Nagios plugin for Synology NAS

Last updated: Sep 8, 2020

Here is a Bourne shell Nagios plugin which can be executed directly from the NAS Synology. It's inspired by the great work of Jur Groen and Nicolas Ordonez.

The plugin will check the following elements :

System status (Power, Fans)
Disks status
RAID status
DSM update status
Disk usage

Configuration

DSM : 5, 6

Instructions

Enable SNMPv3

First we need to enable SNMPv3 from the Web Admin (set the same password for SHA and AES protocols) :

The plugin can be used remotly (from the Synology NAS) or localy (from the Nagios server).
⚠️ Note that the disk usage functionality is only available with the remote method.

From Nagios Server, install sudo and snmp tools :

root@host:~# apt install sudo snmp

Local method

Here, the plugin will be executed from the Nagios Server and will send requests via SNMPv3.

Add execution rights to the plugin

root@host:~# chmod +x ./check_syno.sh

Execute as Nagios user to be sure that everyhting is fine

root@host:~# sudo -u nagios ./check_syno.sh -u user -p PassW0RD -h 192.168.1.200

Output

OK - The NAS DS218j - SN : 254262N214800 - DSM : DSM 6.2-25426 is fine
NAS temperature is 40°C - Fan Status : OK - CPU Fan Status : OK - Power Status : OK - System Status : OK 
The Hard Drive 2 model HD204UI is functioning normally
The Hard Drive 1 model WD20EARX-00PASB0 is functioning normally
The RAID Storage Pool 1 is fine The RAID Volume 2 is fine

Remote method

Here, the plugin will be launched from the Nagios Server via ssh and executed on the NAS Synology. In this mode disk usage functionality will be available.

Create new user from Web Interface

root user is not allowed to connect through ssh so we need to create a new user with administrators rights :

Synology NAS Web Interface User Creation Wizard

Enable ssh key authentication

Still from NAS Synology, edit /etc/ssh/sshd_config and uncomment this lines :

SAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys

Restart sshd service :

synoservicectl --restart sshd

Set correct files permissions :

chmod 0711 ~
chmod 0711 ~/.ssh
chmod 0600 ~/.ssh/authorized_keys

Now, from Nagios Server generate rsa keys for nagios User :

root@host:~# sudo -u nagios ssh-keygen -t rsa

From Nagios Server, export nagios user SSH key to the Synology NAS :

root@host:~# sudo -u nagios cat /var/lib/nagios/.ssh/id_rsa.pub | ssh SSH_USER@192.168.1.200 'cat >> .ssh/authorized_keys'

Copy the plugin to the NAS :

user@host:~$ scp check_syno.sh SSH_USER@192.168.1.200:/usr/syno/sbin/

and run the following command :

root@host:~# sudo -u nagios ssh -l SSH_USER 192.168.1.200 /usr/syno/sbin/check_syno.sh -h 127.0.0.1 -u SNMP_USER -p SNMP_PASSWORD -w 80 -c 90

Output

OK - The NAS DS218j - SN : 254262N214800 - DSM : DSM 6.2-25426 is fine
NAS temperature is 40°C - Fan Status : OK - CPU Fan Status : OK - Power Status : OK - System Status : OK 
The Hard Drive 2 model HD204UI is functioning normally
The Hard Drive 1 model WD20EARX-00PASB0 is functioning normally
The RAID Storage Pool 1 is fine The RAID Volume 2 is fine 
/volume2 is used at 49%, 947G remaining free space 
/tmp is used at 1%, 249M remaining free space 
/ is used at 42%, 1.3G remaining free space

You can read silica.io article for detailled informations about key authentification on a Synology NAS.

check_syno.sh

#! /bin/bash
# check_snmp_synology for nagios version 1.4
# 30.04.2013  Nicolas Ordonez, Switzerland
# 03.10.2014  Jur Groen, Syso IT Services, The Netherlands
# 06.11.2014  shebangthedolphins.net
# 05.12.2014  shebangthedolphins.net add disk usage check
# 17.09.2020  shebangthedolphins.net bugs correction, DSM 6 compatibility, improve snmpv3 security (SHA and AES)
#---------------------------------------------------
# this plugin checks the health of your Synology NAS
# - System status (Power, Fans)
# - Disks status
# - RAID status
# - DSM update status
#
# this plugin now makes use of SNMP V3 for enhanced security
# Tested with DSM 6.0
#---------------------------------------------------
# Based on http://download.synology.com/download/ds/userguide/Synology_DiskStation_MIB_Guide_enu_20110725.pdf
#---------------------------------------------------

#Variables definition
## NAGIOS returns
CRITICAL=2
WARNING=1
OK=0
RETURN=0                #everything's fine, by default

