SMART by Zabbix agent 2 Issue

[Gomo]

Hello all,

I have Zabbix server setup on my Ubuntu 22.04.4 LTS VM which queries other VMs and systems to gather data and alerts. This is all working fine.
One of the machines on which I have Zabbix agent installed on is a Proxmox hypervisor (debian 12). Using "Linux by Zabbix agent" template I am getting a lot of data collected (all working well). Now, I wanted to also gather SMART values of the drives which are installed on that system. So I went ahead and added additional template for that host "SMART by Zabbix agent 2" (following the steps described here https://www.zabbix.com/integrations/smart). I am not sure why but I am getting following error:

Cannot fetch data.: failed to execute smartctl: failed to get combined output of stdout and stderr for smartctl process: waitid: no child processes.

I have a feeling this might be related to "zabbix ALL=(ALL) NOPASSWD:/usr/sbin/smartctl" part not working properly.
Here's how my "visudo" file looks like:




Would appreciate if someone could point me to a right direction!
Thank you.

[Gomo]

Anyone? can't be that I am only one with this issue :/

[Gomo]

bump .. Anyone?

[Markku]

Works here (in a VM, just doesn't apparently return any disks).

What does sudo smartctl -V return on the Debian host?

Markku

[Gomo]

Works here (in a VM, just doesn't apparently return any disks).

What does sudo smartctl -V return on the Debian host?

Markku

This is the output:

root@magnetar:~$ sudo smartctl -V
smartctl 7.3 2022-02-28 r5338 [x86_64-linux-6.8.4-3-pve] (local build)
Copyright (C) 2002-22, Bruce Allen, Christian Franke, www.smartmontools.org

smartctl comes with ABSOLUTELY NO WARRANTY. This is free
software, and you are welcome to redistribute it under
the terms of the GNU General Public License; either
version 2, or (at your option) any later version.
See https://www.gnu.org for further details.

smartmontools release 7.3 dated 2022-02-28 at 16:33:40 UTC
smartmontools SVN rev 5338 dated 2022-02-28 at 16:34:26
smartmontools build host: x86_64-pc-linux-gnu
smartmontools build with: C++11, GCC 12.2.0
smartmontools configure arguments: [hidden in reproducible builds]
reproducible build SOURCE_DATE_EPOCH: 1686925941 (2023-06-16 16:32:21)
root@magnetar:~$

[Markku]

Thanks, so at least smartctl looks like it should be executable. I found the error message "failed to execute smartctl" in here: https://github.com/zabbix/zabbix/blo.../smart.go#L166

Do you have apparmor or something else that could prevent zabbix user from executing smartctl?

Markku

[Gomo]

Thanks, so at least smartctl looks like it should be executable. I found the error message "failed to execute smartctl" in here: https://github.com/zabbix/zabbix/blo.../smart.go#L166

Do you have apparmor or something else that could prevent zabbix user from executing smartctl?

Markku

To be honest I have never heard of "apparmor", but now that I checked, it looks like Proxmox (debian 12) is using it by default.

root@magnetar:~$ systemctl status apparmor
● apparmor.service - Load AppArmor profiles
     Loaded: loaded (/lib/systemd/system/apparmor.service; enabled; preset: enabled)
     Active: active (exited) since Sun 2024-05-26 18:07:15 CEST; 1 week 0 days ago
       Docs: man:apparmor(7)
             https://gitlab.com/apparmor/apparmor/wikis/home/
    Process: 5444 ExecStart=/lib/apparmor/apparmor.systemd reload (code=exited, status=0/SUCCESS)
   Main PID: 5444 (code=exited, status=0/SUCCESS)
        CPU: 2.352s

May 26 18:07:14 magnetar systemd[1]: Starting apparmor.service - Load AppArmor profiles...
May 26 18:07:14 magnetar apparmor.systemd[5444]: Restarting AppArmor
May 26 18:07:14 magnetar apparmor.systemd[5444]: Reloading AppArmor profiles
May 26 18:07:15 magnetar systemd[1]: Finished apparmor.service - Load AppArmor profiles.
root@magnetar:~$

Any idea what needs to be done in order to grant zabbix user necessary permission?

[Markku]

Unfortunately no idea

Markku

[Gomo]

I disabled "apparmor" and the issue persists, sooo, it can't be caused by that.

[Markku]

Are you still receiving the exact same error message ("failed to execute smartctl") even after disabling apparmor?

Does "sudo -u zabbix /usr/sbin/smartctl" work?

Markku

[Gomo]

Are you still receiving the exact same error message ("failed to execute smartctl") even after disabling apparmor?

Does "sudo -u zabbix /usr/sbin/smartctl" work?

Markku

Yes, it was showing the same error with "apparmor" disabled / not running.

Here's the result of command you mentioned

[Gomo]

Bump.... anyone?

[Markku]

How about

sudo -u zabbix sudo /usr/sbin/smartctl /dev/sda

Markku

[Gomo]

How about

sudo -u zabbix sudo /usr/sbin/smartctl /dev/sda

Markku

It was performed, see second command in the previous screenshot.

[Markku]

Note the second "sudo" in the command

[mdella]

Yes, it was showing the same error with "apparmor" disabled / not running.

Here's the result of command you mentioned

So whats happening there is that the "zabbix" user is trying to execute the smartctl command which is a root privledged command only. The above suggestion from Markku should work for you on your machine. Typically what this means is that your zabbix system was not granted access to the /dev/sd? devices application. If his example does *not* work, then the problem is going to be in your /etc/sudoers file (either there is a hidden typo, located in the wrong order, etc.

Additionally, I see you used the "@includedir" function. If your sudo is 1.9.1 or earlier, that wont work and would need to be the original "#includedir" to get your zabbix entry.

Lastly, you have "two" zabbix entries, one in the include dir and one at the end of your /etc/sudoers file. You have to eliminate one of those or you have a conflict.

Marcos