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So You Want To Be A Linux System Administrator?

Published on Nov. 1, 2010 at midnight by XC

I was digging through Server Fault today looking for some thoughts on CARP (think HSRP, just free) and came across an honest and interesting question. The author wanted to know what skills and experience would make him more desirable in the world of UNIX like operating systems. I began to answer his question and found myself writing an entire anthology as an answer, so I’m bringing it to my blog instead. A bit of background for those who don’t know me, I’m someone who hires programmers and system administrators. My business card says CTO and I’m not ‘part owner of a start-up’ (anyone who doesn’t get that joke wouldn’t appreciate it anyway), so I consider myself to be somewhat authoritative on the topic.

The first thing you need to do is stop thinking and saying the word ‘Linux’. I’m not going off on an idealistic tangent, I’m advising you to realize that you are working with a UNIX like operating system. Linux is an awesome kernel, your experience is rooted (no pun intended) mostly in user space. For now, get the word out of your head completely. Go meditate if you think it will help, I’ll wait. When you start thinking “UNIX that doesn’t suck”, continue reading. In a nutshell, if I’m going to hire you, it’s because I know you can figure out a solution to practically any problem that you might face.

Category: GNU
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Why I Don’T Spend Money On It Certifications

Published on Oct. 30, 2007 at midnight by XC

Some reports that were recently published talked about GNU/Linux professionals without certifications making more money with less turn over than professionals with certifications.

I have never felt the need to waste my money on Linux certifications, for serveral reasons:

I actively contribute to many free / open source software projects as well as GNU/Linux distributions. My code and contributions on third party (authoritative) web sites carry much more weight than any certification.
I’m often in charge of interviewing and hiring people as programmers and system administrators. I don’t look at the certifications, many of them aren’t worth the paper that they are printed on.
I’m far from alone in my decision to give Linux certifications any serious weight when considering a new hire.

If you were interviewed by me for a position as a system administrator, the interview would be rather quiet. I would sit you down in front of a small network of VPS servers and say “Set this, and this, and this up, then install this and this. After that, install and configure this with this”
Knowing that my list would take most ‘good’ admins slightly under an hour to complete, I don’t inform you that the test is being timed. 2/3 of the things to install and configure would be found in the OS packaging (yum/apt-get able). The rest of the stuff would need to be built from source. Whoops, I must have forgotten to install gcc and needed libs when I setup the small sandbox network.

Category: GNU
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Bbc Blunders : “We’Re Not Gonna Take It.”

Published on Oct. 25, 2007 at midnight by XC

The BBC asked the head of the Free Software Foundation, Richard Stallman to write an article for their “Tech Lab” column, a smorgasboard of insights and brainstorming written by various technology industry leaders.

Stallman wrote an article, the BBC refused to publish it. Stallman insisted that the article contain a copying permission notice, allowing anyone to copy the text (verbatim) directly from the BBC web site. As policy, the BBC does not permit copies of materials that they publish, even if they are not the authors.

Apparently, whoever contacted Richard Stallman knew very little about him. You can not find one line of code or text that he’s produced since the mid 1970′s that is not free to copy (provided that you preserve his copyright notice). What did they expect from the guy who invented “Copyleft” ?
Sometimes, you just have to shake your head and chuckle. The article that is not going to be published on the BBC web site can be found here, which reacts to things previously published in the BBC Tech Lab column.

There’s a bit of buzz flying around the blog ecosystem regarding this rather funny incident. It was not the content of Richard’s article (even though it did criticize the BBC to a degree) that prevented publication, it was simply the fact that Richard wanted permission to copy to remain in the article. I’m not going to comment on the article, I respect Richard Stallman, I just don’t share his views on many topics.

Asking RMS to impose restrictions on creative works is like asking a fire hydrant to run the fifty yard dash – not likely to happen. You would think that BBC producers would spend a bit of time researching those who they ask to contribute, yes?

Category: GNU

Ubuntu Feisty Xen Image Available

Published on Oct. 18, 2007 at midnight by XC

I’ve been promising several people for the past couple of months that I would make a Feisty Xen guest template when I got “around to it”.

Well, I got around to it and the template is available for download. You’ll find the md5′s in the directory listing.

