Unable to install nrpe-agent on server joined to ad domain

[WillemDH]

hello,

I seem to have issues installing the nrpe-agent on a CentOS 7 system which has been joined to our ad domain with realmd / SSSD.

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Prerequisites installed OK
RESULT=0
Running './2-usersgroups'...
Adding users and groups...
useradd: user 'nagios' already exists
useradd: user 'nagios' already exists
ERROR: User 'nagios' was not created - exiting.
RESULT=1

===================
INSTALLATION ERROR!
===================
Installation step failed - exiting.
Check for error messages in the install log (install.log).

If you require assistance in resolving the issue, please include install.log
in your communications with Nagios XI technical support.

The script that failed was: './2-usersgroups'
[root@srvdockerqa01 linux-nrpe-agent]# updatedb
[root@srvdockerqa01 linux-nrpe-agent]# ./fullinstall
============================
Nagios Linux Agent Installer
============================

This script will install the Nagios Linux Agent by executing all necessary
sub-scripts.

IMPORTANT: This script should only be used on a clean installed system:

   RedHat Enterprise, CentOS, Fedora, or Oracle
   OpenSUSE or SUSE Enterprise
   Ubuntu or Debian

Do NOT use this on a system running any other distro or that
does not allow additional package installation.

Do you want to continue? [Y/n] Y
Proceeding with installation...
Running './0-repos'...
Repos already configured - exiting.
RESULT=0
Running './1-prereqs'...
Prereqs already installed - skipping...
RESULT=0
Running './2-usersgroups'...
Adding users and groups...
useradd: user 'nagios' already exists
groupadd: group 'nagios' already exists
useradd: user 'nagios' already exists
groupadd: group 'nagcmd' already exists
ERROR: User 'nagios' was not created - exiting.
RESULT=1

===================
INSTALLATION ERROR!
===================
Installation step failed - exiting.

it somehow complains a nagios user already exists, but in fact it doesn't. It is not in /etc/passwd
When I try to

Code: Select all

userdel nagios
userdel: cannot remove entry 'nagios' from /etc/passwd

Any hint how to get the nrpe-agent installed on this system? This is the procedure I used to add the CentOS 7 server to the domain: http://outsideit.net/realmd-and-sssd-ad-authentication/
There is no user 'nagios' in our ad domain, so I'm not sure what's going wrong.

Grtz

[hsmith]

hello,

I seem to have issues installing the nrpe-agent on a CentOS 7 system which has been joined to our ad domain with realmd / SSSD.

Code: Select all

Prerequisites installed OK
RESULT=0
Running './2-usersgroups'...
Adding users and groups...
useradd: user 'nagios' already exists
useradd: user 'nagios' already exists
ERROR: User 'nagios' was not created - exiting.
RESULT=1

===================
INSTALLATION ERROR!
===================
Installation step failed - exiting.
Check for error messages in the install log (install.log).

If you require assistance in resolving the issue, please include install.log
in your communications with Nagios XI technical support.

The script that failed was: './2-usersgroups'
[root@srvdockerqa01 linux-nrpe-agent]# updatedb
[root@srvdockerqa01 linux-nrpe-agent]# ./fullinstall
============================
Nagios Linux Agent Installer
============================

This script will install the Nagios Linux Agent by executing all necessary
sub-scripts.

IMPORTANT: This script should only be used on a clean installed system:

   RedHat Enterprise, CentOS, Fedora, or Oracle
   OpenSUSE or SUSE Enterprise
   Ubuntu or Debian

Do NOT use this on a system running any other distro or that
does not allow additional package installation.

Do you want to continue? [Y/n] Y
Proceeding with installation...
Running './0-repos'...
Repos already configured - exiting.
RESULT=0
Running './1-prereqs'...
Prereqs already installed - skipping...
RESULT=0
Running './2-usersgroups'...
Adding users and groups...
useradd: user 'nagios' already exists
groupadd: group 'nagios' already exists
useradd: user 'nagios' already exists
groupadd: group 'nagcmd' already exists
ERROR: User 'nagios' was not created - exiting.
RESULT=1

===================
INSTALLATION ERROR!
===================
Installation step failed - exiting.

it somehow complains a nagios user already exists, but in fact it doesn't. It is not in /etc/passwd
When I try to

Code: Select all

userdel nagios
userdel: cannot remove entry 'nagios' from /etc/passwd

Any hint how to get the nrpe-agent installed on this system? This is the procedure I used to add the CentOS 7 server to the domain: http://outsideit.net/realmd-and-sssd-ad-authentication/
There is no user 'nagios' in our ad domain, so I'm not sure what's going wrong.

