diff --git a/nagios/check_gitlab_readiness.sh b/nagios/check_gitlab_readiness.sh
new file mode 100755
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+++ b/nagios/check_gitlab_readiness.sh
@@ -0,0 +1,203 @@
+#!/bin/bash
+
+# Little monitoring script to check the readiness of a Gitlab instance.
+#
+# Remember that you have to whitelist the IP of your monitoring system :
+# gitlab.rb:
+#  gitlab_rails['monitoring_whitelist'] = ['127.0.0.0/8', '::1/128', ...]
+# See https://docs.gitlab.com/ee/administration/monitoring/health_check.html
+#
+# Licence: WTFPL
+# Copyright: chl-dev@bugness.org 2024
+
+PROGPATH=$( echo $0 | sed -e 's,[\\/][^\\/][^\\/]*$,,' )
+REVISION="0.1"
+
+# Default values
+GITLAB_HOSTNAME="localhost"
+GITLAB_URL=""
+GITLAB_URL_PROTOCOL="https"
+NB_CHECKS_RANGE="15:20"
+
+# Include check_range() and STATE_OK, STATE_WARNING, ... variables
+. $PROGPATH/utils.sh
+
+# Output
+OUTPUT_CPT_CHECKS=0
+OUTPUT_EXIT_STATUS=0
+OUTPUT_DETAIL_OK=""
+OUTPUT_DETAIL_WARNING=""
+OUTPUT_DETAIL_CRITICAL=""
+OUTPUT_DETAIL_UNKNOWN=""
+OUTPUT_PERFDATA=""
+
+
+# Stop at first uncaught error
+set -eu
+
+# Wrapper to use whatever is available to make HTTP queries
+fetch_with_curl_wget_or_whatever () {
+	if which "wget" >/dev/null 2>&1; then
+		wget -q -O - "$1"
+	elif which "curl" >/dev/null 2>&1 ; then
+		curl -s "$1"
+	else
+		echo "UNKNOWN: no wget/curl/whatever available to make HTTP queries."
+		exit $STATE_UNKNOWN
+	fi
+}
+
+check_http_status_200() {
+	if which "wget" >/dev/null 2>&1; then
+		wget -q --spider "$1"
+	elif which "curl" >/dev/null 2>&1 ; then
+		test "$( curl -s -o /dev/null -I -w "%{http_code}" "$1" )" == "200"
+	else
+		echo "UNKNOWN: no wget/curl/whatever available to make HTTP queries."
+		exit $STATE_UNKNOWN
+	fi
+}
+
+print_full_url() {
+	if [ -n "$GITLAB_URL" ]; then
+		echo "$GITLAB_URL"
+	else
+		echo "$GITLAB_URL_PROTOCOL://$GITLAB_HOSTNAME/-/readiness?all=1"
+	fi
+}
+
+# Help function
+usage() {
+	cat <<EOF
+Usage :
+  $0 [-H hostname] [-U full_URL] [-sS] [ -c nb_checks_range ]
+
+	-c Expected number of checks
+	-s Use HTTP to query the hostname
+	-S Use HTTPS to query the hostname (default)
+
+Examples:
+	./check_gitlab.sh -H forge.example.net
+	./check_gitlab.sh -U https://forge.example.net/ -c 20:42
+
+Default values:
+	full_URL: $( print_full_url )
+	nb_checks_range: $NB_CHECKS_RANGE
+EOF
+}
+
+# Loop on parameters
+while getopts c:hH:sSU: f; do
+	case "$f" in
+		'c')
+			NB_CHECKS_RANGE="$OPTARG"
+			;;
+
+		'h')
+			usage
+			exit
+			;;
+
+		'H')
+			GITLAB_HOSTNAME="$OPTARG"
+			GITLAB_URL=""  # To generate the URL from the hostname, see print_full_url()
+			;;
+
+		's')
+			GITLAB_URL_PROTOCOL="http"
+			;;
+
+		'S')
+			GITLAB_URL_PROTOCOL="https"
+			;;
+
+		'U')
+			GITLAB_URL="$OPTARG"
+			;;
+
+		?)
