Delving into OpenBSD 4.5 - One humble Linux User's Perspective

blowfish-notext_openbsd.jpg

Recently, I decided to rebuild my Asterisk box. The catalyst in this decision was my distaste for the Trixbox distribution. More specifically, the very difficult time I had updating the software (ie kernel, modules, libraries, etc). I'll probably never understand the rationale of these YUM repositories. Case in point - I was running CentOS 5.2 and needed to rebuild the zaptel drivers. Running a simple 'yum -check-update' would spew all types of repos errors. So, I would then have to scour the net to find suitable repos for hardware configuration. These repos would seem to change on a regular basis. I simply found updating RPM based distros a royal PITA. Perhaps I became spoiled with the simplistic tar ball or .deb approaches.

I also found that Asterisk 1.2.4 was getting rather long in the tooth. Though, I had heard that updating to 1.4.x would require substantial tear up of my initial configuration. Some folks even suggested that I would lose some level of customization too. Perhaps the last straw, was the mysterious disappearance of my dialtone. I spent a couple days troubleshooting the concern. A couple of calls to Broadvoice tech support only added to my frustration. Of course the problem was on my end and not their end.

So, I figured I'd take the plunge into a GUI less Asterisk install. I fully expected to stub my knuckles a bit, but I knew that it would be far more educational and extremely gratifying.

Now the question was which Linux distro would I use? Obviously, I needed a very lean install, as my server only had a 10GB hard disk. Modest amount of 512MB RAM. I was leaning towards Slackware, because Dann Washko rebuilt TLLTS Asterisk box using Slackware v12.0. Then I saw slackmini project, which was based on Slackware v13.0 rc1 and was bundled with Asterisk 1.6.1. While both may have been great choices, I wasn't sure that Slack was small enough for my needs. My beloved distro has grown to DVD size (most Linux distros have grown in size), fine for a robust desktop, but not for a meager PBX server install. So you ask, "Why didn't I use Slack 7.1 or Slack 8.0"? The earlier Slackware distros (pre v 9.0) were small enough to fit on a CD.
Well, I desperately wanted the 2.6.x kernel. So both of those older yet much smaller slack installs were ruled out.

Enter OpenBSD! A very mature and secure OS, which I had been longing to try for quite sometime. I suppose that I never had the need to scratch this particular itch.
Well, the proverbial teaching moment had arrived albeit by necessity. So, I decided to take the plunge.

First observations

  • Disk Partitioniong
  • pkg_add & Ports
  • Mounting ext3 filesystems

The disk partitioning schema is quite different than classical Linux /dev/hd* or /dev/sd*
A quick look at /etc/fstab demonstrates this point..
$ cat /etc/fstab
/dev/wd0a / ffs rw 1 1

I'm not sure how the disk partitioning labeling conventions were derived, but I would imagine that it is probably a holdover from earlier Unix paradigms. It also took me awhile to figure out how to modify and write out the changes to the disk during my partitioning exercise. I suppose that I'd become dependent on the familiar fdisk partitioning tool. After I RTFM I figured it out. Not too tough, just different.

After installation, I was delighted to learn that the entire base install weighed in at a meager 480mb. Of course that is prior adding ports and other various. Still that is pretty impressive.

IMHO, the BSD package management system is perhaps the most powerful aspect of the OS.
If you have ever spent time fooling around with RPM dependency hell, you can definitely appreciate a robust package management tool. I was amped to take ports for a spin.
Before I got into ports I had to setup simple pkg_add environment. Basically, the pkg_add utility circumvents the need to compile / build software. It just seems to grab all of the required library dependencies from the chosen FTP server dictated by the 'PKG_PATH' variable.
It is very important to read the docs found here -> FAQ They do a very good job explaining some of the pitfalls people run into when trying to configure an OpenBSD system. One nagging problem that I created was mixing -current with -stable packages. If you do this evil, pkg_add utility will throw all types of dependency checking errors. I was chastised in #openbsd (IRC) for committing this mortal sin.
Really a bummer. It would seem that you cannot backout these sorts of changes. Once you decide to follow the -current tree you cannot decide to run -stable or vice versa.
Not sure how I created this problem, as I was simply attempting to install subversion so that I could get Zaptel/Dahdi drivers for openbsd. It seems that Asterisk-BSD developers only offer the Zaptel/Dahdi drivers from a subversion tree. Without the ztdummy drivers teleconferencing won't work. I'm still untangling the mess that I created. Oh well, I digress..

