Getting error ssl_err != 5 when trying to do check_nrpe

[andrewleung01]

Hi nagios support,

Recently I am working on a task which migrates our nagios configurations from a old centos to a new rhel8 VM.

Everything works fine on the new rhel8 VM, except I notice some of the hosts which nagios monitors their checks are failing.

I looked further and found it was due to this error.

CHECK_NRPE: (ssl_err != 5) Error - Could not complete SSL handshake with 10.138.52.117: 1

I then try to run the nrpe check on the nagios VM and got the same error.

nagios@ulpmas0897 : /usr/local/nagios/libexec # ./check_nrpe -H 10.138.52.117
CHECK_NRPE: (ssl_err != 5) Error - Could not complete SSL handshake with 10.138.52.117: 1

Any idea?

Please note all our target hosts which our nagios monitors are on RHEL.

Thanks.

Regards,
Andrew

[vtrac]

Hi Andrew,
How are you doing?

What is the OS for the "10.138.52.117" (your remote NRPE agent)?
Was this "10.138.52.117" also has OS upgraded?

Also, on your Nagios XI command prompt, please run below commands and post outputs:

Code: Select all

rpm -qa | grep nrpe

ls -l /usr/local/nagios/libexec/check_nrpe

/usr/local/nagios/libexec/check_nrpe -V

Please also share your "/usr/local/nagios/etc/nrpe.cfg" file.


Best Regards,
Vinh

[andrewleung01]

Hi Vinh,

Thanks for getting me back.

We haven't upgraded any of the target hosts lately.

Just further background information of this, our DB Nagios is monitoring hundreds of databases across our organisation.

After I migrated the monitoring configurations from our old to the new RHEL8 VM I won't say all but many of them are having this issue. I have checked a few of them and seems to me the pattern might not depend on the version of the OS on the target side.

For instance, host 10.138.52.117 is having this issue, and this is its version of RHEL.

$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.9 (Maipo)

And another host 10.138.52.158 which does not have this issue, and this is the version of its RHEL.

$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.9 (Maipo)

As per your request please find the output of the commands which you need below.

root@ulpmas0897 : /root # rpm -qa | grep nrpe
root@ulpmas0897 : /root # ls -l /usr/local/nagios/libexec/check_nrpe
-rwxrwxr-x. 1 apache nagios 134K Jul 21 14:34 /usr/local/nagios/libexec/check_nrpe*
root@ulpmas0897 : /root # /usr/local/nagios/libexec/check_nrpe -V
NRPE Plugin for Nagios
Version: 4.0.3

root@ulpmas0897 : /root #

A copy of the nrpe.cfg on our nagiosxi VM is attached.

Please let me know if further information is needed. Thanks again.

Regards,
Andrew

[andrewleung01]

Hi Vinh, I have sent a reply earlier to your query. Please let me know if you cannot see it.

Thanks.

Regards,
Andrew

[andrewleung01]

Hi Vinh,

In case you also need it I also have the two files of nrpe cfg attached.

One of them belongs to the VM which we don't have the nrpe issue when running check_nrpe from our DB Nagios VM., and the other one belongs to the one we have.

Thanks.

Regards,
Andrew

[vtrac]

Hi Andrew,
Hope you are having a great day!! ...

Looking at those "nrpe.cfg" config files (between the good and the issued one), both looks to be the exactly the same.

I am thinking the issue is with the "check_nrpe" on your Nagios XI machine (VM).

I have attached a "check_npre.tar" file, please download the tar file to "/tmp", then as "root" ... please do:

Code: Select all

cd /tmp
tar -xvf check_nrpe.tar

mv -f /usr/local/nagios/libexec/check_nrpe /usr/local/nagios/libexec/check_nrpe.bak
cp -f -p check_nrpe /usr/local/nagios/libexec/

Now, please try the below command on your Nagios XI command prompt:

Code: Select all

/usr/local/nagios/libexec/check_nrpe  -H 10.138.52.117

Please let me know how it goes ...

If you are still having issue, please also run the below command on your Nagios XI and post outputs:

Code: Select all

nmap -Pn -p5666 10.138.52.117

Best Regards
Vinh