diff --git a/cts/benchmark/clubench.in b/cts/benchmark/clubench.in
index 6adbe46cb0..e65b60d62c 100644
--- a/cts/benchmark/clubench.in
+++ b/cts/benchmark/clubench.in
@@ -1,190 +1,200 @@
 #!/bin/sh
 #
+# Copyright 2010-2021 the Pacemaker project contributors
+#
+# The version control history for this file may have further details.
+#
+# This source code is licensed under the GNU General Public License version 2
+# or later (GPLv2+) WITHOUT ANY WARRANTY.
 
 SSHOPTS="-l root -o PasswordAuthentication=no -o ConnectTimeout=5"
 
 msg() {
 	echo "$@" >&2
 }
 usage() {
 	echo "usage: $0 <dir>"
 	echo "	dir: working directory (with the control file)"
 	exit 0
 }
 
 [ $# -eq 0 ] && usage
 WORKDIR=$1
 test -d "$WORKDIR" || usage
 
 CTSCTRL=~/.cts
 CTRL=$WORKDIR/control
 CSV=$WORKDIR/bench.csv
 STATS=$WORKDIR/bench.stats
 
 test -f $CTRL && . $CTRL
 
 @datadir@/@PACKAGE@/tests/cts/cluster_test 500 || {
 	msg "cluster_test failed"
 	exit 1
 }
 
 test -f $CTSCTRL ||  {
 	msg no CTS control file $CTSCTRL
 	exit 1
 }
 . $CTSCTRL
 
 : ${CTS_logfacility:=local7}
 : ${CTS_stack:=corosync}
 : ${CTS_logfile:="@CRM_LOG_DIR@/ha-log-bench"}
 : ${CTS_adv:="--schema pacemaker-1.2 --clobber-cib -r"}
 : ${RUNS:=3}
 : ${CTSTESTS:="--benchmark"}
 : ${CTSDIR:="@datadir@/@PACKAGE@/tests/cts"}
+: ${CTS_node_list:=""}
+: ${CTS_boot:=""}
+: ${CTS_stonith:=""}
+: ${CTS_stonith_args:=""}
 
-[ "$CTS_node_list" ] || {
+[ -n "$CTS_node_list" ] || {
 	msg no node list specified
 	exit 1
 }
 
 case "$CTS_stack" in
 corosync) CRM_REPORT_OPTS="--corosync";;
 *) msg "$CTS_stack: cluster stack not recognized"; exit 1;;
 esac
 
 CTSOPTS="--stack $CTS_stack --at-boot $CTS_boot $CTS_adv"
 CTSOPTS="$CTSOPTS --facility $CTS_logfacility --logfile $CTS_logfile"
 
 if [ "x$CTS_stonith" != "x" ]; then
 	CTSOPTS="$CTSOPTS --stonith-type $CTS_stonith"
 	[ "x$CTS_stonith_args" != "x" ] &&
 		CTSOPTS="$CTSOPTS --stonith-params \"$CTS_stonith_args\""
 else
 	CTSOPTS="$CTSOPTS --stonith 0"
 fi
 
 CTSOPTS="$CTSOPTS $CTSTESTS"
 
 fibonacci() {
 	F_LIMIT=$1
 	F_N=2
 	F_N_PREV=1
 	while [ $F_N -le $F_LIMIT ]; do
 		echo $F_N
 		F_N_TMP=$F_N
 		F_N=$((F_N+F_N_PREV))
 		F_N_PREV=$F_N_TMP
 	done
 	[ $F_N_PREV -ne $F_LIMIT ] && echo $F_LIMIT
 }
 [ "$SERIES" ] ||
 	SERIES=$(fibonacci "$(echo $CTS_node_list | wc -w)")
 
