[rrd-users] help for a better perspective

[Alex van den Bogaerdt]

On Tue, Nov 13, 2007 at 12:29:29PM +0100, Pili Muñoz Gargallo wrote:
> hello, my name is Pili
> 
> I'm a student and i'm trying to understand how cacti works. I  know that it
> is the evolution of RDDtool and you need to have it installed  to made it
> works. I have been reading tutorials, to try  understanding but there's a
> thing i don't manage to find:
> Where i could find information about how configure the agents? i mean, i
> think i understand that  the NMS needs  a suite like cacti,  in the agent
> must be running Net-SNMP or similar, but i don't know how both interact...
> Where i would say the ip of the device i want to monitor? what happens it
> the net is already done and there's a switch that supports SNMP? how i could
> install Net- SNMP in an agent?
> May be these are no the kind of questions you are used to read, but i'm a
> student and i can't install things in the lab (i can't enter as root). The
> teacher told us to decide for an architecture, but it's very difficult to me
> to think in such an abstract way...
> 
> Thank you very much in advance, and i must apologize myself if my doubts
> have disturbed someone (or my schematic english)
> 
> best wishes

Tasks:

1: get data from somewhere
2: process and archive it
3: extract data (either as text or as graphic)
4: present the results to the user

SNMP can be used for step 1.
RRDtool is used for step 2 and 3.
Usually an HTTP server is used for step 4.

Cacti is one of the available GUIs to do these jobs.


Usually:
* You do not need to be root to do SNMP queries.
* You do not need to be root to use RRDtool.
* You do not need to be root to generate HTML content

1:
A device, such as a router or a computer, will run an SNMP program.
Another computer (it could be the same computer) can query this SNMP
server for data. The result is some numeric value.

2:
The numeric value is given to RRDtool. It does its job.

4:
A user requests a report, for instance by accessing an URL.
The webserver will need to fetch the data, which is step 3.


I think you should look elsewhere to learn about SNMP, HTTP, and
similar questions. 

HTH
-- 
Alex van den Bogaerdt
http://www.vandenbogaerdt.nl/rrdtool/