create rbd snap from instance disk

diff --git a/rbd-snap-backup.sh b/rbd-snap-backup.sh
new file mode 100755 (executable)
index 0000000..ed57fd8
--- /dev/null
+++ b/rbd-snap-backup.sh
@@ -0,0 +1,41 @@
+#!/bin/sh -xe
+
+instance=$1
+disk=$2
+
+test -z "$1" -o -z "$2" && echo "Usage: $0 instance disk" && exit 1
+
+rbd_image=`gnt-instance info --static $instance | grep logical_id: | cut -d\' -f4 | grep "\.rbd\.disk$disk\$"`
+
+test -z "$rbd_image" && echo "can't find rbd_image name for $instance $disk" && exit 1
+
+rbd snap add     $rbd_image@backup
+rbd snap protect $rbd_image@backup
+
+rbd clone        $rbd_image@backup backup-$instance-$disk
+
+rbd_dev=`rbd map backup-$instance-$disk`
+
+mkdir /dev/shm/$rbd_image.snap
+
+# FIXME: test does offset work
+# we must mount filesystem read-write to allow journal recovery
+#offset=\`fdisk -l $rbd_dev -u | grep Linux$ | grep $rbd_dev | head -1 | sed 's/\*/ /' | awk '{ print \$2 * 512 }'\`
+#test ! -z "\$offset" && offset=",offset=\$offset"
+#mount $rbd_dev /dev/shm/\$rbd_image.snap -o noatime\$offset
+mount $rbd_dev /dev/shm/$rbd_image.snap -o noatime$offset
+
+# execute something on mounted filesystem
+read -p "wait for key" key
+
+
+umount /dev/shm/$rbd_image.snap
+
+rbd unmap backup-$instance-$disk
+rbd rm    backup-$instance-$disk
+
+rbd snap unprotect $rbd_image@backup
+rbd snap rm        $rbd_image@backup
+
+rmdir /dev/shm/$rbd_image.snap
+