Nagios Support Forum

Hello,

I have a script which is responsible for executing multiple commands to check cluster behaviour like (pcs status). this script is installed on remote servers and it works fine locally. but when I try to execute this script via check_nrpe from Nagios server the scripts run without executing the "pcs status " command.

I think it's related to some permission.

can you please help?

Try this, edit the nrpe.cfg file on the remote host and change the following from

debug=0

to Save the change and restart the NRPE agent.

Check the /var/log/messages file for any errors when the plugin is ran on the remote system and post them here.

Also, post the command that you defined in the nrpe.cfg file on the remote server and the script you are trying to run so we can see what it is doing.

One more thing, the NRPE agent runs the commands as the nagios user so make sure it can run the applications needed to gather the data and that is can find the commands on the path.

the client output /var/log/messages when executing the NRPE script from Nagios server :

Feb 16 08:09:21 dascsdbo00001b nrpe[14016]: CONN_CHECK_PEER: checking if host is allowed: 10.1.23.222 port 20100
Feb 16 08:09:21 dascsdbo00001b nrpe[14016]: is_an_allowed_host (AF_INET): is host >10.1.23.222< an allowed host >10.1.23.222<
Feb 16 08:09:21 dascsdbo00001b nrpe[14016]: is_an_allowed_host (AF_INET): is host >10.1.23.222< an allowed host >10.1.23.222<
Feb 16 08:09:21 dascsdbo00001b nrpe[14016]: is_an_allowed_host (AF_INET): host is in allowed host list!
Feb 16 08:09:21 dascsdbo00001b nrpe[14017]: WARNING: my_system() seteuid(0): Operation not permitted
Feb 16 08:09:21 dascsdbo00001b dbus[1097]: [system] Activating service name='org.fedoraproject.Setroubleshootd' (using servicehelper)
Feb 16 08:09:21 dascsdbo00001b dbus[1097]: [system] Successfully activated service 'org.fedoraproject.Setroubleshootd'
Feb 16 08:09:21 dascsdbo00001b setroubleshoot: SELinux is preventing /usr/bin/python2.7 from execute access on the file /usr/sbin/corosync. For complete SELinux messages run: sealert -l 147ebee6-e792-44a6-b763-7ec6c5992f0a
Feb 16 08:09:21 dascsdbo00001b python: SELinux is preventing /usr/bin/python2.7 from execute access on the file /usr/sbin/corosync.#012#012***** Plugin catchall (100. confidence) suggests **************************#012#012If you believe that python2.7 should be allowed execute access on the corosync file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'pcs' --raw | audit2allow -M my-pcs#012# semodule -i my-pcs.pp#012
Feb 16 08:09:22 dascsdbo00001b setroubleshoot: SELinux is preventing check_cluster.s from getattr access on the file /usr/bin/sudo. For complete SELinux messages run: sealert -l eec466b1-71b7-4d18-b8a6-545868e07d17
Feb 16 08:09:22 dascsdbo00001b python: SELinux is preventing check_cluster.s from getattr access on the file /usr/bin/sudo.#012#012***** Plugin catchall_boolean (89.3 confidence) suggests ******************#012#012If you want to allow nagios to run sudo#012Then you must tell SELinux about this by enabling the 'nagios_run_sudo' boolean.#012#012Do#012setsebool -P nagios_run_sudo 1#012#012***** Plugin catchall (11.6 confidence) suggests **************************#012#012If you believe that check_cluster.s should be allowed getattr access on the sudo file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'check_cluster.s' --raw | audit2allow -M my-checkclusters#012# semodule -i my-checkclusters.pp#012
Feb 16 08:09:22 dascsdbo00001b setroubleshoot: SELinux is preventing check_cluster.s from getattr access on the file /usr/bin/sudo. For complete SELinux messages run: sealert -l eec466b1-71b7-4d18-b8a6-545868e07d17
Feb 16 08:09:22 dascsdbo00001b python: SELinux is preventing check_cluster.s from getattr access on the file /usr/bin/sudo.#012#012***** Plugin catchall_boolean (89.3 confidence) suggests ******************#012#012If you want to allow nagios to run sudo#012Then you must tell SELinux about this by enabling the 'nagios_run_sudo' boolean.#012#012Do#012setsebool -P nagios_run_sudo 1#012#012***** Plugin catchall (11.6 confidence) suggests **************************#012#012If you believe that check_cluster.s should be allowed getattr access on the sudo file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'check_cluster.s' --raw | audit2allow -M my-checkclusters#012# semodule -i my-checkclusters.pp#012


the command that you defined in the nrpe.cfg:
command[check_cluster_env]=/usr/lib64/nagios/plugins/check_cluster.sh $ARG1$

Selinux is enabled on the remote server and is blocking the plugin from running.
In the output from the /var/log/messages file, it ezplaigns that is it blocked and it has the commands to enable it to by-pass selinux.
Here are the commands to bypass selinux.

