devstack/lib/lvm
Daniel Genin d470867f08 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
2015-01-19 11:51:16 -05:00

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# 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: