Adds support for LVM ephemeral storage in Nova
DevStack currently lacks support for LVM ephemeral storage in Nova.
This support is important for testing of Nova's LVM backend. The
proposed change adds a default volume group, to be shared by Cinder
and Nova. It also adds a configuration option NOVA_BACKEND, which
must be LVM if it is set, that determines whether Nova should be
configured to use LVM ephemeral storage.
Change-Id: I4eb9afff3536fbcd563939f2d325efbb845081bb
diff --git a/lib/lvm b/lib/lvm
new file mode 100644
index 0000000..4ef260d
--- /dev/null
+++ b/lib/lvm
@@ -0,0 +1,124 @@
+# lib/lvm
+# Configure the default LVM volume group used by Cinder and Nova
+
+# Dependencies:
+#
+# - ``functions`` file
+# - ``cinder`` configurations
+
+# DATA_DIR
+
+# clean_default_volume_group - called from clean()
+# configure_default_volume_group - called from configure()
+# init_default_volume_group - called from init()
+
+
+# Save trace setting
+MY_XTRACE=$(set +o | grep xtrace)
+set +o xtrace
+
+
+# Defaults
+# --------
+# Name of the lvm volume groups to use/create for iscsi volumes
+# This monkey-motion is for compatibility with icehouse-generation Grenade
+# If ``VOLUME_GROUP`` is set, use it, otherwise we'll build a VG name based
+# on ``VOLUME_GROUP_NAME`` that includes the backend name
+# Grenade doesn't use ``VOLUME_GROUP2`` so it is left out
+VOLUME_GROUP_NAME=${VOLUME_GROUP:-${VOLUME_GROUP_NAME:-stack-volumes}}
+DEFAULT_VOLUME_GROUP_NAME=$VOLUME_GROUP_NAME-default
+
+# Backing file name is of the form $VOLUME_GROUP$BACKING_FILE_SUFFIX
+BACKING_FILE_SUFFIX=-backing-file
+
+
+# Entry Points
+# ------------
+
+# _clean_lvm_volume_group removes all default LVM volumes
+#
+# Usage: clean_lvm_volume_group $vg
+function _clean_lvm_volume_group {
+ local vg=$1
+
+ # Clean out existing volumes
+ sudo lvremove -f $vg
+}
+
+# _clean_lvm_backing_file() removes the backing file of the
+# volume group
+#
+# Usage: _clean_lvm_backing_file() $backing_file
+function _clean_lvm_backing_file {
+ local backing_file=$1
+
+ # if the backing physical device is a loop device, it was probably setup by devstack
+ if [[ -n "$backing_file" ]] && [[ -e "$backing_file" ]]; then
+ local vg_dev=$(sudo losetup -j $backing_file | awk -F':' '/'$BACKING_FILE_SUFFIX'/ { print $1}')
+ sudo losetup -d $vg_dev
+ rm -f $backing_file
+ fi
+}
+
+# clean_lvm_volume_group() cleans up the volume group and removes the
+# backing file
+#
+# Usage: clean_lvm_volume_group $vg
+function clean_lvm_volume_group {
+ local vg=$1
+
+ _clean_lvm_volume_group $vg
+ # if there is no logical volume left, it's safe to attempt a cleanup
+ # of the backing file
+ if [[ -z "$(sudo lvs --noheadings -o lv_name $vg 2>/dev/null)" ]]; then
+ _clean_lvm_backing_file $DATA_DIR/$vg$BACKING_FILE_SUFFIX
+ fi
+}
+
+
+# _create_volume_group creates default volume group
+#
+# Usage: _create_lvm_volume_group() $vg $size
+function _create_lvm_volume_group {
+ local vg=$1
+ local size=$2
+
+ local backing_file=$DATA_DIR/$vg$BACKING_FILE_SUFFIX
+ if ! sudo vgs $vg; then
+ # Only create if the file doesn't already exists
+ [[ -f $DATA_DIR/$backing_file ]] || truncate -s $size $backing_file
+ local vg_dev=`sudo losetup -f --show $backing_file`
+
+ # Only create volume group if it doesn't already exist
+ if ! sudo vgs $vg; then
+ sudo vgcreate $vg $vg_dev
+ fi
+ fi
+}
+
+# init_lvm_volume_group() initializes the volume group creating the backing
+# file if necessary
+#
+# Usage: init_lvm_volume_group() $vg
+function init_lvm_volume_group {
+ local vg=$1
+ local size=$2
+ # Start with a clean volume group
+ _create_lvm_volume_group $vg $size
+
+ if is_fedora || is_suse; then
+ # service is not started by default
+ start_service tgtd
+ fi
+
+ # Remove iscsi targets
+ sudo tgtadm --op show --mode target | grep Target | cut -f3 -d ' ' | sudo xargs -n1 tgt-admin --delete || true
+
+ _clean_lvm_volume_group $vg
+}
+
+# Restore xtrace
+$MY_XTRACE
+
+# mode: shell-script
+# End: