A Walk Through the Gentoo Linux Install Process

A Walk Through the Gentoo Linux Install Process 352

Posted by timothy on Tuesday April 09, 2002 @02:03PM from the ingentoous dept.

Anonymous American (Sherman Boyd) writes: "I was looking for a flexible, powerful distribution that makes it easy to build a 'custom' Linux box that meets my exacting specifications. I think I found it. Gentoo Linux has just released version 1.0 of their innovative meta-distribution and to celebrate I decided to throw it on my laptop and write this article based on my experiences." And good news for anyone interested in trying Gentoo: yesterday, Daniel Robbins announced the release of version 1.1a. Read on for AA's detailed look at putting Gentoo on his machine -- Gentoo has a different style than today's typical distributions, and it bears some explanation.

Gentoo solved many problems for me. Some distros install everything, whether you really need it or not. Not Gentoo; other than the base packages required for Linux to run, the only software installed on the system is the software you put there. Gentoo resolves dependencies automatically, eliminating RPM prerequisite hell. As an added bonus I got something I wasn't even expecting. Speed. Blinding, blazing, incredible speed.

The main advantage to the Gentoo distribution is Portage, a python-based ports system similar to BSD ports. For those of you unfamiliar with BSD ports, Portage is a package management tool that downloads and installs source instead of precompiled packages. When I need a program I download, install and compile it with one command:

emerge nmap

The above will download the nmap source code, compile and install it. Of course this method is slow, but it has its rewards. You can also opt to use prebuilt binaries if you are not extremely patient. It took me five hours to get the base Gentoo installed on my PIII with 128 megs of ram. It wasn't a big deal as I had other things to do, but I would like to see the installation process optimized so that it doesn't require any babysitting.

Gentoo is running two of my mission-critical servers right now, I consider it to be stable and mature. A warning, though: this is not a distribution for dummies. This is bare metal Linux, powerful and dangerous. If you do something without thinking you may fall into a bucket of pain.

Let's begin my story.

I download the iso from http://www.ibiblio.org/gentoo/releases/build /. There is a choice of install images here. My favorite way of installing Gentoo is to compile everything, a time consuming process. This method requires a slim 16-meg iso. You may want to grab an iso with pre-built binaries to speed things up, however. This fat iso weighs in at 103 meg. I download the big one with the prebuilt binaries even though I won't use them -- just in case.

I boot my laptop with my shiny new Gentoo CD. The Gentoo install uses isolinux by Peter Anvin. I like the fact that they don't obscure it, giving credit where it is due. It boots quickly and there is a PCI autodetection process, it shouldn't find much on my laptop. Interesting, it loads a SCSI module. Perhaps it has detected my IDE CD burner. Usually this will detect any PCI NIC cards that are installed, but it does not detect my PCMCIA device (of course). After the PCI detection I get a command prompt. I use nano (a small text editor) to open up install.txt, the excellent install doc. Usually these docs are sufficient but the latest ones can be found here:

http://www.gentoo.org/doc/build.html

Keeping the install doc open in this virtual terminal, I hit alt-f2 to open a new one. I begin by loading the pcmcia drivers and installing networking. This is all done at the command line ( insmod, ifconfig, route, dhcpcd, etc.). I use nano to add my DNS servers to /etc/resolv.conf. A word of caution; get in the habit of always using the -w switch with nano. If you do not use the -w switch nano's word wrap feature will jack up your config files. I ping a reliable site, networking is up!

Next I partition my system using fdisk. I choose a simple layout with a swap partition, a root partition and a small boot partition. The boot partition remains unmounted during use, a nice precaution. For filesystems you have a choice of ext2, ext3, ReiserFS and XFS. In my personal experience I've noticed that Reiser performance really rocks when combined with SCSI drives, but as this is an IDE system I think I'll go with XFS. Besides, the XFS tools seem to be a lot more mature than the offerings from Reiser. I format and mount the partitions from the command line creating a /mnt/gentoo directory. I then untar the root filesystem; here I have the choice of the small tarball that requires you to compile everything or a larger tarball that contains pre-built binaries. If you untar the big guy you are almost finished with your install at this point. Using chroot and some scripts you chroot the /mnt/gentoo directory. From this point on you are operating under your new gentoo system.

The first thing I do under my chrooted system is issue this command:

emerge rsync

This downloads the latest version of the portage tree. The portage tree is found under /usr/portage and contains the ebuild scripts used to compile/install programs. Currently there are over 1000 up to date emerge sripts. Next I edit /etc/make.conf, here I can choose compiler settings. I optimize everything for i686. Now it's time to build the GNU compiler and libraries. I run the bootstrap script and leave for lunch. On my PIII 500 the boostrap process takes 2 hours and 2 minutes.

The second emerge command I issue is:

emerge system

Now emerge downloads, compiles and installs my base system packages. I sit back, relax and take the time to fax my legislators a rant about the DMCA. One hour and 30 minutes later it is finished.

Now it is time to download and install the kernel. First I make a link updating my timezone, and then I issue another emerge command:

emerge linux-sources

This grabs the latest kernel, 2.4.19, and drops the source in /usr/src/linux. Ten minutes have elapsed. Now comes the fun, compiling your kernel. That's right, everyone who installs Gentoo compiles their own kernel as a matter of process. I like this. There are some distributions out there that actually say you should never compile your own kernel. Shame on them. I use make menuconfig and the standard commands to compile my kernel. Since Gentoo uses devfs I select /dev file system support and I am also careful to compile in support for XFS. I don't have the kernel mount devfs automatically at boot as the Gentoo startup scripts take care of this for me. Virtual Memory file system support is also enabled.

At this point in time I get to choose a logger. My choices are sysklogd, syslog-ng or metalog. I choose metalog, because it's got the coolest name. I download, compile and install it using a single command:

emerge metalog

XFS has some nice utilities, I better install those. I have some other essential programs to install, and I'm feeling a bit lazy so I chain them all in one big command.

emerge xfsprogs;emerge bitchx;emerge vim;emerge links

At this point I'm feeling pretty 7-Up. I edit my /etc/fstab file, my /etc/hostname file and /etc/hosts. The passwd command is run to set the root passwd. I add my NIC module to the file /etc/modules.autoload and edit /etc/conf.d/net. conf.d/net allows me to configure my IP address and settings, default gateway and alias. I take a look at /etc/init.d/net.eth0, even though I don't need to edit it. I can then add it to the startup script using this command:

rc-update add net.eth0 default

This adds the script to the default runlevel to be executed at startup. Startup scripts are another place Gentoo really shines. The startup scripts have a system of dependencies. For example net.eth0 can depend on pcmcia. The pcmcia drivers get loaded before net.eth0 - this is good.

Next I install grub. If you haven't used grub before, it's nice. You can boot to a kernel directly from the grub shell, without having to edit a config file. lilo is still available, for those of you who prefer it. Gentoo likes to let you make the decisions.

I exit my chrooted shell and unmount all directories. Reboot! Gentoo comes up and the install process is complete.

The Gentoo install process has taught me a lot about Linux, and I like the fact that the command line is embraced, instead of hidden behind gui or scripts. I also like the speed (which is debatable since all I can supply is anecdotal evidence). I wasn't too happy about waiting five hours for everything to compile, but I think it was worth it. I can tell you it compiles and greps noticeably faster than other distros I have run on the exact same machines. I really enjoy using portage, and the packages seem to stay up to date -- if not bleeding edge. This is not a conservative distribution like Debian, however I like the aggressive and intelligent direction gentoo is taking.

If you are considering trying out Gentoo I highly suggest #gentoo on irc.openprojects.net. Also subscribe to the mailing lists found at www.gentoo.org. The Gentoo community has helped me out of several jams in the past, I think they will treat you good too.

While writing this, I received help from a lot of people. However I would like to personally thank the people I ripped off word for word. Thanks notafurry of www.kuro5hin.org for your pointed help with the stilted second paragraph and thank you Ween from #gentoo on openprojects.net for your clean description of portage.

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