Howdy,
Well, it's been a good long time (almost a week) since I've posted anything but numbered lists of, hopefully, useful information. It's about time for a little scripting. So, just to maintain my sanity (if not your own - assuming you follow this blog a bit, for which I thank you), today I'm putting up a little Perl script I wrote to maintain connections to a simple Cyclades console server. It can be re-worked fairly easily to connect to multiple console servers of any kind.
Technically, this script could be used for any server which accepts connections over telnet (Which this script is set up to use, even though I'm pretty sure I fought the good fight arguing against it). For more information on why it's a bad idea to use telnet for anything you don't have to, check out our old posts on using tcpdump on Linux or snoop on Solaris to easily grab user passwords. It should also be noted that I wrote this for a non-primary employer (contract). The IRS can rest assured that they'll get their cut of my money at the end of the quarter, but I can't, of course, reveal the identity of the client at this point in time (and, for ethical reasons, I won't later, either, since, given the setup, it would be like setting up a turkey-shoot ;)
The script can be run simply, like most of the scripts we put out here, from the command line. It only requires that you supply a hostname and will spit out help information if you just run it with no arguments, like so:
host # ./dconsole.pl
Usage: ./dconsole.pl [-h|-l|hostname]
This Perl script is fairly limited for a reason, but it's very easy to expand upon and only requires minor adjustment to set it up to use SSH. Since, of course, SSH would require some sort of key-or-host-based authentication method set up before this script would work, be sure to do that before you just run this out-of-the-box. Believe it or not, we've got a post on distributing and setting up SSH keys network-wide on this site, as well ;)
Sometimes I feel like I'm beginning to write in a mobius strip ;)
Anyway, enjoy, and best wishes,
This work is licensed under a
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License#!/usr/bin/perl
#
# dconsole.pl - Connect to your console server or modify to connect to a whole bunch!
#
# 2008 - Mike Golvach - eggi@comcast.net
#
# Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
#
if ( $#ARGV == -1 || $#ARGV > 0 ) {
print "Usage: $0 [-h|-l|hostname]\n";
exit(1);
}
# This is a simple array to list out all hosts connected to the console server
@hosts = qw(host1 host2 host3);
if ( $ARGV[0] =~ /^-h$/ ) {
print "\n";
print "dconsole.pl - Mike Golvach - eggi\@comcast.net\n";
print "\n";
print "-h : This piddly screen.\n";
print "-l : List hosts available.\n";
print "hostname : host to connect to.\n";
print "\n";
exit;
} elsif ( $ARGV[0] =~ /^-l$/ ) {
print "\n";
print "@hosts";
print "\n";
exit;
}
$goodtogo = 0;
for $hostname (@hosts) {
if ( $ARGV[0] eq $hostname ) {
$goodtogo = 1;
}
}
if ( ! $goodtogo ) {
print "\n";
print "$ARGV[0]? Never heard of it.\n";
print "\n";
exit(1);
}
# This is a simple hash to associate connected hosts to their ports on the console server
%whatitis = qw(host1 2 host2 3 host3 4);
$conport = $whatitis{$ARGV[0]};
print "\n";
print "Opening $ARGV[0]...\n";
print "\n";
system("/usr/bin/telnet THECONSOLESERVER $conport");
exit;
, Mike
Wednesday, June 25, 2008
Simple Perl Script To Ease Console Server Use On Linux And Unix
Wednesday, March 26, 2008
Using Color In The Linux Or Unix Shell
Click the image above to see all the pretty colors bigger ;)
Hey There,
Today's we're going to go off on a tangent and take a look at color and the Linux and/or Unix console. I first noticed the use of color in the shell while using Linux a long long time ago, and it seemed really cool back then. Every now and again it bugs me, but I must admit that it does come in handy for a lot of things; editing code or simple file type identification are two great examples.
