Nagios is collecting stats from my RHEL server. I do not see that the nrpe agent nor snmp is running. How is this working?

Currently, I'm using nrpe to monitor clients using Nagios but when nrpe goes down then all the stat goes to an unknown state which causes it difficult to monitor critical alerts... What and how should I prove so that I never miss critical alerts?

Nagios itself has the way to check its config file for validity, to ensure it would at least load the config without errors:

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Is it possible to do the same thing for the NRPE daemon? The manual page for NRPE suggests it doesn't support that. I intend to update the NRPE config with Ansible's lineinfile module, so I want to check for validity to be sure at least I don't break the monitoring completely.

Steps done: **On Nagios Server (CentOS 7)** yum install nagios nagios-plugins-all **On Target (CentOS 7)** yum install nrpe nagios-plugins-all modified nrpe.cfg and added master IP to allowed_hosts systemctl enable nrpe && systemctl start nrpe Now I'm trying to add a service check with check_nrpe so I defined host, contact, contactgroup then check_nrpe command nano /etc/nagios/objects/commands.cfg define command{ command_name check_nrpe command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$ } then added services for the nrpe check nano /etc/nagios/objects/services.cfg define service { use basic-new-service name check-load-service normal_check_interval 3 retry_check_interval 1 notification_interval 30 notification_options w,c,r,u check_command check_nrpe!check_load register 0 } define service { use check-load-service service_description SYS_HostLoad contact_groups Audit host_name TGT } nagios service started successfully systemctl enable nagios && systemctl start nagios I can verify check_nrpe returns Ok status directly from CLI # /usr/lib64/nagios/plugins/check_nrpe -H TGT -c check_load OK - load average per CPU: 0.00, 0.00, 0.01|load1=0.000;0.150;0.300;0; load5=0.002;0.100;0.250;0; load15=0.008;0.050;0.200;0; but in dashboard check_nrpe check is unable to succeed, due to permissions. (which I had already set as nagios:nagios for both /etc/nagios and /usr/lib64/nagios/plugins) it's showing this error on dashboard against this check (Return code of 13 for service 'SYS_HostLoad' on host 'TGT' was out of bounds)

> Note: I am referring to an old Ubuntu 14.04 ! :( Don't blame me, it's not my fault. I have this process When I kill, something restart it automatically. I need to stop it! I tried what follows without succcess # systemctl disable nrpe.service # systemctl stop nrpe.service # systemctl status nrpe.service nrpe.service - Nagios Remote Plugin Executor Loaded: loaded (/etc/systemd/system/nrpe.service; disabled) Active: failed (Result: exit-code) since Tue 2021-08-17 09:44:23 CEST; 14min ago Docs: http://www.nagios.org/documentation Main PID: 21974 (code=exited, status=1/FAILURE) CGroup: name=dsystemd:/system/nrpe.service Aug 17 09:44:23 localhost nrpe: Starting up daemon Aug 17 09:44:23 localhost nrpe: Bind to port 5666 on 0.0.0.0 failed: Address already in use. I tried also # /etc/init.d/nagios-nrpe-server stop # /etc/init.d/nagios-nrpe-server status # But in htop the process is still running I queried status of service using old way # service --status-all [ - ] nagios-nrpe-server # service nagios-nrpe-server stop But the process is still here (with a different PID, so it's auto restarted) Also # systemctl stop nagios-nrpe-server Failed to issue method call: Unit nagios-nrpe-server.service not loaded. # systemctl disable nagios-nrpe-server Failed to issue method call: No such file or directory