## If arguments found
option_found=0

#get the number of partitions
NB_part=$(df -h | grep "/" | grep -v "\(\/tmpfs\|\/shm\|\/sys\|\/run\|\/dev$\|\/rootfs\)" | wc -l)

##OIDs
OID_syno="1.3.6.1.4.1.6574"
OID_model="1.3.6.1.4.1.6574.1.5.1.0"
OID_serialNumber="1.3.6.1.4.1.6574.1.5.2.0"
OID_DSMVersion="1.3.6.1.4.1.6574.1.5.3.0"
OID_upgradeAvailable="1.3.6.1.4.1.6574.1.5.4.0"
OID_systemStatus="1.3.6.1.4.1.6574.1.1.0"
OID_powerStatus="1.3.6.1.4.1.6574.1.3.0"
OID_systemFanStatus="1.3.6.1.4.1.6574.1.4.1.0"
OID_CPUFanStatus="1.3.6.1.4.1.6574.1.4.2.0"
OID_temp="1.3.6.1.4.1.6574.1.2.0"

OID_disk=""
OID_diskID="1.3.6.1.4.1.6574.2.1.1.2"
OID_diskModel="1.3.6.1.4.1.6574.2.1.1.3"
OID_diskStatus="1.3.6.1.4.1.6574.2.1.1.5"
OID_diskTemp="1.3.6.1.4.1.6574.2.1.1.6"

OID_RAID=""
OID_RAIDName="1.3.6.1.4.1.6574.3.1.1.2"
OID_RAIDStatus="1.3.6.1.4.1.6574.3.1.1.3"

#Functions
FunctionDiskSpace()
{
	if [ "$HOSTNAME" == "127.0.0.1" ]; then #check disk usage only if executed on the synology nas
	    for i in $(seq 1 "$NB_part"); do
		PARTITION=$(df -h | grep "/" | tr -s " " | grep -v "\(\/tmpfs\|\/shm\|\/sys\|\/run\|\/dev$\|\/rootfs\)" | head -n "$i" | tail -n 1 | grep "/" | cut -d " " -f 6)
		UTI=$(df -h | grep "/" | tr -s " " | grep -v "\(\/tmpfs\|\/shm\|\/sys\|\/run\|\/dev$\|\/rootfs\)" | head -n "$i" | tail -n 1 | grep "/" | cut -d " " -f 5)
		DISPO=$(df -h | grep "/" | tr -s " " | grep -v "\(\/tmpfs\|\/shm\|\/sys\|\/run\|\/dev$\|\/rootfs\)" | head -n "$i" | tail -n 1 | grep "/" | cut -d " " -f 4)
		SORTIE="$(echo ""$PARTITION" is used at "$UTI", "$DISPO" remaining free space") \n"$SORTIE""
		TEST=$(echo "$UTI" | sed 's/%//')
		if [ $TEST -gt "$WARNING_SPACE" ]; then
		    RETURN="$WARNING"
		    if [ "$TEST" -gt "$CRITICAL_SPACE" ]; then
			RETURN="$CRITICAL"
		    fi
		fi
	    done
	    if [ "$1" == "Output" ]; then
		echo -e "$SORTIE"
	    fi
	    SORTIE=""
	fi
}

usage()
{
        echo "usage: ./check_snmp_synology -u [snmp username] -p [snmp password] -h [hostname] -w [warning occuped space in %] -c [max occuped space in %]"
        echo ""
        exit 3
}

while getopts u:p:h:c:w: OPTNAME; do
        case "$OPTNAME" in
        u)
                SNMPUSERNAME="$OPTARG"
                option_found=1
                ;;
        p)
                SNMPPASSWORD="$OPTARG"
                option_found=1
                ;;

        h)
                HOSTNAME="$OPTARG"
                option_found=1
                ;;
        w)
                WARNING_SPACE="$OPTARG"
                option_found=1
                ;;
        c)
                CRITICAL_SPACE="$OPTARG"
                option_found=1
                ;;
        *)
                usage
                ;;
        esac
done

# Script beginning :
if [ "$option_found" -eq "0" ] || [ "$HOSTNAME" == "" ] ; then
        usage
else
        # DiskSpace function usage but without print anything
        FunctionDiskSpace NoOutput

	nbDISK=$(snmpwalk -OQne -v 3 -t 10 -l authNoPriv -u $SNMPUSERNAME -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" $HOSTNAME .1.3.6.1.4.1.6574.2.1.1.3 2>/dev/null|wc -l)
        #if SNMP failed, exit with error
        if [ "$?" != "0" ] ; then
                echo "CRITICAL - Problem with SNMP request"
                exit "$CRITICAL"
        fi

	nbRAID=$(snmpwalk -OQne -v 3 -t 10 -l authNoPriv -u $SNMPUSERNAME -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" $HOSTNAME .1.3.6.1.4.1.6574.3.1.1.2 2>/dev/null|wc -l)

        for i in $(seq 1 $nbDISK);
        do
                OID_DISK="$OID_disk $OID_diskID.$(($i-1)) $OID_diskModel.$(($i-1)) $OID_diskStatus.$(($i-1)) $OID_diskTemp.$(($i-1)) "
        done
        for i in $(seq 1 $nbRAID);
        do
                OID_RAID="$OID_RAID $OID_RAIDName.$(($i-1)) $OID_RAIDStatus.$(($i-1))"
        done

