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My sysadmin toolbox

By Brian Jones on February 17, 2006 (8:00:00 AM)

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I administer servers and networking equipment in a small to mid-size heterogeneous (but 99.44% *nix) environment. I've worked on projects ranging from NIS-to-LDAP migration for authentication, to the deployment of a 164-CPU Beowulf cluster, to writing an extension to a large OO-PHP application. I'm a generalist, but my favorite areas are LDAP (and authentication in general), database design and administration, and automation (a broad category that includes writing tools and code to glue services together). Here are my favorite tools.

Minicom

Minicom allows me to use my laptop as a serial console. I can walk up to any server (x86, SPARC, whatever), plug into the serial port on the back, fire up minicom in an xterm window, and log in.

Telnet

Some readers are going to roast me for using Telnet instead of netcat, but in the cold, cruel real world in which I live, I do not always have a choice as to the installed software. If I'm consulting, I'm not going to tell a client that I need netcat to do what Telnet (which is already installed) can do just fine. If you want to test connectivity to your mail server, you don't have to have a fat mail client (or a mail account for that matter). Just telnet to port 25 of the mail server.

SSH

I might use SSH more than any other tool except for the shell, which I use to launch it, and the terminal, which I open to get to the shell. What I like best about SSH is that, using shared keys, I can mostly do away with sending any kind of password over the wire. Also, there are services in my environment that require the use of a GUI interface -- I'm not learning every Veritas command line tool, thanks -- and with SSH, I can tunnel an X session back to my workstation.

X.org

I don't run X on a server unless it's a requirement of a service or application it provides. However, I do almost all of my administration tasks from my workstation, which runs dual screens and X.

People who say you can get the same functionality from using screen and VTsplit and the like have probably never spent enough time in an X environment to know the beauty of dual screens, where you can quite easily keep track of several different service or host monitors, email, my admin group's Jabber chat room, several documentation sources, Slashdot, Gmail, and lots of extra niceties like the weather and package update notifications via alert applets in my taskbar.

I don't care what window environment I'm in. I use fluxbox, KDE, GNOME, and Xfce depending on the machine and my mood.

ClusterIt

ClusterIt is actually a suite of about a dozen or so tools that come packaged together. They're meant for use in Beowulf-type environments, but oddly enough, I don't use this suite on the cluster I maintain. I use the tools on collections of machines that are identically configured, such as our Linux development machines, a 30-node teaching lab running Fedora, or a collection of Solaris service machines.

Want to know which machines a particular user is logged in on? Try running the ClusterIt utility dsh "w|grep username". This doesn't even begin to describe the power this suite of tools gives you.

jEdit

If I'm doing anything on a remote host that requires an editor, I use vi or Vim. This is probably 85% of my file editing. However, if I'm writing code on my local workstation or on my laptop for deployment later elsewhere, I use jEdit these days. It's a nice, unassuming, unpretentious editor that lets me do just about whatever I want. It gets code blocks out of my way when I'm not reading them, it has a keyboard shortcut config tool that lets me emulate Vim moves I can't live without, it supports more languages than I'll ever use, and it lets me alter every language element in terms of how it's colored or highlighted.

jEdit makes managing multiple open files easy, and there's probably a plugin for anything I haven't thought of using it for yet. If you've been using Bluefish or Quanta, you might find that jEdit fits your brain a little better.

Xmeter

I've written about xmeter before, and it's still a tool I rely on every day. It's a graphical utility used to monitor statistics collected by remote hosts' rstatd daemons. I use it to do simple load monitoring of just about all of the hosts in my environment. You can set xmeter thresholds, so if, say, the load on any server goes through the roof, the monitoring graph changes color from green to bright red.

Xmeter is, to my knowledge, not maintained, but you can grab a zip file of the source and man page from my site.

man

This is one of those tools that you'll never stop using. It's not useful only if you don't know something; often it's useful to give yourself a sanity check. If I find myself in a machine room, and it's after midnight, and I have to run any command starting with "ch" on any system, I check its man page just to make sure.

Forget the -h on a call to chown on a Solaris system using non-GNU tools, and you could inadvertently change the ownership of your entire directory hierarchy. Who ever remembers that you need a ; at the end of the argument to the -exec flag of the find command?

The man command is the first thing I consult when I get a goofy error from a command, but it's also useful for figuring out what a particular function call does or the syntax of various configuration files.

Ping

Ping is another tool that is installed by default on just about every machine I've ever logged into. If I'm logged into a Solaris 7 box, and I need to see if another machine is up and running and connected to the network, I'm running the ping command, because that's all that is likely to be there. Sure, I'd rather use something like hping, which supports far more than just simple ICMP, or even fping, which at least makes pinging a collection of hosts a little more friendly, but I don't often find these tools installed at client sites, and I don't even have them installed ubiquitously in my own environment.

Network grep (ngrep)

I don't trust apps that say they're using encryption -- I test. If I'm at a site where I'm responsible for the security of an application, and ngrep is not installed, I will request that it be installed. If they say no, then I request that I be able to mount a CD or USB device with a binary on it I can use.

Ngrep is "network grep". It'll capture packets that contain data matching a given pattern. If I want to test for encryption, I launch ngrep on the server with a command like ngrep badpass port 389. This will look for any packets whose data contains the string badpass.

If ngrep finds one, then clearly the data was not encrypted, and something is going wrong. You can also use ngrep for basic tcpdump-like functionality, and can tell it to inspect files instead of traffic from a device.

Let us know about your most valuable utilities (there need not be 10 of them), and if we publish your work, we'll pay you $100.

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Hiding code and customizing colors in Vim

Posted by: Anonymous Coward on February 17, 2006 08:41 PM

If you like using Vim, but have wanted to do the things you described that you like in JEdit (hiding blocks of code and tweaking your colors), you can do as much in Vim if you want. To hide blocks of code, you use what Vim calls "folding" You can either use the "<tt>zf{motion} </tt>" command to fold a range, or you can highlight a range and then type "<tt>zf</tt>" to fold the text to a single line. For more info, see Vim's online help at "<tt>:help folding</tt>"




For altering your colors, you can either choose an existing color-scheme, take an existing one and modify it, or even build your own from scratch. This is described in "<tt>:help<nobr> <wbr></nobr>:syn-default-override</tt>".




One of the things I love about Vim is that wherever you go, there's vim. I can use it on Win32, Linux, *BSD, MacOSX, etc. If you like Vim and just didn't know about these features, hopefully they'll serve you well.


-gumnos



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sysadmin toolbox

Posted by: Anonymous Coward on February 17, 2006 11:15 PM
Great review of your Toolbox, You have a pretty impressive job and some great tools to help you along. I enjoyed the read. Thank you!

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telnet has its use

Posted by: Anonymous Coward on February 18, 2006 10:10 PM
Honestly, what's wrong using telnet for testing tcp services? They roast you when people use to login as administrator over insecure network spreading his precious password around when you can hide it easily.

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