I am trying to install NRPE (nagios remote plugin executor) in a CentOS system. In the configuration step, the document I have been given to refer to says, ./configure --enable-command-args --with-nagios-user=nagios --with-nagios-group=nagios --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib/x86_64-linux-gnu But the directory /usr/lib/x86_64-linux-gnu is not present in my system. These are the contents of the /usr/lib directory: [root@pr2 ~]# ls /usr/lib lib/ lib64/ libexec/ [root@pr2 ~]# ls /usr/lib/ binfmt.d/ grub/ NetworkManager/ sysctl.d/ cpp kbd/ polkit-1/ systemd/ debug/ kdump/ python2.7/ tmpfiles.d/ dracut/ kernel/ rpm/ tuned/ firewalld/ locale/ sendmail udev/ firmware/ modprobe.d/ sendmail.postfix yum-plugins/ games/ modules/ sendmail.sendmail gcc/ modules-load.d/ sse2/ According to the answer here , it may be that more modern system have this directory (although the question and answer in the link is about Ubuntu, I think it is safe to assume that the same is true of CentOS systems, since my installation doc for CentOS mentions this directory?). So, **what do I replace the location in the aforementioned command with if I am missing that directory**? In case it helps, this is the version of CentOS in my machine: [root@pr2 ~]# rpm --query centos-release centos-release-7-4.1708.el7.centos.x86_64

I am getting SSL Handshake errors with NRPE after enabling SSL. It worked perfectly fine without SSL doing check_nrpe. The allowed host is correct and when run without SSL enabled it shows the proper version. Both are running 4.3 on CentOS Linux release 7.9.2009 (Core) I did not compile NRPE or nagios from source I installed via Yum. Here are the configs I feel are important to this issue. here is the error I'm getting logged... It says wrong version but both are running same version of NRPE. I am using a real purchased wildcard cert... Same cert on both sides. Cert matches the domain name of the server. nrpe --version NRPE - Nagios Remote Plugin Executor Version: 4.0.3 Same version on both for openssl openssl version OpenSSL 1.0.2k-fips 26 Jan 2017 When I run ./check_nrpe -H hostname.domain.com I get CHECK_NRPE: (ssl_err != 5) Error - Could not complete SSL handshake with 10.1.1.125: 1 On the other server it logs: Jan 5 12:48:54 nagiostest2 nrpe: Error: (ERR_get_error_line_data = 336130315), Could not complete SSL handshake with 10.1.1.64: wrong version number Jan 5 12:51:11 nagiostest2 nrpe: CONN_CHECK_PEER: checking if host is allowed: 10.1.1.64 port 16075 Jan 5 12:51:11 nagiostest2 nrpe: is_an_allowed_host (AF_INET): is host >10.1.1.6410.1.1.6410.1.1.6410.1.1.64< Jan 5 12:51:11 nagiostest2 nrpe: is_an_allowed_host (AF_INET): host is in allowed host list! Jan 5 12:51:11 nagiostest2 nrpe: Error: (ERR_get_error_line_data = 336105671), Could not complete SSL handshake with 10.1.1.64: peer did not return a certificate Here is the important portions of my nrpe.cfg debug=1 ssl_cipher_list=ALL:!aNULL:!eNULL:!SSLv2:!LOW:!EXP:!RC4:!MD5:@STRENGTH ssl_version=TLSv1.1+ #ssl_cipher_list=ALL:!MD5:@STRENGTH #ssl_cipher_list=ALL:!MD5:@STRENGTH:@SECLEVEL=0 ssl_cipher_list=ALL:!aNULL:!eNULL:!SSLv2:!LOW:!EXP:!RC4:!MD5:@STRENGTH # SSL Certificate and Private Key Files ssl_cacert_file=/etc/nagios/ssl/ca.crt ssl_cert_file=/etc/nagios/ssl/star.mydomain.com.crt ssl_privatekey_file=/etc/nagios/ssl/star.mydomain.com.key # SSL USE CLIENT CERTS # This options determines client certificate usage. # Values: 0 = Don't ask for or require client certificates (default) # 1 = Ask for client certificates # 2 = Require client certificates ssl_client_certs=2 # Enables all SSL Logging ssl_logging=0xff Thank you for any help ahead of time!