        #MODEL
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_model" 2>/dev/null)
        model=$(echo $temp | grep $OID_model | cut -d " " -f3 | sed "s/\"//g")
        #echo $model

        #serialNumber
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_serialNumber" 2>/dev/null)
        serialNumber=$(echo $temp | grep $OID_serialNumber | cut -d " " -f3 | sed "s/\"//g")
        #echo $serialNumber

        #OID_upgradeAvailable
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_upgradeAvailable" 2>/dev/null)

        #OID_DSMVersion
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_DSMVersion" 2>/dev/null)
        DSMVersion=$(echo $temp | grep $OID_DSMVersion | cut -d "\"" -f2)
        #echo "$DSMVersion"

        #OID_systemStatus
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_systemStatus" 2>/dev/null)
        systemStatus=$(echo $temp | grep $OID_systemStatus | cut -d " " -f3 | sed "s/\"//g")
        #echo $systemStatus

        #OID_powerStatus
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_powerStatus" 2>/dev/null)
        powerStatus=$(echo $temp | grep $OID_powerStatus | cut -d " " -f3 | sed "s/\"//g")
        #echo $powerStatus

        #OID_systemFanStatus
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_systemFanStatus" 2>/dev/null)
        systemFanStatus=$(echo $temp | grep $OID_systemFanStatus | cut -d " " -f3 | sed "s/\"//g")
        #echo $systemFanStatus

        #OID_CPUFanStatus
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_CPUFanStatus" 2>/dev/null)
        CPUFanStatus=$(echo $temp | grep $OID_CPUFanStatus | cut -d " " -f3 | sed "s/\"//g")
        #echo $CPUFanStatus

        #OID_temp
        temp=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_temp" 2>/dev/null)
        TEMP=$(echo "$temp" | grep "$OID_temp" | cut -d " " -f3 | sed "s/\"//g")
        #echo "$TEMP"

        #Disks state
        for i in $(seq 1 "$nbDISK")
        do
                temp01=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_diskStatus.$(($i-1))" 2>/dev/null)
                temp02=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_diskModel.$(($i-1))" 2>/dev/null)
                temp03=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_diskID.$(($i-1))" 2>/dev/null)
                temp04=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_diskTemp.$(($i-1))" 2>/dev/null)

                status=$(echo "$temp01" | grep "$OID_disk" | cut -d " " -f3)
                diskmodel=$(echo "$temp02" | grep "$OID_disk" | cut -d "\"" -f2 | sed 's/\s//g')
                ID=$(echo "$temp03" | grep "$OID_disk" | cut -d "\"" -f2)
                temp=$(echo "$temp04" | grep "$OID_disk" | cut -d " " -f3)
                if [ "$status" -eq "5" ]; then
                        disques="$(echo "The Hard "$ID" model "$diskmodel" is damaged")\\n"$disques""
                        RETURN="$CRITICAL"
                elif [ "$status" -eq "4" ]; then
                        disques="$(echo "The Hard "$ID" model "$diskmodel" has partitions damaged")\\n"$disques""
                        RETURN="$CRITICAL"
                elif [ "$status" -eq "3" ]; then
                        disques="$(echo "The Hard "$ID" model "$diskmodel" is not partitioned")\\n"$disques""
                        RETURN="$WARNING"
                elif [ "$status" -eq "2" ]; then
                        disques="$(echo "The Hard "$ID" model "$diskmodel" has system partitions but no data")\\n"$disques""
                        RETURN="$WARNING"
                elif [ "$status" -eq "1" ]; then
                        disques="$(echo "The Hard "$ID" model "$diskmodel" is functioning normally")\\n"$disques""
                        #RETURN=$(echo "$OK")
                else
                        disques="$(echo "The Hard "$ID" model "$diskmodel" is in an unknown state")\\n"$disques""
                        RETURN="$WARNING"
                fi
        done