The script attached to this post was written mostly to illustrate the concept that you can see in the picture attached to this text. More to the point, I wrote it so that we could see the colors I'm writing about :) Admittedly, I used every possible combination of color and modification for completeness, which has the nasty side effect of making some of the output invisible (You can't see the black foreground on the black background unless reverse video or bolding are turned on), but that's the nature of the beast. You probably won't ever need or want to print black on black, unless you're writing a menuing system for someone you can't stand ;)
One thing to note is that the colors and modifications in this script are limited to the ECMA-compliant codes. Linux and the Bash shell, for example, have a lot more color options, but I wanted to keep this post as fairly balanced as possible. These codes should work on almost any Unix or Linux console and most SSH or Telnet shell clients today probably support them as well. Still, not everything will work everywhere. For instance, the blinking text code does not work on my PuTTY terminal, although it does work on my SecureCRT. Since I'm not paying for the color, I guess I can't complain ;)
Getting these colors to show on your terminal is actually fairly simple. First, you just need to know what all the codes stand for. Below is a quick listing. The 30's are foregrounds, the 40's are backgrounds and the remaining set are modifications (any and all of which can be combined, if you so choose):
# 30 black foreground
# 31 red foreground
# 32 green foreground
# 33 brown foreground
# 34 blue foreground
# 35 purple foreground
# 36 light blue foreground
# 37 gray foreground
#
# 40 black background
# 41 red background
# 42 green background
# 43 brown background
# 44 blue background
# 45 purple background
# 46 light blue background
# 47 white background
#
# 1 turn on bolding
# 22 turn off bolding
# 5 turn on blinking
# 25 turn off blinking
# 7 turn on reverse video
# 27 turn off reverse video
# 0 reset everything to default
Now, if you wanted to print a color to your screen, all you need to do is use the echo command (Note that -e tells echo to interpret the backslashed characters, so "\033[30m" doesn't show up literally). For instance, to print "HI" in red font, you could type:
host # echo -e "\033[31mHI"
The "m" character following the number code 31 (Indicating that you want to print in red) completes the instantiation of the color. Without it, your text would remain whatever color it already was. The incorrect echo statement may also have other bizarre side effects, like repositioning your cursor or resetting your terminal. The final "m" is very important :)
You can also combine different colors, as well as modifications, by using the semicolon. Below, the first line writes "HI" in light blue on a green background (Uggh) and the second does the same in BOLD :)
host # echo -e "\033[36;42mHI"
host # echo -e "\033[36;42;1mHI"
One thing to note is that all of these commands would leave your terminal stuck in whatever state you instructed on the command line. That is, if you used the color commands to type with a green background, your terminal's background would remain green after you typed the line. In order to return everything to normal, you can use the modification number "0" - This will reset your terminal to the default color settings. If you only want to print one line in red font, the line shown below would work better for you than the original (the first example, above)
host # echo -e "\033[31mHI\033[0m"
Note, also, that (for the color code commands) there can't be any spaces. "\033[31m" has to be one unit. The text you put in between this command and the closing "\033[0m" (should you elect to go back to the way things were ;) can have spaces anywhere, just like any other block of text.
