snmpset To the Rescue!

A big, ugly, hairy, monotonous task recently fell in my lap at work. I had to update a couple configuration settings in approximately 900 menu-driven network devices. Each device had an independent authentication method with four or five possible username/password combos, and different menu options depending on firmware version. Completing one box would take about 2-3 minutes. Multiply that by 900 and you're looking at a solid week of nothing but menu navigation and data entry.

This ranked very high on my "List-of-things-that-make-me-want-to-stab-my-eyes-out".

The disparity of versions and lack of a single configuration standard rendered my usual methods of scripting useless. A dark little rain cloud settled over my cube.

Then my boss made the comment, "These things have SNMP, right?"

I heard, "These things have SNMP write?"

I immediately started researching and sure enough, I could use the "snmpset" command to script the updates for me!

WIN!

Here is a copy of the 'bulk_snmpset.sh' script that I used to do the updates:

#!/bin/bash

while read HOST RWSTR; do
snmpset -v 2c -c $RWSTR $HOST <snmp_oid_here> a "192.168.100.100"
done < $1

I fed this script a flat text file (hosts_to_update.txt) with the 900 host names and their respective SNMP read/write string that looked like this:

10.10.10.1 SNMPrwSTRING1
10.10.10.2 SNMPrwSTRING2
10.10.10.3 snmpRWstring3
...

Actually making it worked, looked like this:

me@ubuntu:~/scripts $./bulk_snmpset.sh hosts_to_update.txt

All that remained was to capture the ones that failed and either adjust the script accordingly or take care of them manually

Clever Solution to IE Caching Ajax

I ran into a problem today where IE was caching my AJAX responses so updates wouldn't be displayed and after a bit of hand-wringing over some of the suggested solutions (swapping GETs for POSTs, re-writing the page inPHP, etc), I found a clever little solution - add a time stamp to the GET string.

var t = new Date().getTime();
...
ajaxUrl += '&timestamp='+t;
...

Adding this time stamp will differentiate the URL and thereby force IE to reload the Ajax content.

Win.

EeePC 701 Conky & World Daylight Wallpaper

UPDATE!!! 17 NOV 2010 - Recently, a change on the static.die.net site wget not downloading the actual world map, but just a black picture instead. It turns out that this only affected wget so to work around this, I've added the option of '-U "pwnd"' to the wget line to send a user-agent string and now it works again!

I read an article on Lifehacker yesterday about how you can set a day/night rotating map as your desktop background. At first I was like, "Hey, this is awesome!" Then I remembered my conky setup and realized that it wouldn't work as it requires a static color background behind the text in order to be visible and the world map is being constantly downloaded and over-writing the image so I was all, "Dangit, that would have been cool =(". Then I got an idea! I could use ImageMagick to glue the static conky background on to the world map so I high-fived myself and went, "pwnd!"

</valley_girl>

Here's what you'll get when you're done:

As the day progresses (and provided that you're connected to the internet), the day/night image will be updated every hour. Additionally, this script will draw a transparent gray band on the newly downloaded world map that you can overlay with your .conkyrc config.

Here's my setup:

.conkyrc

# This is my conky config, you'll need the
# Envy Code R VS font if you want to match my setup
# otherwise any monospaced font will do
alignment top_middle
border_width 0
default_color AAAAAA #white
draw_outline no
draw_shades no
use_xft yes
gap_x 0
gap_y 250
own_window yes
own_window_title conky
own_window_transparent yes
own_window_hints undecorated, sticky, below, skip_pager, skip_taskbar
double_buffer yes
update_interval 1.0
use_spacer none
short_units yes
draw_graph_borders no
default_outline_color black
use_spacer left
default_bar_size 250 5

TEXT
${font Envy Code R VS:size=40}${alignc}${time %R}${font Envy Code R VS:size=10}
${alignc}${time %A, %B %e}${font Envy Code R VS:size=8}
${voffset -50}${fs_bar 5, 250 /} sda${alignr}bat ${battery_bar}
${cpubar 5, 250} cpu${alignr}wlan ${wireless_link_bar 5, 250 wlan0}
${membar 5, 250} ram${alignr}${wireless_essid wlan0} ${addr wlan0} - ${upspeed wlan0} / ${downspeed wlan0}
${tab 775,0}${color black}.

animated_background.sh

#!/bin/bash
# This will download the day/night map and apply the gray band to the top of it
# You'll need to 'sudo apt-get install imagemagick' and
# 'chmod +x ./animated_background.sh' for this script to work
wget -r -U "pwnd" -O 800.jpg http://static.die.net/earth/mercator/800.jpg
convert -size 800x70 xc:'#40404090' ./grey_stripe.png
convert -resize 800x480! ./800.jpg ./800.jpg
composite -geometry -0+255 ./grey_stripe.png 800.jpg ~/Pictures/world.png
rm ./grey_stripe.png ./800.jpg

Then you'll need to set the script to run hourly using either crontab or gnome-schedule as shown in the Lifehacker link.

Cheers!