lib/lvm

#!/bin/bash
#
# 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


# Functions
# ---------

# _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 $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 the lvmetad and tgtd services
    if is_fedora || is_suse; then
        # services is not started by default
        start_service lvm2-lvmetad
        start_service tgtd
    fi

    # Start with a clean volume group
    _create_lvm_volume_group $vg $size

    # 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
}

# Sentinal value to ensure that init of default lvm volume group is
# only performed once across calls of init_default_lvm_volume_group.
_DEFAULT_LVM_INIT=${_DEFAULT_LVM_INIT:-0}

# init_default_lvm_volume_group() initializes a default volume group
# intended to be shared between cinder and nova.  It is idempotent;
# the init of the default volume group is guaranteed to be performed
# only once so that either or both of the dependent services can
# safely call this function.
#
# Usage: init_default_lvm_volume_group()
function init_default_lvm_volume_group {
    if [[ "$_DEFAULT_LVM_INIT" = "0" ]]; then
        init_lvm_volume_group $DEFAULT_VOLUME_GROUP_NAME $VOLUME_BACKING_FILE_SIZE
        _DEFAULT_LVM_INIT=1
    fi
}

# set_lvm_filter() Gather all devices configured for LVM and
# use them to build a global device filter
# set_lvm_filter() Create a device filter
# and add to /etc/lvm.conf.  Note this uses
# all current PV's in use by LVM on the
# system to build it's filter.
#
# Usage: set_lvm_filter()
function set_lvm_filter {
    local filter_suffix='"r|.*|" ]'
    local filter_string="global_filter = [ "
    local pv
    local vg
    local line

    for pv_info in $(sudo pvs --noheadings -o name); do
        pv=$(echo -e "${pv_info}" | sed 's/ //g' | sed 's/\/dev\///g')
        new="\"a|$pv|\", "
        filter_string=$filter_string$new
    done
    filter_string=$filter_string$filter_suffix

    sudo sed -i "/# global_filter = \[*\]/a\    $global_filter$filter_string" /etc/lvm/lvm.conf
    echo_summary "set lvm.conf device global_filter to: $filter_string"
}

# Restore xtrace
$MY_XTRACE

# mode: shell-script
# End: