NRPE agent not working on Oracle Linux 7

[hkang]

The log file is attached. Can you view it?

install.log

[jolson]

Lets make sure your nrpe binary exists:

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ls -l /usr/sbin/nrpe

Is there an appropriate entry in /etc/services?

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grep 5666 /etc/services

The following entry should appear at the end of /etc/services:

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# Nagios services
nrpe    5666/tcp

Please verify that the above entry exists. If it does not, add it and restart xinetd.

A couple of other things to check on:

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systemctl status xinetd -l

Check open ports:

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ss -nap | grep 5666

Try running the binary without xinetd:

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/usr/sbin/nrpe -c /usr/local/nagios/etc/nrpe.cfg --inetd

Check on ports again:

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ss -nap | grep 5666

[hkang]

The output of those commands:

1. ls -l /usr/sbin/nrpe
ls: cannot access /usr/sbin/nrpe: No such file or directory

2. grep 5666 /etc/services
###UNAUTHORIZED USE: Port 5666 used by SAIC NRPE############
nrpe 5666/tcp

3. systemctl status xinetd -l
xinetd.service - Xinetd A Powerful Replacement For Inetd
Loaded: loaded (/usr/lib/systemd/system/xinetd.service; enabled)
Active: active (running) since Thu 2016-01-07 02:00:43 CST; 1 day 11h ago
Process: 1424 ExecStart=/usr/sbin/xinetd -stayalive -pidfile /var/run/xinetd.pid $EXTRAOPTIONS (code=exited, status=0/SUCCESS)
Main PID: 1435 (xinetd)
CGroup: /system.slice/xinetd.service
└─1435 /usr/sbin/xinetd -stayalive -pidfile /var/run/xinetd.pid

Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing discard
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing discard
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing echo
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing echo
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing tcpmux
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing time
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: removing time
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: Must specify a server in nrpe
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: xinetd Version 2.3.15 started with libwrap loadavg labeled-networking options compiled in.
Jan 07 02:00:43 calendar-310-uaex-edu xinetd[1435]: Started working: 1 available service

4. ss -nap | grep 5666
No output

5. /usr/sbin/nrpe -c /usr/local/nagios/etc/nrpe.cfg --inetd
-bash: /usr/sbin/nrpe: No such file or directory

[hkang]

It seems that the nrpe binary doesn't exist. How can I add it?

[jolson]

Does the binary exist anywhere?

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find / -name nrpe -type f

It should exist somewhere - either in the directory where you installed nrpe from (typically /tmp) or somewhere else on the system. Be sure that xinetd knows exactly what to point to.

If the NRPE binary is in /tmp, be sure to copy it to somewhere sane (/usr/local/nagios/bin/ for instance).

Jesse

[hkang]

There are two nrpe files on this server. But I don't think either of them is what we are looking for, since they are not binary files.

1. cat /etc/xinetd.d/nrpe
# default: on
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
flags = REUSE
socket_type = stream
port = 5666
wait = no
user = nagios
group = nagios
# server = /usr/local/nagios/bin/nrpe
server = /usr/sbin/nrpe
server_args = -c /usr/local/nagios/etc/nrpe.cfg --inetd
log_on_failure += USERID
disable = no
only_from = 10.200.160.93 127.0.0.1
}

2. cat /tmp/nagjos/linux-nrpe-agent/subcomponents/nrpe/nrpe-2.15/package/solaris/pkg/nrpe
#!/sbin/sh
#

NRPE=/opt/nagios/bin/nrpe
CFGFILE=/etc/nagios/nrpe.cfg
PIDFILE=/var/run/nrpe.pid

case $1 in
'start')
$NRPE -c $CFGFILE -d
;;

'restart')
if [ -f "$PIDFILE" ]; then
/usr/bin/kill -HUP `/usr/bin/cat $PIDFILE`
fi
;;

'stop')
if [ -f "$PIDFILE" ]; then
/usr/bin/kill `/usr/bin/cat $PIDFILE`
/bin/rm -f $PIDFILE
fi
;;

*)
echo "Usage: $0 { start | restart | stop }"
exit 1
;;
esac

exit $?

[hkang]

I found a nrpe binary file on another box which is running CentOS 6.7 and has nrpe agent working fine on it. Can I copy that file to this OL 7 box?

[rkennedy]

Taking a step back, I reviewed your install.log. It appears you're missing libmcrypt

Can you run the following command, and post the output?

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rpm -qa|grep libmcrypt

Regarding copying the file - this may work at times, but usually not. As the binaries are compiled based off of your environment you could run into weird issues.

[hkang]

No output for "rpm -qa|grep libmcrypt".

[jolson]

You'll likely have to install the libmcrypt and libmcrypt-devel libraries, give the following a try.

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yum install libmcrypt libmcrypt-devel

Let us know if there are any problems with the above. After you've installed the libraries, attempt installing NRPE again and see if the binary generates appropriately this time.

Jesse