Hope you have some fun with shell colors. Enjoy the script. If nothing else, it should serve as a good reminder of the syntax and a good indicator of the breadth of options ECMA compliant colors give you. Linux, as I mentioned, has even more variety, but using those specific codes can make your scripts less portable. Good or bad? You decide ;)
Cheers,
This work is licensed under a
Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License#!/bin/bash
# colors.sh - Print out all the different ECMA color-mod combos
#
# 2008 - Mike Golvach - eggi@comcast.net
#
# Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
#
declare -a color_array
declare -a alphabet_soup
color_array=( '30;40;1' '30;40;5' '30;40;7' '30;40;22' '30;40;25' '30;40;27' '30;40' '30;41;1' '30;41;5' '30;41;7' '30;41;22' '30;41;25' '30;41;27' '30;41' '30;42;1' '30;42;5' '30;42;7' '30;42;22' '30;42;25' '30;42;27' '30;42' '30;43;1' '30;43;5' '30;43;7' '30;43;22' '30;43;25' '30;43;27' '30;43' '30;44;1' '30;44;5' '30;44;7' '30;44;22' '30;44;25' '30;44;27' '30;44' '30;45;1' '30;45;5' '30;45;7' '30;45;22' '30;45;25' '30;45;27' '30;45' '30;46;1' '30;46;5' '30;46;7' '30;46;22' '30;46;25' '30;46;27' '30;46' '30;47;1' '30;47;5' '30;47;7' '30;47;22' '30;47;25' '30;47;27' '30;47' '30;1' '30;5' '30;7' '30;22' '30;25' '30;27' '30' '31;40;1' '31;40;5' '31;40;7' '31;40;22' '31;40;25' '31;40;27' '31;40' '31;41;1' '31;41;5' '31;41;7' '31;41;22' '31;41;25' '31;41;27' '31;41' '31;42;1' '31;42;5' '31;42;7' '31;42;22' '31;42;25' '31;42;27' '31;42' '31;43;1' '31;43;5' '31;43;7' '31;43;22' '31;43;25' '31;43;27' '31;43' '31;44;1' '31;44;5' '31;44;7' '31;44;22' '31;44;25' '31;44;27' '31;44' '31;45;1' '31;45;5' '31;45;7' '31;45;22' '31;45;25' '31;45;27' '31;45' '31;46;1' '31;46;5' '31;46;7' '31;46;22' '31;46;25' '31;46;27' '31;46' '31;47;1' '31;47;5' '31;47;7' '31;47;22' '31;47;25' '31;47;27' '31;47' '31;1' '31;5' '31;7' '31;22' '31;25' '31;27' '31' '32;40;1' '32;40;5' '32;40;7' '32;40;22' '32;40;25' '32;40;27' '32;40' '32;41;1' '32;41;5' '32;41;7' '32;41;22' '32;41;25' '32;41;27' '32;41' '32;42;1' '32;42;5' '32;42;7' '32;42;22' '32;42;25' '32;42;27' '32;42' '32;43;1' '32;43;5' '32;43;7' '32;43;22' '32;43;25' '32;43;27' '32;43' '32;44;1' '32;44;5' '32;44;7' '32;44;22' '32;44;25' '32;44;27' '32;44' '32;45;1' '32;45;5' '32;45;7' '32;45;22' '32;45;25' '32;45;27' '32;45' '32;46;1' '32;46;5' '32;46;7' '32;46;22' '32;46;25' '32;46;27' '32;46' '32;47;1' '32;47;5' '32;47;7' '32;47;22' '32;47;25' '32;47;27' '32;47' '32;1' '32;5' '32;7' '32;22' '32;25' '32;27' '32' '33;40;1' '33;40;5' '33;40;7' '33;40;22' '33;40;25' '33;40;27' '33;40' '33;41;1' '33;41;5' '33;41;7' '33;41;22' '33;41;25' '33;41;27' '33;41' '33;42;1' '33;42;5' '33;42;7' '33;42;22' '33;42;25' '33;42;27' '33;42' '33;43;1' '33;43;5' '33;43;7' '33;43;22' '33;43;25' '33;43;27' '33;43' '33;44;1' '33;44;5' '33;44;7' '33;44;22' '33;44;25' '33;44;27' '33;44' '33;45;1' '33;45;5' '33;45;7' '33;45;22' '33;45;25' '33;45;27' '33;45' '33;46;1' '33;46;5' '33;46;7' '33;46;22' '33;46;25' '33;46;27' '33;46' '33;47;1' '33;47;5' '33;47;7' '33;47;22' '33;47;25' '33;47;27' '33;47' '33;1' '33;5' '33;7' '33;22' '33;25' '33;27' '33' '34;40;1' '34;40;5' '34;40;7' '34;40;22' '34;40;25' '34;40;27' '34;40' '34;41;1' '34;41;5' '34;41;7' '34;41;22' '34;41;25' '34;41;27' '34;41' '34;42;1' '34;42;5' '34;42;7' '34;42;22' '34;42;25' '34;42;27' '34;42' '34;43;1' '34;43;5' '34;43;7' '34;43;22' '34;43;25' '34;43;27' '34;43' '34;44;1' '34;44;5' '34;44;7' '34;44;22' '34;44;25' '34;44;27' '34;44' '34;45;1' '34;45;5' '34;45;7' '34;45;22' '34;45;25' '34;45;27' '34;45' '34;46;1' '34;46;5' '34;46;7' '34;46;22' '34;46;25' '34;46;27' '34;46' '34;47;1' '34;47;5' '34;47;7' '34;47;22' '34;47;25' '34;47;27' '34;47' '34;1' '34;5' '34;7' '34;22' '34;25' '34;27' '34' '35;40;1' '35;40;5' '35;40;7' '35;40;22' '35;40;25' '35;40;27' '35;40' '35;41;1' '35;41;5' '35;41;7' '35;41;22' '35;41;25' '35;41;27' '35;41' '35;42;1' '35;42;5' '35;42;7' '35;42;22' '35;42;25' '35;42;27' '35;42' '35;43;1' '35;43;5' '35;43;7' '35;43;22' '35;43;25' '35;43;27' '35;43' '35;44;1' '35;44;5' '35;44;7' '35;44;22' '35;44;25' '35;44;27' '35;44' '35;45;1' '35;45;5' '35;45;7' '35;45;22' '35;45;25' '35;45;27' '35;45' '35;46;1' '35;46;5' '35;46;7' '35;46;22' '35;46;25' '35;46;27' '35;46' '35;47;1' '35;47;5' '35;47;7' '35;47;22' '35;47;25' '35;47;27' '35;47' '35;1' '35;5' '35;7' '35;22' '35;25' '35;27' '35' '36;40;1' '36;40;5' '36;40;7' '36;40;22' '36;40;25' '36;40;27' '36;40' '36;41;1' '36;41;5' '36;41;7' '36;41;22' '36;41;25' '36;41;27' '36;41' '36;42;1' '36;42;5' '36;42;7' '36;42;22' '36;42;25' '36;42;27' '36;42' '36;43;1' '36;43;5' '36;43;7' '36;43;22' '36;43;25' '36;43;27' '36;43' '36;44;1' '36;44;5' '36;44;7' '36;44;22' '36;44;25' '36;44;27' '36;44' '36;45;1' '36;45;5' '36;45;7' '36;45;22' '36;45;25' '36;45;27' '36;45' '36;46;1' '36;46;5' '36;46;7' '36;46;22' '36;46;25' '36;46;27' '36;46' '36;47;1' '36;47;5' '36;47;7' '36;47;22' '36;47;25' '36;47;27' '36;47' '36;1' '36;5' '36;7' '36;22' '36;25' '36;27' '36' '37;40;1' '37;40;5' '37;40;7' '37;40;22' '37;40;25' '37;40;27' '37;40' '37;41;1' '37;41;5' '37;41;7' '37;41;22' '37;41;25' '37;41;27' '37;41' '37;42;1' '37;42;5' '37;42;7' '37;42;22' '37;42;25' '37;42;27' '37;42' '37;43;1' '37;43;5' '37;43;7' '37;43;22' '37;43;25' '37;43;27' '37;43' '37;44;1' '37;44;5' '37;44;7' '37;44;22' '37;44;25' '37;44;27' '37;44' '37;45;1' '37;45;5' '37;45;7' '37;45;22' '37;45;25' '37;45;27' '37;45' '37;46;1' '37;46;5' '37;46;7' '37;46;22' '37;46;25' '37;46;27' '37;46' '37;47;1' '37;47;5' '37;47;7' '37;47;22' '37;47;25' '37;47;27' '37;47' '37;1' '37;5' '37;7' '37;22' '37;25' '37;27' '37' '40;1' '40;5' '40;7' '40;22' '40;25' '40;27' '40' '41;1' '41;5' '41;7' '41;22' '41;25' '41;27' '41' '42;1' '42;5' '42;7' '42;22' '42;25' '42;27' '42' '43;1' '43;5' '43;7' '43;22' '43;25' '43;27' '43' '44;1' '44;5' '44;7' '44;22' '44;25' '44;27' '44' '45;1' '45;5' '45;7' '45;22' '45;25' '45;27' '45' '46;1' '46;5' '46;7' '46;22' '46;25' '46;27' '46' '47;1' '47;5' '47;7' '47;22' '47;25' '47;27' '47' '1' '5' '7' '22' '25' '27' )
alphabet_soup=( ABC DEF GHI JKL MNO PQR STU VWX YYZ )
color_array_count=${#color_array[@]}
alphabet_soup_count=${#alphabet_soup[@]}
echo "Number of color code combinations in array = $color_array_count"
alpha_count=0
for ((x=0; x<$color_array_count; x++))
do
if [ $alpha_count -gt 9 ]
then
alpha_count=0
fi
echo -ne "\033[${color_array[${x}]}m${alphabet_soup[${alpha_count}]}\033[0m"
((alpha_count++))
done
echo
, Mike
linux unix internet technology
Saturday, December 15, 2007
Shutting Down Domains on Sun 6800/6900 Servers
Here's a little information that comes in handy every once in a while. As you get used to working with Sun's larger machines, the convenience of some of the more advanced features becomes almost trivial. It's common (at least for me) to forget, from time to time, that ServerA and ServerB actually reside on the same physical server (Server1, for example).
That's one thing you get reminded of very quickly when, say, ServerB has a hardware related problem and you need to fix it. When you're dealing with DataCenter class machines, you generally don't want to make a mistake and accidentally pull a card that belongs to ServerA in your attempts to fix ServerB. The headache-multiplication theory is taken for granted, not to mention that company's generally throw lots of money at humongous hardware so they can house systems of "greater importance" on them. ServerA and ServerB, almost literally, translate into lost-revenue when they go down. When you're stuck in this sort of situation, taking your time and doing things right (even if you need to take a gut-punch and "read the manual" ;) is always more important than trying to blast your way through it and hoping for the best.
Luckily, when you're dealing with the 6800/6900 server series from Sun, dealing with domains and working on a "single" machine on a multi-domain system is pretty simple as long as you take the necessary precautions (never be embarrased to type "help"). Also, just so I can start typing 6800 instead of 6800/6900 from now on; the only real difference between the two is the internal architecture. The 6800's are SCSI-based, while the 6900's are fiber. You'll note that this is the difference with almost all of Sun's server series that relate closely (the v480 and v490, or the v880 and v890 - All of them are just slightly different). The 900's and 90's were released because internal fiber disk is much faster than internal scsi-connected disk. To keep it simple ;)
As a for instance, let's say that ServerB is suffering terrible failures (even Sun can't readily explain them). A number of HBA's on the I/O boards have failed and there's a problem with one of the System Boards. Also, your root mirror disk is giving off errors left and right. This is a potentially horrible scenario for which no resolution will be given. We're just using it to make it so we can walk through the process of bringing ServerB down completely and replacing parts.
The first thing you'll want to do is to connect to the System Controller. This can be done any number of ways. Your site should have documentation related to how they've set it up. Generally it will be an SSH or Telnet connection to the SC. You can also set up direct connects for the Domain Consoles, but, even when we have them, I prefer to connect to the SC, as you can get to all of the Domain Consoles from there, as well as the "Platform Shell"! Assuming you've connected, you'll be at a terminal screen that looks something like this.System Controller 'Server1':
Type 0 for Platform Shell
Type 1 for domain A console
Type 2 for domain B console
Type 3 for domain C console
Type 4 for domain D console
Since this is also very specific to how your machine was set up, we'll go with the assumption that ServerA is on the "Domain A" console and ServerB is on the "Domain B" console. Since we want to work on ServerB, and leave ServerA up and running while we do, we'll type in the following (This may seem counter-intuitive at first, but the fact that I'm logging into the "Platform Shell" rather than the "Domain B" console can offer some enhanced control (when you get around to playing with it) and allows you to connect to any domain directly from it):
Input: 0
Platform Shell
Server1:SC>
Now we're at the SC prompt, at the Platform Shell level -- Remember, at almost any point along the way you can type "help" to get a list of all available commands. When you get a chance, do so, and you'll see what I mean about the enhanced flexibility that starting off at the Platform Shell offers. To continue, we'll connect directly to the "Domain B" console, which is just like logging into a regular machine serial console:Server1:SC> console b
Connected to Domain B
ServerB console login: root
Password: ******
And, just like on any other machine, we'll bring it down to an ok> prompt as if it weren't a part of a larger physical organism (Server1 - the big 6800)
ServerB# init 0
You'll get the regular system messages and whatever else gets spit to the screen when you normally shut down, and you're there. Now, we'll want to switch from the "Domain Console" to the "Domain Shell." We can do that like so:
{c} ok
<---------- Here type a literal [ctl]+] (the control key and the right bracket (]) simultaneously) - this will get you to a Telnet or SSH prompt - depending on your setup. Then, you'll send a "break" signal to make the switch from Console to Shell.
telnet> send break
Domain Shell for Domain B - ServerB
ServerB:B> setkeyswitch off <-- This command is the one that will "turn off" ServerB. Note that, if you've looked at the "help" output, you don't want to run "poweroff" - That could seriously ruin your day ;) The "poweroff" command is used for powering off the physical grids. Generally, on a two domain 6800, you'll only have one, so running "poweroff" might bring down both ServerB and ServerA. Sun only requires you to split your 6800 into 2 grids if you want to have 3 or 4 domains!
Powering boards off ...
ServerB:B>
Now your "virtual" server (ServerB) is off, and ServerA is still up and running as if nothing were going on. You're ready to begin replacing parts.
As a quick note; before you completely disconnect from the "Domain Shell," I always find it's good practice to run the following comand:ServerB:B> showboards
Slot Pwr Component Type State Status Domain
---- --- -------------- ----- ------ ------
/N0/SB1 Off CPU Board Assigned Not tested B
/N0/SB2 Off CPU Board Assigned Not tested B
/N0/SB3 Off CPU Board Assigned Not tested B
/N0/IB7 Off PCI I/O Board Assigned Not tested B
/N0/IB9 Off PCI I/O Board Assigned Not tested B
Write down the left-most column (Slot) and glance over the entries to make sure that they're all in the correct Domain (B, here) and that the "Pwr" (power) column lists them all as off. This will help make doubly sure you don't accidentally affect ServerA, as the CPU Board and I/O Board numbers are listed on the outsides of the devices and, if you've written this information down, you can refer to it and easily locate what part of the system you can safely work with.
And, of course (very quickly) for those of you who want to know how to get everything back up and running, just do the following (A very quick summary of commands and output here, as the concepts are all the same, but done in a logical reverse order; with the exception of the rarely needed "resume" command noted below)System Controller 'Server1':
Type 0 for "Platform Shell"
Type 1 for domain A console
Type 2 for domain B console
Type 3 for domain C console
Type 4 for domain D console
Input: 0
Platform Shell
Server1:SC>
Server1:SC> console b
Connected to Domain B
<---------- Here type a literal [ctl]+ ]
<--- Note that this command and the following are not usually necessary. Once you power on your system by doing the "setkeyswitch on," the 6800 will run through extensive system tests and boot the OS directly.telnet> send break
Domain Shell for Domain B - ServerB
ServerB:B> setkeyswitch on
Powering boards on ...
ServerB:B>resume
ok> boot
Hopefully the amount of time spent reading this will save you much much more in the future :)
Cheers,
, Mike
linux unix internet technology
