How Zabbix agent Works ?

[themons]

1°I need to know how zabbix agent works
- which protocol does Zabbix agent use to communicate with the server (SNMP,... ?)
- where Zabbix agent found information about the host (/proc/...,Zabbix code ?)

i must build a little "flow chart" to explain zabbix communications

2° i must also compar differences between Zabbix_agent and built-in snmp agent of windows and linux(snmpd)

3° what is the differences between Zabbix_agent and zabbix_agentd

4° have you ever have problems of security with the Zabbix_agent

Thanks for you help.

[themons]

Linux-specific note. ZABBIX agent must have read-onle access to filesystem /proc. Kernel patches from www.grsecurity.org limit access rights of non-privileged users.

put in little char of the zabbix doc, Zabbix agent certainly take information in the /proc but i am not sure

[cooper]

1°I need to know how zabbix agent works
- which protocol does Zabbix agent use to communicate with the server (SNMP,... ?)
- where Zabbix agent found information about the host (/proc/...,Zabbix code ?)

I cant explain the protocol as I havent poured through the code, but i can give you an overview of the communication process:
zabbix_sender - sends data to zabbix_server
zabbix_agent(d) - listens on the monitored host
zabbix_server:
- queries agent(d) and puts data into database
- listens for data from zabbix_sender and puts into database.
- queries snmp hosts and puts data into database

2° i must also compar differences between Zabbix_agent and built-in snmp agent of windows and linux(snmpd)

Well, windows snmp support is awful. You can get very little out of the stock snmp. You can extend with the stuff from http://www.wtcs.org/snmp4tpc/ but you have to buy the enhanced version. Plus on windows with zabbix you can query any perfmon counter.

On linux snmpd is much better. But having a native agent can provide for better data.

Also, on either platform, zabbix is very extensible.

3° what is the differences between Zabbix_agent and zabbix_agentd

agentd will start, daemonize and listen in the background for connections.
agent must have connection handed to if from (x)inetd.
agentd has a few items that agent does not support. Its generally easier to use than agent.

4° have you ever have problems of security with the Zabbix_agent

I use agentd and have had no problems so far.


HTH

cooper

[themons]

i have not realy understand agent support more "item" than agentd?

if you are interesse zabbix use simple TCP SYN/SEQ/ACK request .... ( i use Ethereal )

[cooper]

i have not realy understand agent support more "item" than agentd?

From the manual (http://www.zabbix.com/manual_config_items.php, bottom of the page):

"Parameters netload*, disk_read* and disk_write* are supported by zabbix_agentd only. Inetd version of the agent does not support them."

Agentd, supports a few more items than agent.

cooper

[themons]

disk_read never work i don't understand why because other function work.
did i need an another package to make this features worke or is it an other probleme...

I work with a Debian Sarge 2.6.8 on a laptop

Durring the use of Etherlink I see lot of "Cheksum error" in Zabbix communication is it normal or not ???

[cooper]

can you post zabbix_agentd.log and zabbix_server.log?

[themons]

zabbix_agents.log

005169:20050302:143735 zabbix_agentd started
005170:20050302:143735 zabbix_agentd 5170 started
005171:20050302:143735 zabbix_agentd 5171 started
005173:20050302:143735 zabbix_agentd 5173 started
005174:20050302:143735 zabbix_agentd 5174 started
005172:20050302:143735 zabbix_agentd 5172 started

Zabbix_server.log is certanly on the zabbix server and i have no access to it.
--------------------------------------------
If Somebody is interesse i read the source code and i understand that Zabbix_agentd search informations in the /proc/ files

[cooper]

We really need to see the server log. It will show where the disk_read items are queried, and what values are being returned. Without that, I dont have any other ideas.

[themons]

i read the server log and there is nothing about the disk.

the function disk read status is mark not supported. Did i need a program on my computer (such as hdparm)

[cooper]

the function disk read status is mark not supported. Did i need a program on my computer (such as hdparm)

I dont think so. Alexei, any thoughts?

cooper