 get_nodes() {
 	GN_C_NODES=$(echo $CTS_node_list | awk -v n="$1" '
 		{ for( i=1; i<=NF; i++ ) node[cnt++]=$i }
 		END{for( i=0; i<n; i++ ) print node[i] }
 	')
 	if [ "$(echo $GN_C_NODES | wc -w)" != "$1" ]; then
 		msg "not enough nodes in $CTSCTRL"
 		exit 1
 	fi
 	echo $GN_C_NODES
 }
 node_cleanup() {
 	msg "CIB cleanup ($nodes)"
 	for NC_N in $nodes; do
 		ssh $SSHOPTS $NC_N 'rm @CRM_CONFIG_DIR@/*'
 	done
 }
 testnum() {
 	printf '%03d' $1
 }
 mkreports() {
 	msg "Creating reports for the CTS run"
 	MKR_CTS_DIR=$1
 	grep "Running test " $MKR_CTS_DIR/ctsrun.out | tr -d \[\] |
 	awk '{print $6,$NF}' |
 	while read type num; do
 		teststg="`testnum $num`-$type"
 		(
 		cd $MKR_CTS_DIR || return
 		crm_report $CRM_REPORT_OPTS -f "cts:$num" -n "$nodes" "$(pwd)/$teststg" < /dev/null
 		)
 	done
 }
 runcts() {
 	RC_ODIR="$1"
 	msg "Running CTS"
 	python "$CTSDIR/CTSlab.py" $CTSOPTS --nodes "$nodes" > "$RC_ODIR/ctsrun.out" 2>&1 &
 	ctspid=$!
 	tail -f "$RC_ODIR/ctsrun.out" &
 	tailpid=$!
 	wait $ctspid
 	kill $tailpid >/dev/null 2>&1
 }
 
 bench_re='CTS:.*runtime:'
 diginfo() {
 	DI_CTS_DIR="$1"
 	DI_S="$2"
 	filter="$3"
 	(
 	cd "$DI_CTS_DIR" || return
 	for r in [0-9]*.tar.bz2; do
 		tar xjf $r
 		DI_D=$(basename "$r" .tar.bz2)
 		for DI_V in $(grep "$bench_re" "$DI_D/ha-log.txt" | eval "$filter"); do
 			DI_S="$DI_S,$DI_V"
 		done
 		rm -r "$DI_D"
 	done
 	echo $DI_S
 	)
 }
 printheader() {
 	diginfo $1 "" "awk '{print \$(NF-2)}'"
 }
 printstats() {
 	diginfo $1 "$clusize" "awk '{print \$(NF)}'"
 }
 printmedians() {
 	PM_F="$1"
 	PM_S="$clusize"
 	PM_MIDDLE=$((RUNS/2 + 1))
 	set $(head -1 "$PM_F" | sed 's/,/ /g')
 	PM_COLS=$#
 	for PM_I in $(seq 2 $PM_COLS); do
 		PM_V=$(awk -v i=$PM_I -F, '{print $i}' < $PM_F | sort -n | head -$PM_MIDDLE | tail -1)
 		PM_S="$PM_S,$PM_V"
 	done
 	echo $PM_S
 }
 
 rm -f $CSV
 tmpf=`mktemp`
 test -f "$tmpf" || {
 	msg "can't create temporary file"
 	exit 1
 }
 trap "rm -f $tmpf" 0
 for clusize in $SERIES; do
 	nodes=`get_nodes $clusize`
 	outdir=$WORKDIR/$clusize
 	rm -rf $outdir
 	mkdir -p $outdir
 	rm -f $tmpf
 	node_cleanup
 	for i in `seq $RUNS`; do
 		true > $CTS_logfile
 		mkdir -p $outdir/$i
 		runcts $outdir/$i
 		mkreports $outdir/$i
 		printstats $outdir/$i >> $tmpf
 	done
 	[ -f "$CSV" ] || printheader $outdir/1 > $CSV
 	printmedians $tmpf >> $CSV
 	cat $tmpf >> $STATS
 	msg "Statistics for $clusize-node cluster saved"
 done
 msg "Tests done for series $SERIES, output in $CSV and $STATS"