+			usage
+			exit 1
+			;;
+	esac
+done
+
+if ! which jq >/dev/null; then
+	echo "UNKNOWN command 'jq' not available."
+	exit $STATE_UNKNOWN
+fi
+
+# First, let's check that the URL responds with 200/OK
+#if ! check_http_status_200 "$( print_full_url )"; then
+#	echo TODO later. Since it needs 2 queries, it could lead to inconsistencies if we get a 200 now and an error later.
+#           Would the best way be to set another probe ?
+#           check_https!-H $HOSTNAME$ -f warning -u /-/readiness?all=1
+#           check_https!-H $HOSTNAME$ -f warning -u /-/health -s "GitLab OK"
+#fi
+
+if ! JSONDATA="$( fetch_with_curl_wget_or_whatever "$( print_full_url )" )"; then
+	echo "UNKNOWN error fetching the URL '$( print_full_url )'"
+	exit $STATE_UNKNOWN
+fi
+
+while read KEY; do
+	OUTPUT_CPT_CHECKS=$(( $OUTPUT_CPT_CHECKS + 1 ))
+	if [ "$KEY" == "status" ]; then
+		STATUS="$( printf "%s\n" "$JSONDATA" | jq ".$KEY" )"
+	else
+		STATUS="$( printf "%s\n" "$JSONDATA" | jq ".$KEY[0].status" )"
+	fi
+	if [ "$STATUS" != '"ok"' ]; then
+		OUTPUT_DETAIL_CRITICAL="$( printf "%s Status for key '$KEY': %s" "$OUTPUT_DETAIL_CRITICAL" "$STATUS" )"
+		OUTPUT_EXIT_STATUS=$STATE_CRITICAL
+	fi
+done <<EOF
+$( printf "%s\n" "$JSONDATA" | jq 'keys[]' | sed 's/\(^"\|"$\)//g' )
+EOF
+
+# Let's check that the number of checks checks out
+set +e
+check_range "$OUTPUT_CPT_CHECKS" "$NB_CHECKS_RANGE"
+STATUS="$?"
+set -e
+if [ "$STATUS" -eq 0 ]; then
+	if [ "$OUTPUT_EXIT_STATUS" == "$STATE_OK" ]; then
+		OUTPUT_EXIT_STATUS=$STATE_WARNING
+		OUTPUT_DETAIL_WARNING="$OUTPUT_DETAIL_WARNING Nb checks outside of range: $OUTPUT_CPT_CHECKS / $NB_CHECKS_RANGE"
+	fi
+elif [ "$STATUS" -eq 2 ]; then
+	if [ "$OUTPUT_EXIT_STATUS" != "$STATE_CRITICAL" ]; then
+		OUTPUT_EXIT_STATUS=$STATE_UNKNOWN
+		OUTPUT_DETAIL_UNKNOWN="$OUTPUT_DETAIL_UNKNOWN check_range() on error: $OUTPUT_CPT_CHECKS / $NB_CHECKS_RANGE"
+	fi
+fi
+
+# final output
+case "$OUTPUT_EXIT_STATUS" in
+	"$STATE_OK")
+		printf "OK $OUTPUT_DETAIL_OK"
+		;;
+
+	"$STATE_WARNING")
+		printf "WARNING $OUTPUT_DETAIL_WARNING"
+		;;
+
+	"$STATE_CRITICAL")
+		printf "CRITICAL $OUTPUT_DETAIL_CRITICAL"
+		;;
+
+	"$STATE_UNKNOWN")
+		printf "UNKNOWN $OUTPUT_DETAIL_UNKNOWN"
+		;;
+
+	*)
+		printf "WTF"
+		;;
+esac
+
+# Add the checks counter to the perfdata
+OUTPUT_PERFDATA="$( printf "%s\n%s" "$OUTPUT_PERFDATA" "nb_checks=$OUTPUT_CPT_CHECKS;$NB_CHECKS_RANGE;;0" )"
+
+# We sort the perfdata because of a weird bug in some icinga/pnp4nagios interactions
+printf "|%s\n" "$( printf "%s" "$OUTPUT_PERFDATA" | sort | grep -v "^$" | tr "\n" " " )"
+exit "$OUTPUT_EXIT_STATUS"