Run them as root on the remote server.
Then see if you can run the NRPE command from the Nagios server.

If it does not run, check the /var/log/messages file for any new log entries for selinux blocking the plugin.
Run the commands to bypass it until the plugin runs.

Thanks for your reply,
after applying all SElinux commands, still, the NRPE script doesn't work well,

The output of /var/log/messages on the client-side is :
Feb 16 19:20:56 dascsdbo00001b nrpe[14227]: CONN_CHECK_PEER: checking if host is allowed: 10.1.23.222 port 43245
Feb 16 19:20:56 dascsdbo00001b nrpe[14227]: is_an_allowed_host (AF_INET): is host >10.1.23.222< an allowed host >10.1.23.222<
Feb 16 19:20:56 dascsdbo00001b nrpe[14227]: is_an_allowed_host (AF_INET): is host >10.1.23.222< an allowed host >10.1.23.222<
Feb 16 19:20:56 dascsdbo00001b nrpe[14227]: is_an_allowed_host (AF_INET): host is in allowed host list!
Feb 16 19:20:56 dascsdbo00001b nrpe[14228]: WARNING: my_system() seteuid(0): Operation not permitted
Feb 16 19:20:56 dascsdbo00001b systemd: Started Session c164372 of user root.
Feb 16 19:20:56 dascsdbo00001b dbus[1097]: [system] Activating service name='org.fedoraproject.Setroubleshootd' (using servicehelper)
Feb 16 19:20:57 dascsdbo00001b dbus[1097]: [system] Successfully activated service 'org.fedoraproject.Setroubleshootd'
Feb 16 19:20:57 dascsdbo00001b setroubleshoot: Exception during AVC analysis: must be encoded string without NULL bytes, not str
Feb 16 19:21:00 dascsdbo00001b setroubleshoot: Exception during AVC analysis: must be encoded string without NULL bytes, not st

Post the full nrpe.cfg file and the /usr/lib64/nagios/plugins/check_cluster.sh script so we can look at it.

Run this as root on the remote system and post the output. If the plugin requires root permissions to run, try doing this.

Edit the /etc/sudoers file and add the following entry You may need to add a line to the pcs command in the sudoers file as well.
Here is an example. Make sure you update the path to the pcs command. Next edit the nrpe.cfg file and add sudo to it. Save the change and restart the nrpe service and see if that helps.

The output of (ps -ef --cols=300 |grep nrpe) on the client side :
nrpe 3799 1 0 20:09 ? 00:00:00 /usr/sbin/nrpe -c /etc/nagios/nrpe.cfg -f
root 57798 57036 0 20:51 pts/1 00:00:00 grep --color=auto nrpe
i added nrpe to sudors as you suggested, but now when call the script from Nagios server using NRPE :

[root@nagios libexec]# ./check_nrpe -H XX.XX.XX.XX -c check_cluster_env -a 'Stonith'
NRPE: Unable to read output


attached nrpe.cfg and check_cluster.sh scripts

Login to the remote server and change to the nrpe user by running the following. Then run this to see what the output of the plugin is when it runs. Post all of the output.

Please note that nrpe is no login user
nrpe996:992:NRPE user for the NRPE service:/var/run/nrpe:/sbin/nologin

so we cannot switch to that user


- so i did the following:
sudo -s -u nrpe
- NOW IAM nrpe user

- The output of (bash -x /usr/lib64/nagios/plugins/check_cluster.sh Stonith) is:
bash-4.2$ bash -x /usr/lib64/nagios/plugins/check_cluster.sh Stonith
+ CRM=/usr/sbin/pcs
+ CRMV=/usr/sbin/crm_verify
+ STATE_OK=0
+ STATE_WARNING=1
+ STATE_CRITICAL=2
+ STATE_UNKNOWN=3
+ '[' 1 -lt 1 ']'
++ /usr/sbin/pcs config show
++ grep -A1 'Corosync Nodes:'
++ tail -n1
Error: error running crm_mon, is pacemaker running?
+ nodelist=
+ case $1 in
+ checkstonith
++ sudo /usr/sbin/pcs stonith show
++ grep -i Started
++ wc -l

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

#1) Respect the privacy of others.
#2) Think before you type.
#3) With great power comes great responsibility.


- the Output of (echo $?) is:
1

- the output of (/usr/sbin/pcs stonith show)

bash-4.2$ /usr/sbin/pcs stonith show
Error: unable to get cluster status from crm_mon

Error: cluster is not available on this node

Since the plugin is using a shell, the nrpe user has to be able to login.

Change this from to Next, you need to figure out why you cannot get the Cluster status when running this.

/usr/sbin/pcs stonith show
Error: unable to get cluster status from crm_mon
Error: cluster is not available on this node