diff --git a/nagios/check_lxc_mem.sh b/nagios/check_lxc_mem.sh
new file mode 100755
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+++ b/nagios/check_lxc_mem.sh
@@ -0,0 +1,369 @@
+#!/bin/sh
+
+# TODO:
+# - high dans une métrique dédiée ? peak aussi ?
+# - -S switch to add swap usage
+# - -W to use memory.high as warning range
+
+# Little check for memory usage of LXC containers
+# GPL v3+ (copyright chl-dev@bugness.org)
+#
+# This was writtent with LXC 5 and cgroup 2 in mind.
+# For older versions, check the excellent
+# https://www.claudiokuenzler.com/monitoring-plugins/check_lxc.php
+
+PROGPATH=$( echo $0 | sed -e 's,[\\/][^\\/][^\\/]*$,,' )
+REVISION="0.1"
+
+# Stop at the first non-catched error
+set -e
+
+# Disable localization to uniformize commands' output
+LANG="C"
+
+# Include check_range()
+# Not needed at the moment
+#. $PROGPATH/utils.sh
+STATE_OK=0
+STATE_WARNING=1
+STATE_CRITICAL=2
+STATE_UNKNOWN=3
+STATE_DEPENDENT=4
+
+# Default values
+RANGE_MEMORY_WARNING="20%"
+RANGE_MEMORY_CRITICAL="10%"
+RANGE_SWAP_WARNING="20%"
+RANGE_SWAP_CRITICAL="10%"
+ADD_MEMORY_PEAK_TO_PERFDATA=0
+MEMORY_TOTAL_SYSTEM="$( free -b | sed -n '/^Mem:/s/^Mem:[[:space:]]*\([[:digit:]]\+\)[[:space:]].*/\1/p' )"
+SWAP_TOTAL_SYSTEM="$( free -b | sed -n '/^Swap:/s/^Swap:[[:space:]]*\([[:digit:]]\+\)[[:space:]].*/\1/p' )"
+USE_MEMORY_HIGH_AS_WARNING=0
+
+# Initial values
+NB_CHECKED_CONTAINERS=0
+
+# Output
+OUTPUT_EXIT_STATUS=$STATE_OK
+OUTPUT_DETAIL_OK=""
+OUTPUT_DETAIL_WARNING=""
+OUTPUT_DETAIL_CRITICAL=""
+OUTPUT_PERFDATA=""
+
+#
+# Help function
+#
+usage() {
+	cat <<EOF
+Usage :
+  $0 [-w warning-free-memory%] [-c critical-free-memory%] [-W] [-P] -n <container|ALL> -n container ...
+
+Example :
+  ./check_lxc_mem.sh -w 20% -c 10% -n monitoring.example.net
+
+  -P : add a perfdata entry for memory.peak
+
+We adopt the same behaviour than check_disks so thresholds are matched
+against "free" space. The example above will trigger a warning if less
+than 20% of memory.max is available.
+
+Thresholds can be specified with a '%' or without, in which case the unit
+is the byte, and with the keyword 'high', instructing to use the memory.high
+value as a threshold.
+
+Note: Since the containers are checked against the latest thresholds specified, order
+      of the arguments is important. Ex:
+      ./check_lxc_mem -w 20% -n container1 -w 50% -n container2
+
+Default values:
+	warning-free-memory:	$RANGE_MEMORY_WARNING
+	critical-free-memory:	$RANGE_MEMORY_CRITICAL
+EOF
+}
+
+check_range_syntax() {
+	return 0
+}
+#	check_range 0 "$1" >/dev/null 2>&1
+#	if [ "$?" -eq "2" ]; then
+#		return 1
+#	fi
+#	return 0
+#}
+
+#
+# Remove the '%' suffix (or error if no '%')
+#
+get_percent() {
+	if [ "$( echo -n "$1" | tail -c 1 )" = "%" ]; then
+		echo -n "$1" | head -c -1
+		return 0
+	fi
+	return 1
+}
+
+#
+# Uniformize thresholds:
+# if "20%" then calculate
+# else leave as is
+# args:
+# 1: MAXVALUE
+# 2: THRESHOLD
+#
+get_absolute_threshold() {
+	local MAXVALUE="$1"
+	local THRESHOLD="$2"
+
+	if get_percent "$THRESHOLD" >/dev/null; then
+		echo "$(( $MAXVALUE * ( 100 - $( get_percent "$THRESHOLD" ) ) / 100 ))"
+	else
+		echo "$(( $MAXVALUE - $THRESHOLD ))"
+	fi
+}
+
+#
+# Returns 1 if value is above threshold, 0 if not
+#
+# args:
+# 1: value
+# 2: maximum
+# 3: threshold (in percent with a '%' suffix, or plain unit)
+#
+check_above_threshold() {
+	local VALUE="$1"
+	local MAXVALUE="$2"
+	local THRESHOLD="$3"
+
+	if [ "$VALUE" -gt "$( get_absolute_threshold "$MAXVALUE" "$THRESHOLD" )" ]; then
+		return 1
+	fi
+	return 0
+}
+
+#
+# The actual check, done in a function to factorize
+# the code between '-n container1' and '-n ALL' calls
+#
+# WARNING: this function modifies global variables.
