Multiple Zabbix 3.0 LTS web front end - confusing problem, conflicting Zabbix status

[ITOMDave]

Hi all,
I have installed a single Zabbix 3.0 LTS server on Azure. I have enabled the web front end on the Zabbix server itself and I have also configured a 2nd VM with only the front end.

Following some interesting tussles with SELinux and Azure network security I have now got both front end's working. BUT........

When I access the Zabix front end via the Zabbix Server itself, the initial dashboard tells me that the Zabbix server is running. However, when I access the Zabbix server via the 2nd front end VM the initial dashboard says that the Zabbix server is NOT running. Further, even though the 2nd VM says that the Zabbix server is NOT running I am able to successfully create hosts (just a simple task) via the 2nd front end.

In summary, the Zabbix status dashboard is saying a different thing when accessed from different web front ends.

I hope this is clear

Has anyone else had this issue or offer me some advice on how to address it.
All advice is gratefully received.

Regards,

Dave

[ingus.vilnis]

Hi Dave,

Welcome to Zabbix forums!

Each Zabbix front end is checking if the server is running by verifying if the server is listening on port 10051. The address and port of the Zabbix back end server is set when doing the last step of front end server's web setup or in a configuration file.

Most likely you have a SELinux or a network thing. From the command line of the 2nd front end server see if you can do "telnet <server IP or DNS> 10051". You got to have that working first. If the connection is open then firewall seems to be ok. After that check what else is SELinux blocking and if possible for a quick test see if it works with SELinux set to permissive. If no such option then look in the audit log for more denied records on Zabbix.

[ITOMDave]

Hi Ingus,
Many thanks for the pointers it helped guide my investigations a lot. I put SELinux into permissive mode and that didn't seem to make a difference and installed the setroubleshoot package to help out as well. None of which helped.

Of course, the thing that did help is reverting back to basics

traceroute, telnet etc etc were all failing as well so it was definitely something network related - obvious start point is routing.

More obvious start point though was to check on Azure networking.

What I'd done was to use the public IP address of the Zabbix server as the Zabbix host. I changed the address to be the private IP address and hey presto its now working as expected.

Summary

• If you want to host multiple front ends on Azure, use the private IP address of the Zabbix server as the $ZBX_SERVER parameter in /etc/zabbix/web/zabbix.conf.php on the front end.

Thanks Ingus, good pointers gave me a decent start point.

Dave

[ingus.vilnis]

Hi Dave,

Glad you got this sorted. Specifics of Azure came into play.
Now have a great time monitoring!

BR
Ingus

[DmitryL]

Using private IPs is indeed a good/better idea to do in Azure or in any other cloud platform.
But usage of Public IPs definitely was not a root cause of an issue. Possibly you forgot to add NSG for some NICs