The template was bootstrapped (32 bit) using debootstrap, I then made the following modifications:

hwclock and console stuff disabled in init.d
Installed SSH and friends
Removed sound/usb stuff
Installed libc6-xen (init never complained, so I did not rebuild it)
Fixed a few things so the boot screen isn’t so mangled over the Xen serial redirect
Setup a generic fstab (sda1 is / , sdb1 is swap)
Configured aptitude to pull from Feisty main, universe and multiverse including the feisty-updates and feisty-security repositories.
Several other very minor things that I can’t remember off the top of my head.

To use the template, you need only a working installation of Xen.
Get going by doing by un-archiving the template, creating a small swap virtual block device (file or LV backed, whatever), create a configuration file that looks something like this:

name = 'feisty'
memory = 128
kernel = '/boot/vmlinuz-2.6.18-xen'
root = '/dev/sda1 ro'
disk = ['phy:/guests/feisty/rootfs,sda1,w',
'phy:/guests/feisty/swap,sdb1,w' ]
vif = ['bridge=br0, mac=00:00:6d:8e:4c:31, vifname=feisty.0']
You’ll want to change the disk [] array to indicate your setup, and the type of block device you created (a loop device would of course be file:/). A swap image is included to get you started, as well as a sample Xen configuration file.

Typically, I use LVM for virtual block devices. File backed VBDs are rather slow
Copy over the modules of whatever kernel you are using (most will be 2.6.18) to the /lib/modules/ directory of the VPS template, boot via xm create feisty.cfg then xm console your way in.

By default, eth0 wakes up wanting DHCP. Change that if you like in /etc/network/interfaces. The default root password is simply password and you can find a list of packages installed in /root (installed.packages iirc)

It might be a good idea to do an apt-get update and apt-get upgrade, depending on when you read this and snag the template. Any problems using these should be reported to tinkertim@gmail.com.

Happy Xenning
Update: 11/28/07

This image has been cleaned up and sent to jailtime.org as a contribution. Comments are welcome, however please post any serious issues with this image on the jailtime wiki.

Update: 9/17/08

I am through with Ubuntu. These images are no longer supported, nor will I be contributing more in the future. However, I will be making more for Debian as it evolves.

Category: GNU

Gnupanel Soon Open To Developers

Published on Oct. 15, 2007 at midnight by XC

I’ve received notice from Jorge and Ricardo, the lead developers of GNUPanel that very soon I’ll have a new semi-properized set of installation scripts. Once I get them, Mercurial repositories will be created. I’m planning the following:


Branches from core developers
Main (stable) public branch
Dev (unstable) public branch


Patch queue for stable (cherry picked)
Patch queue for dev (feeds stable)


Themes & modules


Everything else that warrants its own branch

This should allow the community to pull in (basically) anything that they want. You might want a few patches from stable, and one or two from dev. You might want to run stable but pull in some new feature from dev, and keep that new feature up to date. With this setup, pretty much anything (should be) possible.

Category: GNU
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My Backup Enchilada

Published on Oct. 14, 2007 at midnight by XC

In all honesty, this is just a recipe for my enchilada, I’m still in the prep and planning stage.

My goal: Make a really efficient idiot-proof backup program that (could) use the the features of an ext3cow file system if one happened to be present.

I don’t spare a penny when it comes to computers that I lease to others, all SAS or SCSI drives, nice RAID cards (some with SODIMM caching), plenty of RAM (4GB minimum ECC), all the trimmings.

My desktop computer is a puny little p4 HT 3.0 with dual slow IDE drives, 1 GB of ram. My forky ad-hoc backup scripts cause this particular machine to slow to a crawl for two hours a day. I need something better, I bet a lot of people do.
I’ve been working with using inotify() to alert me of file activity in hostile places like /tmp on some of my production machines. I see no reason why I can’t use inotify watches to do smarter incremental backups.

My ideal system has :

Super easy configuration with an optional Python GTK front end for desktop users (could do this with php, too, easily).
bz2/gzip libs built in so that there is no need to fork tar / gzip (allowing the backup program to better watch and control its resource usage).
Crypto built in and made simple.
Built in hooks for the extended ext3cow ioctl API (for snapshots and epoch retrieval).
Multi-user friendly, every user has a backup configuration that they manage in their home/ directory.
Simple client to do restores, with the ability to create rescue disks.

Category: GNU
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