Yesterday I upgraded a server from Debian 9 to Debian 10. This server is supervised with nagios. Since the upgrade, I get an alert, status Unknown saying : > "Volumegroup array03-0 wasn't valid or wasn't specified with "-v > Volumegroup", bye. false The service is VG baie03-0 usage, its command is check_nrpe!check_vgs_array03-0. The goal of this service is to generate an alert if storage on the array is almost full. check_nrpe command is standard : # 'check_NRPE' command definition define command{ command_name check_nrpe command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$ } If I'm not mistaken, it means that I have a check_vgs_array03-0 command in my /etc/nagios/nrpe.cfg on the supervised server. Let's look at it, here it is : > command[check_vgs_array03-0]=/usr/lib/nagios/plugins/check_vg_size -w > 20 -c 10 -v array03-0 If I just type this command on the supervised server, I have no errors, it works. > VG array03-0 OK Available space is 805 GB;| > array03-0=805GB;20;10;0;19155 I got the error if, for example, I type a volumegroup name that doesn't exist. check_vg_size plugin script goes like this : #!/bin/bash #check_vg_size #set -x # Plugin for Nagios # Written by M. Koettenstorfer (mko@lihas.de) # Some additions by J. Schoepfer (jsc@lihas.de) # Major changes into functions and input/output values J. Veverka (veverka.kuba@gmail.com) # Last Modified: 2012-11-06 # # Description: # # This plugin will check howmany space in volume groups is free # Nagios return codes STATE_OK=0 STATE_WARNING=1 STATE_CRITICAL=2 STATE_UNKNOWN=3 STATE_DEPENDENT=4 SERVICEOUTPUT="" SERVICEPERFDATA="" PROGNAME=$(basename $0) vgs_bin=/usr/bin/whereis -b -B /sbin /bin /usr/bin /usr/sbin -f vgs | awk '{ print $2 }' _vgs="$vgs_bin --units=g" bc_bin=/usr/bin/whereis -b -B /sbin /bin /usr/bin /usr/sbin -f bc | awk '{ print $2 }' exitstatus=$STATE_OK #default declare -a volumeGroups; novg=0; #number of volume groups allVG=false; #Will we use all volume groups we can find on system? inPercent=false; #Use percentage for comparison? unitsGB="GB" unitsPercent="%" units=$unitsGB ######################################################################## ### DEFINE FUNCTIONS ######################################################################## print_usage() { echo "Usage: $PROGNAME -w -c -v [-a] [-p]" echo "If '-a' and '-v' are specified: all volumegroups defined by -v will be ommited and the remaining groups which are found on system are checked" echo "If '-p' is specified: the warning and critical levels are represented as the percent space left on device" echo "" } print_help() { print_usage echo "" echo "This plugin will check how much space is free in volume groups" echo "usage: " exit $STATE_UNKNOWN } checkArgValidity () { # Check arguments for validity if [[ -z $critlevel || -z $warnlevel ]] # Did we get warn and crit values? then echo "You must specify a warning and critical level" print_usage exitstatus=$STATE_UNKNOWN exit $exitstatus elif [ $warnlevel -le $critlevel ] # Do the warn/crit values make sense? then if [ $inPercent != 'true' ] then echo "CRITICAL value of $critlevel GB is less than WARNING level of $warnlevel GB" print_usage exitstatus=$STATE_UNKNOWN exit $exitstatus else echo "CRITICAL value of $critlevel % is higher than WARNING level of $warnlevel %" print_usage