        #RAID State
        for i in $(seq 1 "$nbRAID")
        do
                temp01=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_RAIDName.$(($i-1))" 2>/dev/null)
                temp02=$(snmpwalk -OQne -t 10 -v 3 -l authNoPriv -u "$SNMPUSERNAME" -a SHA -A "$SNMPPASSWORD" -x AES -X "$SNMPPASSWORD" "$HOSTNAME" "$OID_RAIDStatus.$(($i-1))" 2>/dev/null)
                Volume=$(echo "$temp01" | grep "$OID_disk" | cut -d "\"" -f2)
                Statut=$(echo "$temp02" | grep "$OID_disk" | cut -d " " -f3)
                if [ "$Statut" -eq "11" ]; then
                        raids="$(echo "The RAID "$Volume" is degraded") "$raids""
                        RETURN="$CRITICAL"
                elif [ "$Statut" -eq "12" ]; then
                        raids="$(echo "The RAID "$Volume" has crashed") "$raids""
                        RETURN="$CRITICAL"
                elif [ "$Statut" -eq "1" ]; then
                        raids="$(echo "The RAID "$Volume" is fine") "$raids""
                else
                        raids="$(echo "The RAID "$Volume" is in an unknown state") "$raids""
                        RETURN="$WARNING"
                fi
        done

        # Nagios States
        if [ "$RETURN" -eq "2" ] || [ "$systemFanStatus" -eq "2" ] || [ "$CPUFanStatus" -eq "2" ] || [ "$powerStatus" -eq "2" ] || [ "$systemStatus" -eq "2" ]; then
                echo -e "CRITICAL - The NAS "$model" - SN : "$serialNumber" - DSM : "$DSMVersion" has a problem"
                echo -e "NAS temperature is "$TEMP"°C - Fan Status : "$systemFanStatus" - CPU Fan Status : "$CPUFanStatus" - Power Status : "$powerStatus" - System Status : "$systemStatus" " | sed 's/ 1 / OK
                for i in "$disques"; do
                        echo -e "$i" | sed '/^$/d'
                done
                for i in "$raids"; do
                        echo -e "$i" | sed '/^$/d'
                done
                FunctionDiskSpace Output

                exit "$CRITICAL"
        fi
        if [ "$RETURN" -eq "1" ]; then
                echo -e "WARNING - The NAS "$model" - SN : "$serialNumber" - DSM : "$DSMVersion" is in Warning state"
                echo -e "NAS temperature is "$TEMP"°C - Fan Status : "$systemFanStatus" - CPU Fan Status : "$CPUFanStatus" - Power Status : "$powerStatus" - System Status : "$systemStatus" " | sed 's/ 1 / OK
                for i in "$disques"; do
                        echo -e "$i" | sed '/^$/d'
                done
                for i in "$raids"; do
                        echo -e "$i" | sed '/^$/d'
                done
                FunctionDiskSpace Output

                exit "$WARNING"
        fi
        if [ "$RETURN" -eq "0" ]; then
		echo -e "OK - The NAS "$model" - SN : "$serialNumber" - DSM : "$DSMVersion" is fine"
		echo -e "NAS temperature is "$TEMP"°C - Fan Status : "$systemFanStatus" - CPU Fan Status : "$CPUFanStatus" - Power Status : "$powerStatus" - System Status : "$systemStatus" " | sed 's/ 1 / OK /g' | sed 's/ 2 / FAILED /g'
		for i in "$disques"; do
			echo -e "$i" | sed '/^$/d'
		done
		for i in "$raids"; do
			echo -e "$i" | sed '/^$/d'
		done
		FunctionDiskSpace Output
		
		exit "$OK"
	fi 
	echo -e "CRITICAL - The NAS "$model" - SN : "$serialNumber" - DSM : "$DSMVersion" is in an indeterminate State"
	exit "$CRITICAL"
fi

Nagios config

I don't use Nagios anymore but the configuration should be like this.

command.cfg

define command {
    command_name   check_syno_local
    command_line    /usr/local/sbin/check_syno.sh -u $ARG1$ -p $ARG2$ -h $ARG3$
}
define command {
    command_name   check_syno_remote
    command_line    ssh -l $ARG1$ $ARG2$ /usr/syno/sbin/check_syno.sh -h 127.0.0.1 -u $ARG3$ -p $ARG4$ -w 80 -c 90
}

service.cfg

define service{
    use                     nassynology-service
    host_name               NAS Synology
    servicegroups           nas-synology
    service_description     Backup Local NAS
    check_command           check_syno_local!SNMP_USER PassW0RD 192.168.1.200
}
define service{
    use                     nassynology-service
    host_name               NAS Synology
    servicegroups           nas-synology
    service_description     Backup Remote NAS
    check_command           check_syno_remote!SSH_USER 192.168.1.200 SNMP_USER PassW0RD
}

Output

Download : check_syno.sh
Nagios Exchange : https://exchange.nagios.org/