++++
 .../fsfreeze-hook.d.sample/mysql-flush.sh          |   55 ++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100755 docs/qemu-guest-agent/fsfreeze-hook
 create mode 100755 docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
Luiz Capitulino - Dec. 4, 2012, 4:51 p.m.
On Fri, 30 Nov 2012 22:33:57 +0900
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> 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 <tomoki.sekiyama.qu@hitachi.com>
> ---
>  docs/qemu-guest-agent/fsfreeze-hook                |   33 ++++++++++++
>  .../fsfreeze-hook.d.sample/mysql-flush.sh          |   55 ++++++++++++++++++++
>  2 files changed, 88 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..ed7d86d
> --- /dev/null
> +++ b/docs/qemu-guest-agent/fsfreeze-hook
> @@ -0,0 +1,33 @@
> +#!/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

The script you introduce is called fsfreeze-hook.d.sample. If it's expected
that people really use these two scripts (vs. doc purposes only) I suggest
the following:

 1. Move these files to scripts/
 2. Drop the .sample suffix

> +
> +# 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" >>$LOGFILE
> +done
> +
> +exit 0
> diff --git a/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
> new file mode 100755
> index 0000000..611215e
> --- /dev/null
> +++ b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
> @@ -0,0 +1,55 @@
> +#!/bin/sh
> +
> +# Flush MySQL tables to the disk before the filesystem is freezed.
> +# At the same time, this keeps a read lock while the filesystem is freezed
> +# in order to avoid write accesses by the other clients.
> +
> +MYSQL="/usr/bin/mysql"
> +MYSQL_OPTS="-uroot" #"-prootpassword"
> +FIFO=/tmp/mysql-flush.fifo
> +MYSQL_CMD="$MYSQL $MYSQL_OPTS"
> +
> +# Check mysql is installed and the server running
> +[ -x $MYSQL ] && $MYSQL_CMD < /dev/null || exit 0
> +
> +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 | $MYSQL_CMD &
> +        # wait until every block is flushed
> +        while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\
> +                 $MYSQL_CMD | tail -1 | cut -f 2)" -gt 0 ]; do
> +            sleep 1
> +        done
> +        # for InnoDB, wait until every log is flushed
> +        INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX)
> +        [ $? -ne 0 ] && exit 2
> +        trap "rm -f $INNODB_STATUS" SIGINT
> +        while :; do
> +            printf "SHOW ENGINE INNODB STATUS \\G" | $MYSQL_CMD > $INNODB_STATUS
> +            LOG_CURRENT=$(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 $FIFO
> +        ;;
> +
> +    *)
> +        exit 1
> +        ;;
> +esac
>
Tomoki Sekiyama - Dec. 5, 2012, 8:41 a.m.
On 2012/12/05 1:51, Luiz Capitulino wrote:
> On Fri, 30 Nov 2012 22:33:57 +0900
> Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:
> 
>> Adds sample hook scripts for --fsfreeze-hook option of qemu-ga.
>>   - fsfreeze-hook : execute scripts in fsfreeze-hook.d/
>>   - fsfreeze-hook.d.sample/mysql-flush.sh : quiesce MySQL before snapshot
>>
>> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
>> ---
>>  docs/qemu-guest-agent/fsfreeze-hook                |   33 ++++++++++++
>>  .../fsfreeze-hook.d.sample/mysql-flush.sh          |   55 ++++++++++++++++++++
>>  2 files changed, 88 insertions(+)
>>  create mode 100755 docs/qemu-guest-agent/fsfreeze-hook
>>  create mode 100755 docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
>>
>> diff --git a/docs/qemu-guest-agent/fsfreeze-hook b/docs/qemu-guest-agent/fsfreeze-hook
>> new file mode 100755
>> index 0000000..ed7d86d
>> --- /dev/null
>> +++ b/docs/qemu-guest-agent/fsfreeze-hook
>> @@ -0,0 +1,33 @@
>> +#!/bin/sh
>> +
>> +# This script is executed when a guest agent receives fsfreeze-freeze and
>> +# fsfreeze-thaw command, if it is specified in --fsfreeze-hook (-F)
>> +# option of qemu-ga or placed in default path (/etc/qemu/fsfreeze-hook).
>> +# When the agent receives fsfreeze-freeze request, this script is issued with
>> +# "freeze" argument before the filesystem is freezed. And for fsfreeze-thaw
>> +# request, it is issued with "thaw" argument after filesystem is thawed.
>> +
>> +LOGFILE=/var/log/qga-fsfreeze-hook.log
>> +FSFREEZE_D=$(dirname -- "$0")/fsfreeze-hook.d
> 
> The script you introduce is called fsfreeze-hook.d.sample. If it's expected
> that people really use these two scripts (vs. doc purposes only) I suggest
> the following:
> 
>  1. Move these files to scripts/
>  2. Drop the .sample suffix

It is good for "fsfreeze-hook". But as for "mysql-flush.sh", users may
need to configure authentication etc. if their environments are with
non-default setup (by edditing either the script or ~/.my.cnf file).

So, I'd like to (1)move these files to scripts/, but (2)reamin .sample
suffix to indicate that users may need to modify the script.
How do you think?