exitstatus=$STATE_UNKNOWN exit $exitstatus fi fi } #Does volume group actually exist? volumeGroupExists () { local volGroup="$@" VGValid=$($_vgs 2>/dev/null | grep "$volGroup" | wc -l ) if [[ -z "$volGroup" || $VGValid = 0 ]] then echo "Volumegroup $volGroup wasn't valid or wasn't specified" echo "with \"-v Volumegroup\", bye." echo false return 1 else #The volume group exists echo true return 0 fi } getNumberOfVGOnSystem () { local novg=$($_vgs 2>/dev/null | wc -l) let novg-- echo $novg } getAllVGOnSystem () { novg=$(getNumberOfVGOnSystem) local found=false; for (( i=0; i /dev/null | head -n1 | awk -v name=$columnName ' BEGIN{} { for(i=1;i/dev/null | awk -v n=$cnFree '/[0-9]/{print $n}' | sed -e 's/[\.,\,].*//'`; fullspace=$_vgs $volumeName 2>/dev/null | awk -v n=$cnSize '/[0-9]/{print $n}' | sed -e 's/[\.,\,].*//'; if ( $inPercent ); then #Convert to Percents freespace="$(convertToPercent $freespace $fullspace)" fi } setExitStatus () { local status=$1 local volGroup="$2" local formerStatus=$exitstatus if [ $status -gt $formerStatus ] then formerStatus=$status fi if [ $status = $STATE_UNKNOWN ] ; then SERVICEOUTPUT="${volGroup}" exitstatus=$STATE_UNKNOWN return fi if [ "$freespace" -le "$critlevel" ] then SERVICEOUTPUT=$SERVICEOUTPUT" VG $volGroup CRITICAL Available space is $freespace $units;" exitstatus=$STATE_CRITICAL elif [ "$freespace" -le "$warnlevel" ] then SERVICEOUTPUT=$SERVICEOUTPUT"VG $volGroup WARNING Available space is $freespace $units;" exitstatus=$STATE_WARNING else SERVICEOUTPUT=$SERVICEOUTPUT"VG $volGroup OK Available space is $freespace $units;" exitstatus=$STATE_OK fi SERVICEPERFDATA="$SERVICEPERFDATA $volGroup=$freespace$units;$warnlevel;$critlevel" if [ $inPercent != 'true' ] ; then SERVICEPERFDATA="${SERVICEPERFDATA};0;$fullspace" fi if [ $formerStatus -gt $exitstatus ] then exitstatus=$formerStatus fi } checkVolumeGroups () { checkArgValidity for (( i=0; i &2 ;; esac done checkVolumeGroups echo $SERVICEOUTPUT"|"$SERVICEPERFDATA exit $exitstatus I I use another arg (another script) to the check_nrpe command, it works. for example : > root@nagiosserver:/usr/local/nagios# /usr/local/nagios/libexec/check_nrpe > -H srv-supervised04 -c check_load OK - load average: 3.79, 2.99, 1.83|load1=3.790;25.000;30.000;0; load5=2.990;20.000;25.000;0; load15=1.830;15.000;20.000;0; VG array03-0 does exist : > root@srv-supervised04:/usr/lib/nagios/plugins# vgdisplay --- Volume group --- VG Name array03-0 System ID Format > lvm2 Metadata Areas 1 Metadata Sequence No 34 VG Access > read/write VG Status resizable MAX LV 0 > Cur LV 5 Open LV 4 Max PV > 0 Cur PV 1 Act PV 1 VG Size > 4903887 Alloc PE / Size 4697600 / 206287 / OgzAMF-DGbW-3t3L-Wk7k-gY1g-s6fH-zYEKad So. VG does exist. The check_vg_size plugin works when used locally, the check_nrpe command works from the nagios server when used with another plugin but check_vg_size doesn't work from nagios server. Error message is apparently that array03-0 doesn't exist while it does. I haven't changed anything from all the files. It appeared with Debian update from 9 to 10 (during the installation, I decided to keep my nrpe.cfg modified file). Anyone knows where it can come from ? Debian version ? New bash version maybe ? An incompatibility between the nagios server (still Debian 9) and the supervised one (Debian 10) ?