Grtz

Hi Willem,

I just installed this on a fresh CentOS 7 machine following your instructions ( nice guide, btw )

It chimed at me that the user and group already existed, however it did not abort the script.

It in fact made the user and groups just fine...

You checked the actual files themselves to see if they are in there?

What happens if you edit out the './2-usersgroups' from the ./fullinstall file?

[WillemDH]

Hey,

This machine I was trying to install the nrep agent on is actually also a very new system. It has been used for about three weeks to test Docker containers on. In my case it did abort the script. I check and could not find any nagios user. (didn't check groups) What do you mean with

You checked the actual files themselves to see if they are in there?

I will try to edit out the './2-usersgroups' from the ./fullinstall file tomorrow, but I fear, as the user does not exist, the rest of the script will fail too somehow. I'll let you know how it goes.

Grtz

Willem

[ssax]

Just for good measure, please post the output of these commands:

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grep nag /etc/group
grep nag /etc/passwd

I was unable to replicate it as well, what does your /etc/nsswitch.conf say for passwd and group?

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grep "passwd\|group" /etc/nsswitch.conf

You could always manually add the /etc/passwd and /etc/group entries and then you can just run this command in the linux-nrpe-agent install directory to skip user/group creation:

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touch installed.usersgroups

[WillemDH]

Before using installed.usersgroups:

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grep nag /etc/group
nagios:x:1002:nagios
nagcmd:x:1003:nagios

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grep nag /etc/passwd

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grep "passwd\|group" /etc/nsswitch.conf
#passwd:    db files nisplus nis
#group:     db files nisplus nis
passwd:     files sss
group:      files sss
#initgroups: files
netgroup:   files sss

After creating installed.usersgroups I was able to continue the installation.

I seem to have one more issue, I would think it has something to do with systemctl, as I cloned the services from a CentOS 6 server.

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/usr/local/nagios/libexec/check_nrpe -H server -t 120 -c check_init_service -a 'sshd'
OUTPUT: NRPE: Unable to read output

Thanks.

[tgriep]

Can you run the check_init_service command on the remote system and get a valid output?

The check_nrpe plugin returns "NRPE: Unable to read output"
This error indicates that the command that was run by the NRPE daemon did not return any character output.
This could be an indication of the following problems:
– An incorrectly defined command line in the command definition. Verify that the command definition in your
NRPE configuration file is correct.
– The plugin that is specified in the command line is malfunctioning. Run the command line manually to make
sure the plugin returns some kind of text output.

[WillemDH]

Tom,

This is the result of the check on this particular CentOS 7 system

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/usr/local/nagios/libexec/check_init_service sshd
Redirecting to /bin/systemctl status  sshd.service
sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled)
   Active: active (running) since Tue 2015-08-04 11:09:01 CEST; 1 months 3 days ago
 Main PID: 1269 (sshd)
   CGroup: /system.slice/sshd.service
           └─1269 /usr/sbin/sshd -D

The same check on a CentOS 6 system:

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 /usr/local/nagios/libexec/check_init_service sshd
openssh-daemon (pid  1415) is running...

Grtz

Willem

[tgriep]

The output for Centos7 isn't compatible for that check. I found this replacement if you would like to try this instead.
https://exchange.nagios.org/directory/P ... ce/details

[tgriep]

Actually, you can make the old command work if you remove the sudo from the check_init_service test.

Edit /usr/local/nagios/etc/nrpe.cfg file and change this from

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command[check_init_service]=sudo /usr/local/nagios/libexec/check_init_service $ARG1$

to

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command[check_init_service]=/usr/local/nagios/libexec/check_init_service $ARG1$

Save the file and restart xinetd and see if that works for you.

[WillemDH]

Tom,

That did the trick. Please close this thread.

Grtz and tx.

Willem