External Check works fine only in zabbix server

[sergioyy]

I'm beginner user of Zabbix, and I'm trying to verify if a service is running on linux machine (other than zabbix server).

I created a script (zbx_service_check.sh) on /usr/lib/zabbix/externalscripts.
(I'm using postfix to test)

#!/bin/sh -x
service="postfix"
status=`/usr/sbin/service $service status`
if echo "$status" |grep -q "Active: active"; then
echo 0
else
echo 1
fi
fi

I created an item and a trigger (using expression {zabbix-lab:zbx_service_check.sh.last()}<>0 )

When I test it on Zabbix server, this works fine (I stop and start postfix using systemctl command and I got different values on "Latest data")

I configure same item and trigger on other server to be verifyied.
But, when I try to check other server, it is not work. I stop and start postfix on monitored server, but zabbix server only shows same status(value 0).

Is there a tip to make it work?

[kaspars.mednis]

Hi,

Zabbix external checks works only from Zabbix Server (or Proxy if configured)

You need to use agent userparameters or system.run agent keys to execute commands on remote hsots

The documentation:https://www.zabbix.com/documentation...types/external

External check is a check executed by Zabbix server by running a shell script or a binary. Zabbix server will look in the directory defined as the location for external scripts (parameter 'ExternalScripts' in Zabbix server configuration file) and execute the command.

[zabbixfk]

Try builtin service check , if you know what's the port number of postfix running

net.tcp.port[ip,port]

, i would check net.tcp.port[,25] in case of port 25 checking in the machine.

Other way is , system.run[command,<mode>], replace command with your command such as '

/etc/init.d/zabix_server status 2>/dev/null | grep -c running

, based on the return value create trigger.

If you still wanted to use custom script, create script, create a userparameter filed under zabbix_agentd.conf, then create as agent.

Thanks.

[sergioyy]

ActiveCheck with UserParameter

I'm create an UserParameter that works.
In this example, it is possible to check if postfix is running (returned [ + ] postfix by service command)

UserParameter=service_status, /usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;

When I stop postfix (sudo systemctl stop postfix), the trigger work well indicating service down.

But now, I facing a stranger behaviour. I configured this UserParameter on two linux ubuntu clients, monitored by one zabbix-server.

Only one is working correct. Comparing both zabbix-agent.conf, they are set as same way.

[zabbixfk]

Yes, comparing agnentd.conf should help.
Other thing you should do is, increase debug level 'DebugLevel=' in agentd.conf file, also make sure EnableRemoteCommands=1 & LogRemoteCommands=1, then checking log should help.
You can also simulate using zabbix_get.

Thanks

[sergioyy]

Different Ubuntu Versions

Thanks for your support !

I checked both zabbix-agent.conf and they are set as same way.
Versions of zabbix-agent are same:
zabbix_agentd (daemon) (Zabbix) 3.2.11
Revision 76339 27 December 2017, compilation time: Dec 27 2017 15:17:18

But linux versions are different.

[Zabbix-Server]
sudo lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial

sudo zabbix_server -V
zabbix_server (Zabbix) 3.2.8
Revision 72884 25 September 2017, compilation time: Sep 26 2017 17:51:56

Copyright (C) 2017 Zabbix SIA



[machine 1: not getting data from item]
$ sudo lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty

[machine 2: getting data from item]
$ sudo lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial

It could be a reason?

complementary information: zabbix-server, is monitoring both machines. I can see information about cpu load, memory, etc for each one. So zabbix-agents are working well.

[kaspars.mednis]

Hi,

try to run your command

/usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;

on both servers as Zabbix user, there may be permission issues. All userparameters are executed with Zabbix system user permissions

Regards,
Kaspars

[sergioyy]

Active Check permissions

Hi Kaspars, you were rigth. Running command as zabbix user, not working on machine 1. Now, what permissions should be checked?


[machine 1: executing command as zabbix user, no work]
sudo -u zabbix /usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;
0
[machine 1: executing command sudo, work]
sudo /usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;
1

[machine2: executing command as zabbix user, work]
sudo -u zabbix /usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;
1
[machine2: executing command sudo, work]
sudo /usr/sbin/service --status-all 2>/dev/null| grep -F "[ + ] postfix" | wc -l;
1