+#
+# args:
+# 1: container's name
+check_single_container() {
+	CONTAINER="$1"
+
+	# Get the values for the current container
+	MEMORY_CURRENT=$( lxc-cgroup -n "$CONTAINER" memory.current )
+	MEMORY_HIGH=$( lxc-cgroup -n "$CONTAINER" memory.high )
+	MEMORY_MAX=$( lxc-cgroup -n "$CONTAINER" memory.max )
+	SWAP_CURRENT=$( lxc-cgroup -n "$CONTAINER" memory.swap.current )
+	SWAP_HIGH=$( lxc-cgroup -n "$CONTAINER" memory.swap.high )
+	SWAP_MAX=$( lxc-cgroup -n "$CONTAINER" memory.swap.max )
+	# memory.peak is not available everywhere, so don't consult it carelessly.
+	[ "$ADD_MEMORY_PEAK_TO_PERFDATA" = "1" ] && MEMORY_PEAK=$( lxc-cgroup -n $CONTAINER memory.peak )
+
+	# Replace "max" values
+	[ "$MEMORY_MAX" = "max" ] && MEMORY_MAX="$MEMORY_TOTAL_SYSTEM"
+	[ "$MEMORY_HIGH" = "max" ] && MEMORY_HIGH="$MEMORY_TOTAL_SYSTEM"
+	[ "$SWAP_MAX" = "max" ] && SWAP_MAX="$SWAP_TOTAL_SYSTEM"
+	[ "$SWAP_HIGH" = "max" ] && SWAP_HIGH="$SWAP_TOTAL_SYSTEM"
+
+	# If the ranges parameters are set to 'high', we use
+	# memory.high/memory.swap.high as the threshold's value.
+	if [ "$RANGE_MEMORY_WARNING" = "high" ]; then
+		THRESHOLD_MEMORY_WARNING="$MEMORY_HIGH"
+	else
+		THRESHOLD_MEMORY_WARNING="$( get_absolute_threshold "$MEMORY_MAX" "$RANGE_MEMORY_WARNING" )"
+	fi
+	if [ "$RANGE_MEMORY_CRITICAL" = "high" ]; then
+		THRESHOLD_MEMORY_CRITICAL="$MEMORY_HIGH"
+	else
+		THRESHOLD_MEMORY_CRITICAL="$( get_absolute_threshold "$MEMORY_MAX" "$RANGE_MEMORY_CRITICAL" )"
+	fi
+	if [ "$RANGE_SWAP_WARNING" = "high" ]; then
+		THRESHOLD_SWAP_WARNING="$SWAP_HIGH"
+	else
+		THRESHOLD_SWAP_WARNING="$( get_absolute_threshold "$SWAP_MAX" "$RANGE_SWAP_WARNING" )"
+	fi
+	if [ "$RANGE_SWAP_CRITICAL" = "high" ]; then
+		THRESHOLD_SWAP_CRITICAL="$SWAP_HIGH"
+	else
+		THRESHOLD_SWAP_CRITICAL="$( get_absolute_threshold "$SWAP_MAX" "$RANGE_SWAP_CRITICAL" )"
+	fi
+
+	# Fill the perfdata
+	# Remember:
+	# 'label'=value[UOM];[warn];[crit];[min];[max]
+	# label can contain any characters except the equals sign or single quote (')
+	# (except pnp4nagios has trouble with '<>'...)
