[hobbit] Cisco switches

[Buchan Milne]

On Wednesday 16 January 2008 20:50:02 Nikesh Maharaj wrote:
> I can ping the device by ip and by name. however, devmon still has a
> problem to query the device.

Well, devmon obviously does not ping. It does a number of SNMP gets to the 
device. When you run it with the --readbbhosts option, it runs in the 
foreground (thus, does no logging), and tries to retrieve the sysDescr value 
for each entry in bbhosts which has a DEVMON tag.

SNMP (v2) relies on a community string, which is effectively a password, 
to "authenticate" the SNMP client (manager). Devmon provides for generic 
community strings (set in the SNMPCIDS value in devmon.cfg). Thus, in most 
cases, the default devmon.cfg file is not going to work (you need to at least 
set SNMPCIDS, and probably BBHOSTS as well).

Devmon uses the sysDescr value to decide what type of device this is, and 
populates information to the "database file". The database file should be 
provided via the -d option to devmon (this is *not* the RDBMS referred to for 
the multinode setup).

To test whether devmon would be able to do this:

$ snmpwalk -v2c -c public xxx.xxx.xxx.xxx sysDescr

Replace public with the community string, and xxx.xxx.xxx.xxx with the IP. If 
you can't do this, fix the SNMP config on the device, or firewall access etc.

Setting devmon up is relatively trivial if you:
1)Know at least the minimum about snmp
2)You know the bare minimum of setting up software (read the documentation, 
read the config file and set the settings that are obviously incorrect for 
your environment, run the tool with --help etc.).

> There is no log file generated for devmon as yet. Any ideas ?

There's no use running devmon (without the --readbbhosts option) until you 
have actually managed to probe one device.

So, to get devmon running:
1)Edit the devmon.cfg file correcting values that are not valid in your 
environment
2)Run './devmon - --readbbhosts'
3)Start devmon with './devmon'

Add any relevant options (.e.g -vv, --debug, '-c /path/to/config', 
or '-d /path/to/hosts.db') described in the --help output.

You may want to use an init script for (3), a sample one is provided in the 
extras directory. You may want devmon to run as a dedicated user, in which 
case you should run (2) and (3) as this user, and ensure the directories 
devmon needs to write to are writable by this user. For these reasons, you 
may want to look at this patch (which I ship in the Mandriva package of 
devmon, which effectively works out-the-box): 
http://svn.mandriva.com/cgi-bin/viewvc.cgi/packages/cooker/devmon/current/SOURCES/devmon-correct-paths.patch?revision=41543&view=markup

I will probably merge some of my changes into devmon itself for the upcoming 
0.3.0 release (to make things a bit easier).

Now, if there is something which is not basic SNMP or Unix knowledge which is 
difficult about getting devmon running, please let me know so we can improve 
the documentation.

Regards,
Buchan