Thanks,
Luiz Capitulino - Dec. 5, 2012, 11:49 a.m.
On Wed, 05 Dec 2012 17:41:08 +0900
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:

> On 2012/12/05 1:51, Luiz Capitulino wrote:
> > On Fri, 30 Nov 2012 22:33:57 +0900
> > Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> 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 <tomoki.sekiyama.qu@hitachi.com>
> >> ---
> >>  docs/qemu-guest-agent/fsfreeze-hook                |   33 ++++++++++++
> >>  .../fsfreeze-hook.d.sample/mysql-flush.sh          |   55 ++++++++++++++++++++
> >>  2 files changed, 88 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..ed7d86d
> >> --- /dev/null
> >> +++ b/docs/qemu-guest-agent/fsfreeze-hook
> >> @@ -0,0 +1,33 @@
> >> +#!/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
> > 
> > The script you introduce is called fsfreeze-hook.d.sample. If it's expected
> > that people really use these two scripts (vs. doc purposes only) I suggest
> > the following:
> > 
> >  1. Move these files to scripts/
> >  2. Drop the .sample suffix
> 
> It is good for "fsfreeze-hook". But as for "mysql-flush.sh", users may
> need to configure authentication etc. if their environments are with
> non-default setup (by edditing either the script or ~/.my.cnf file).
> 
> So, I'd like to (1)move these files to scripts/, but (2)reamin .sample
> suffix to indicate that users may need to modify the script.
> How do you think?

You could add the '.sample' suffix to the mysql script and add that
suffix to is_ignored_file().
Tomoki Sekiyama - Dec. 6, 2012, 3:10 a.m.
On 2012/12/05 20:49, Luiz Capitulino wrote:
> On Wed, 05 Dec 2012 17:41:08 +0900
> Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:
> 
>> On 2012/12/05 1:51, Luiz Capitulino wrote:
>>> On Fri, 30 Nov 2012 22:33:57 +0900
>>> Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> 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 <tomoki.sekiyama.qu@hitachi.com>
>>>> ---
>>>>  docs/qemu-guest-agent/fsfreeze-hook                |   33 ++++++++++++
>>>>  .../fsfreeze-hook.d.sample/mysql-flush.sh          |   55 ++++++++++++++++++++
>>>>  2 files changed, 88 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..ed7d86d
>>>> --- /dev/null
>>>> +++ b/docs/qemu-guest-agent/fsfreeze-hook
>>>> @@ -0,0 +1,33 @@
>>>> +#!/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
>>>
>>> The script you introduce is called fsfreeze-hook.d.sample. If it's expected
>>> that people really use these two scripts (vs. doc purposes only) I suggest
>>> the following:
>>>
>>>  1. Move these files to scripts/
>>>  2. Drop the .sample suffix
>>
>> It is good for "fsfreeze-hook". But as for "mysql-flush.sh", users may
>> need to configure authentication etc. if their environments are with
>> non-default setup (by edditing either the script or ~/.my.cnf file).
>>
>> So, I'd like to (1)move these files to scripts/, but (2)reamin .sample
>> suffix to indicate that users may need to modify the script.
>> How do you think?
> 
> You could add the '.sample' suffix to the mysql script and add that
> suffix to is_ignored_file().
> 

Okey, I will try this in the next version.
(It seems Makefile also needs a patch to treat directry named "*.d".)

Thanks,

Patch

diff --git a/docs/qemu-guest-agent/fsfreeze-hook b/docs/qemu-guest-agent/fsfreeze-hook
new file mode 100755
index 0000000..ed7d86d
--- /dev/null
+++ b/docs/qemu-guest-agent/fsfreeze-hook
@@ -0,0 +1,33 @@ 
+#!/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" >>$LOGFILE
+done
+
+exit 0
diff --git a/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
new file mode 100755
index 0000000..611215e
--- /dev/null
+++ b/docs/qemu-guest-agent/fsfreeze-hook.d.sample/mysql-flush.sh
@@ -0,0 +1,55 @@ 
+#!/bin/sh
+
+# Flush MySQL tables to the disk before the filesystem is freezed.
+# At the same time, this keeps a read lock while the filesystem is freezed
+# in order to avoid write accesses by the other clients.
+
+MYSQL="/usr/bin/mysql"
+MYSQL_OPTS="-uroot" #"-prootpassword"
+FIFO=/tmp/mysql-flush.fifo
+MYSQL_CMD="$MYSQL $MYSQL_OPTS"
+
+# Check mysql is installed and the server running
+[ -x $MYSQL ] && $MYSQL_CMD < /dev/null || exit 0
+
+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 | $MYSQL_CMD &
+        # wait until every block is flushed
+        while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\
+                 $MYSQL_CMD | tail -1 | cut -f 2)" -gt 0 ]; do
+            sleep 1
+        done
+        # for InnoDB, wait until every log is flushed
+        INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX)
+        [ $? -ne 0 ] && exit 2
+        trap "rm -f $INNODB_STATUS" SIGINT
+        while :; do
+            printf "SHOW ENGINE INNODB STATUS \\G" | $MYSQL_CMD > $INNODB_STATUS
+            LOG_CURRENT=$(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
+        ;;
+
+    *)
+        exit 1
+        ;;
+esac