I have a bash script that runs hostapd_cli all_sta, and the script executes successfully from the command line under both jessie and stretch. The script also works when run under sudo on jessie but not on stretch. On stretch the command times out with the error 'STA-FIRST' command timed out. When I invoke hostapd_cli under strace I see that it opens a socket file under /tmp: bind(3, {sa_family=AF_UNIX, sun_path="/tmp/wpa_ctrl_13552-1"}, 110) = 0 connect(3, {sa_family=AF_UNIX, sun_path="/var/run/hostapd/wlan1"}, 110) = 0 As a test I temporarily modified the script and added a line:

echo "this is a test" >/tmp/test 2>/root/error

When the modified script runs under sudo, the file in /tmp is not created and no error is written to /tmp/error. On my system, /tmp is not a tmpfs, just a plain old directory under / on an ext3 filesystem. So root is unable to create a file under /tmp and there is ample space. # df -h /tmp Filesystem Size Used Avail Use% Mounted on /dev/sdb2 6.7G 5.1G 1.4G 80% / And an ls -ld /tmp gives: # ls -ld /tmp drwxrwxrwt 9 root root 4096 Jul 27 23:50 /tmp/ If I can figure out why /tmp can't be written to, I believe the hostapd_cli command will work. What could be happening here?

I have an nvr system that recording video surveillance into a file server (Debian). I made a Nagios plugin to check if the NVR system is recording correctly and send me a notification when it stops doing that. The issue is I'm using a find command: find /srv/unifi-video/videos/ -name '*.ts' -mmin -10 | wc -l and since it's checking through 400 Gb+ of files Nagios keeps timing out and sending "NRPE Socket timed out" messages. Is it possible to make the find command to search only for the files created in the passed 10 minutes and not only the whole folder ?

I'm learning a little bit of nagios and unix(buster), and im getting an error related with monitoring CPU LOAD and MEMORY USAGE The feedback I get from the monitor is connect to address 192.168.1.94 and port 12489: Connection refused could not fetch information from server So I went to the client machine and ran netstat -an, and the port doesnt seem to be listening. I tried to add some rules on iptables, did some rules for port 12489 on TCP the port was there on "ACCEPT tcp -- anywhere anywhere tcp dpt:12489" sudo iptables-save what am I missing? the machines are in the same local network am im missing some configuration or plugin? Thank you

I have lots of scripts, usually they start with a shebang and /usr/bin/env and the required interpreter (for example "#!/usr/bin/env perl"). This works fine since many years, but for some reason I don't understand I have one script on one FreeBSD machine where this breaks sudo:

% cat test.pl
#!/usr/bin/env perl
system( "id" );
exit 0;

Executing this as user nagios works fine. Executing this with sudo as user nagios also works fine. But, executing this through nrpe daemon from monitoring server, where the nrpe is running as user nagios and using sudo as command_prefix it exits with error code 3. Since nrpe doesn't show any reasons, but just the exit code, I have no clue why this doesn't work. (Yes, sudo seems to be configured correctly to allow /usr/bin/env and test.pl, as it works on commandline)

nrpe: Running command: /usr/local/bin/sudo /usr/local/etc/nagios/test.pl
nrpe: Command completed with return code 3 and output: 
nrpe: Return Code: 3, Output: NRPE: Unable to read output

Yes, I could change the shebang string to /usr/local/bin/perl, which then works with sudo through nrpe, but the script is intended to be generic for different OS types. So, any idea what I'm missing here?

This script I have here works locally just fine: #! /bin/bash volts=sudo vcgencmd measure_volts core|sed 's/volt=\([0-9\.]*\)V/\1/' echo -n "BCM2835 SoC Voltage is ${volts}V " echo "| volts=$volts;1.5;1.5;0;1.5" However if Nagios tries to get the information it only gets "BCM2835 SoC Voltage is V" as if the variable was not defined. There are also other plugins which pull the information from files and it works. So I managend to write the information in a temp file and write it back into the variable. #! /bin/bash sudo vcgencmd measure_volts core|sed 's/volt=\([0-9\.]*\)V/\1/'>/tmp/volts volts=$(