I suppose pkg_add utility could be compared with 'apt-get' utility found on Debian based systems. Last word on pkg_add. Since ftp is the chosen protocol, you simply gain access to the repository via anonymous login. I'm not sure how package content verification works. I could not find any evidence of md5sum at work anywhere. I suppose I'll need to read a bit more.

One other bit of confusion that I ran into was that I expected the openbsd ISO to include the ports software that can be found here -> /usr/src. Wrong answer. The ISO was essentially a bare bones network install tool. It simply took a bit of reading to figure out that you run CVS to take a snapshot of the ports repository of your choice. Once you take the appropriate snapshot of the ports tree you have chosen. The source code and ancillary libraries are grabbed by via CVS and /usr/src is created.

Something similar worked for me..

# cd [portsdir]/; cvs -d anoncvs@server.openbsd.org:/cvs update -Pd -rOPENBSD_4_5

This process could take a while if you're running on a slow connection. Once you begin to use the ports system, you'll immediately discover that running 'make' in the appropriate ports directory for the software of choice becomes quite trivial. Very cool indeed. Some people might compare BSD ports to Slackbuilds or Gentoo Portage experience. Once again this will only work if you haven't munged your source tree ( ie mixing -current with -stable).

I suppose the one deal breaker and actually quite befuddling discovery was the lack of out-of-the-box support for ext3 filesystem. I spent a considerable amount of time backing up the config files of my erstwhile Trixbox install to an external USB hard disk. My assumption was that I'd simply be able to plug it into my new BSD box and run 'mount -t ext3 /dev/sda2 /mnt' To my disappointment this failed miserably. Apparently BSD only supports read / write abilities for ext2 filesystem. Egads, I'm very surprised. In the Linux world this would be synonymous to a world without samba. That is not being able to transfer files from M$ windows computers.

Yes, I'm being a bit dramatic here ;-) Anyway, I failed in my first attempt to mount the disk.
It is important to note that you can actually mount ext3fs within OpenBSD. In fact there are ext2fs (e2progs) tools which allow you to manipulate the ext2fs. After all ext3fs is actually ext2fs with the journaling feature added. I'm not so sure that you can mount the native BSD (FFS) filesystem within Linux. I'll have to research that answer.

I can only guess that it has something to do with the GPL? Who knows. Considering the install base of machines running ext3 and reiserfs (albeit shrinking), you would expect compatibility. Ext2fs is a non-journalized filesystem that doesn't get much use on desktop or servers. I would imagine you could find ext2fs on embedded systems. Most people have at least a 60GB disk in the machines. Try running fsck on 320GB disk, not so much fun. If Theo de Raadt is reading this he'd probably say, "AG get off your dead ass and fix it." He'd probably be correct, as the concern is easily solved by community intervention. Perhaps not very many people care. Just a little surprised that is all.

Overall the experience has been a good one. It reminds me of early days with Unix and Linux. Much learning to be had. Not a bad thing at all. I would encourage more Linux users to take the BSD plunge. There are many powerful security enhancements within BSD. I happen to think Packages and Ports are quite impressive. Not sure I would run BSD on a desktop system, as I'm just very comfortable with Linux. For an asterisk box, or any other server... Absolutely.

*Sigh*, Now if I could just get subversion installed without the nagging ssl.17.0 and crypt.14.0 library errors. Repeat after me.. Never mix -current with -stable.....

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    This page contains a single entry by AG published on September 24, 2009 7:26 AM.

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