+	OUTPUT_PERFDATA="$( printf "%s\n'container_%s'=%dB;%d;%d;0;%d" \
+		"$OUTPUT_PERFDATA" \
+		"$( echo $CONTAINER | tr "'=<>" "_" )" \
+		"$MEMORY_CURRENT" \
+		"$THRESHOLD_MEMORY_WARNING" \
+		"$THRESHOLD_MEMORY_CRITICAL" \
+		"$MEMORY_MAX" \
+		)"
+	OUTPUT_PERFDATA="$( printf "%s\n'contswap_%s'=%dB;%d;%d;0;%d" \
+		"$OUTPUT_PERFDATA" \
+		"$( echo $CONTAINER | tr "'=<>" "_" )" \
+		"$SWAP_CURRENT" \
+		"$THRESHOLD_SWAP_WARNING" \
+		"$THRESHOLD_SWAP_CRITICAL" \
+		"$SWAP_MAX" \
+		)"
+
+	# Following the homnymous setting, we add the peak memory consumption to
+	# the perfdata.
+	if [ "$ADD_MEMORY_PEAK_TO_PERFDATA" = "1" ]; then
+		OUTPUT_PERFDATA="$( printf "%s\n'contpeak_%s'=%dB;%d;%d;0;%d" \
+		"$OUTPUT_PERFDATA" \
+		"$( echo $CONTAINER | tr "'=<>" "_" )" \
+		"$MEMORY_PEAK" \
+		"$THRESHOLD_MEMORY_WARNING" \
+		"$THRESHOLD_MEMORY_CRITICAL" \
+		"$MEMORY_MAX" \
+		)"
+	fi
+
+	# Is the value above critical or warning threshold ?
+	if [ "$MEMORY_CURRENT" -gt "$THRESHOLD_MEMORY_CRITICAL" ]; then
+		# Critical state
+		OUTPUT_EXIT_STATUS="$STATE_CRITICAL"
+		OUTPUT_DETAIL_CRITICAL="$OUTPUT_DETAIL_CRITICAL container $CONTAINER uses $( echo $MEMORY_CURRENT | pretty_formatter ) over $( echo $THRESHOLD_MEMORY_CRITICAL | pretty_formatter ) (max: $( echo $MEMORY_MAX | pretty_formatter ))"
+	elif [ "$MEMORY_CURRENT" -gt "$THRESHOLD_MEMORY_WARNING" ]; then
+		# Warning state : let's change the exit status (if not already at a upper level)
+		[ "$OUTPUT_EXIT_STATUS" != "$STATE_CRITICAL" ] && OUTPUT_EXIT_STATUS="$STATE_WARNING"
+		OUTPUT_DETAIL_WARNING="$OUTPUT_DETAIL_WARNING container $CONTAINER uses $( echo $MEMORY_CURRENT | pretty_formatter ) over $( echo $THRESHOLD_MEMORY_WARNING | pretty_formatter ) (max: $( echo $MEMORY_MAX | pretty_formatter ))"
+	fi
+	if [ "$SWAP_CURRENT" -gt "$THRESHOLD_SWAP_CRITICAL" ]; then
+		# Critical state
+		OUTPUT_EXIT_STATUS="$STATE_CRITICAL"
+		OUTPUT_DETAIL_CRITICAL="$OUTPUT_DETAIL_CRITICAL container $CONTAINER uses $( echo $SWAP_CURRENT | pretty_formatter ) over $( echo $THRESHOLD_SWAP_CRITICAL | pretty_formatter ) (max: $( echo $SWAP_MAX | pretty_formatter ))"
+	elif [ "$SWAP_CURRENT" -gt "$THRESHOLD_SWAP_WARNING" ]; then
+		# Warning state : let's change the exit status (if not already at a upper level)
+		[ "$OUTPUT_EXIT_STATUS" != "$STATE_CRITICAL" ] && OUTPUT_EXIT_STATUS="$STATE_WARNING"
+		OUTPUT_DETAIL_WARNING="$OUTPUT_DETAIL_WARNING container $CONTAINER uses $( echo $SWAP_CURRENT | pretty_formatter ) over $( echo $THRESHOLD_SWAP_WARNING | pretty_formatter ) (max: $( echo $SWAP_MAX | pretty_formatter ))"
+	fi
+
+	# Little counter, 'cause we never know, it might be useful :)
+	NB_CHECKED_CONTAINERS=$(( $NB_CHECKED_CONTAINERS + 1 ))
+}
+
+#
+# Try to get a pretty formatter and
+# fall back to "cat"
+#
+# Usage: echo "1024" | pretty_formatter
+#
+pretty_formatter() {
+	if command -v numfmt >/dev/null 2>&1; then
+		numfmt --to si
+	else
+		cat -
+	fi
+}
+
+# Some early checks
+# - The following base commands are required
+for cmd in head tail sed lxc-ls lxc-cgroup free sort tr; do
+	if ! command -v $cmd 1>/dev/null
+		then echo "UNKNOWN: $cmd not found, please check if command exists and PATH is correct"
+		exit $STATE_UNKNOWN
+	fi
+done
+# - Check if memory accounting is enableda
+if ! grep -E '^memory[[:space:]].*[[:space:]]1$' /proc/cgroups >/dev/null 2>&1; then
+	echo "cgroup is not defined as kernel cmdline parameter (cgroup_enable=memory)"
+	exit $STATE_UNKNOWN
+fi
+
+#
+# Loop on parameters + tests
+#
+while getopts hw:c:W:C:n:P f; do
+	case "$f" in
+		'h')
+			usage
+			exit
+			;;
+
+		'w')
+			if check_range_syntax "$OPTARG" >/dev/null; then
+				RANGE_MEMORY_WARNING="$OPTARG"
+			else
+				echo "UNKNOWN: invalid range."
+				exit 3
+			fi
+			;;
+
+		'c')
+			if check_range_syntax "$OPTARG" >/dev/null; then
+				RANGE_MEMORY_CRITICAL="$OPTARG"
+			else
+				echo "UNKNOWN: invalid range."
+				exit 3
+			fi
+			;;
+
+		'W')
+			if check_range_syntax "$OPTARG" >/dev/null; then
+				RANGE_SWAP_WARNING="$OPTARG"
+			else
+				echo "UNKNOWN: invalid range."
+				exit 3
+			fi
+			;;
+
+		'C')
+			if check_range_syntax "$OPTARG" >/dev/null; then
+				RANGE_SWAP_CRITICAL="$OPTARG"
+			else
+				echo "UNKNOWN: invalid range."
+				exit 3
+			fi
+			;;
+
+		'n')
+			# Immediatly launch the check on this/those container(s)
+			if [ "$OPTARG" = "ALL" ]; then
+				for CONTAINER in $( lxc-ls --running ); do
+					check_single_container "$CONTAINER"
+				done
+			else
+				check_single_container "$OPTARG"
+			fi
+			;;
+
+		'P')
+			# Toggle the insertion of memory.peak as a perfdata entry
+			ADD_MEMORY_PEAK_TO_PERFDATA=$(( ( $ADD_MEMORY_PEAK_TO_PERFDATA + 1 ) % 2 ))
+			;;
+
+		\?)
+			usage
+			exit 1
+			;;
+	esac
+done
+
+case "$OUTPUT_EXIT_STATUS" in
+	'0')
+		printf "OK %s" "$OUTPUT_DETAIL_OK"
+		;;
+	'1')
+		printf "WARNING %s" "$OUTPUT_DETAIL_WARNING"
+		;;
+	'2')
+		printf "CRITICAL %s" "$OUTPUT_DETAIL_CRITICAL"
+		;;
+	*)
+		printf "UNKNOWN"
+		;;
+esac
+
+# Add the containers' counter to the perfdata
+OUTPUT_PERFDATA="$( printf "%s\n%s" "$OUTPUT_PERFDATA" "nb_containers=$NB_CHECKED_CONTAINERS" )"
+
+# We sort the perfdata because of a weird bug in some icinga/pnp4nagios interactions
+printf "|%s\n" "$( printf "%s" "$OUTPUT_PERFDATA" | sort | grep -v "^$" | tr "\n" " " )"
+exit $OUTPUT_EXIT_STATUS