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<?xml version='1.0' encoding="UTF-8"?>
<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
<guide link="migration-guide.xml">
<title>A Developers view on Gentoo Installation</title>
<author title="Senior Developer Manager">
<mail link="spider@gentoo.org">Spider</mail>
</author>
<author title="Editor">
<mail link="peesh@gentoo.org">Jorge Paulo</mail>
</author>
<abstract>
This guide shows a hands-on documented installation by a Senior
developer in the Gentoo project. It is meant to show tips, hints and how
the flexible installation process is used by developers. Perhaps it will
give you some insight in what the "more experienced users" do that others
don't when reinstalling Gentoo Linux.
</abstract>
<version>0.6.1</version>
<date>7 Jun 2003</date>
<chapter>
<title>Introduction</title>
<section>
<title>The authors notes</title>
<body>
<p>
Let me introduce my system first. I run an AMD Athlon Tbird at 1.1 GHz,
two hard-drives on two different IDE controllers, both on the same
main-board. My current system is all contained in and installed on one
hard-drive, and my target is on another. I have some data that I wish to
keep on the target device, so a full reinstall is not possible. I also
want to keep this in a "flawless" manner: no service disruptions unless
it is really necessary.
</p>
<warn>
I aim this at experienced users, who know better than to blindly copy
and paste commands from the documentation into their system. Please,
don't do anything hasty. And remember <e>backups</e>!
</warn>
</body>
</section>
<section>
<title>The authors system</title>
<body>
<p>
My current system is installed on <path>/dev/hde3</path> with
<path>/home</path> existing on <path>/dev/hde6</path>. My target
<path>/boot</path> is on <path>/dev/hda1</path> and the <path>/</path>
is on <path>/dev/hda3</path>. To keep the disruptions to a minimum,
<path>/home</path> will remain unchanged. I also have a separate
partition at <path>/mnt/build</path> that contains the portage tree,
temporary build files and the distfiles. </p>
</body>
</section>
<section>
<title>Goals</title>
<body>
<p>
Since I call myself a "hacker" at core, I can't really do something like
this without learning something from the experience. (No, my current
system is not so damaged that I'm forced to reinstall.) So, I shall also
try some "new" things that are best off on a clean slate.
</p>
<p>
The first of these will be JFS as a change from my normal choice
of ext3.
</p>
<p>
I will also change my default optimizations from <c>-O2</c> to
<c>-Os</c> to see if I can reduce a problem I've had recently with large
memory footprints.
</p>
</body>
</section>
<section>
<title>Pre setup</title>
<body>
<p>
I assume you are all familiar with the "normal" <uri link="http://www.gentoo.org/doc/en/gentoo-x86-install.xml">installation guide</uri>. If
you have doubts about this, please take the time to read it again as I
will try to avoid being redundant in this document.
</p>
<p>
First off, I'll wipe the partitions I'm going to install to. This is
simple but a bit time-consuming:
</p>
<pre caption = "Clearing all data from the partitions">
# <i>dd if=/dev/zero of=/dev/hda1 bs=512</i>
dd: writing `/dev/hda1': No space left on device
48133+0 records in
48132+0 records out
# <i>dd if=/dev/zero of=/dev/hda3 bs=512</i>
dd: writing `/dev/hda3': No space left on device
6104701+0 records in
6104700+0 records out
</pre>
<p>
Then I will initialize the partitions "as I want them".
<path>/boot</path> on ext2. Stable. Classic. No frills.
</p>
<pre caption = "Initialising the boot partition">
# <i>mkfs.ext2 /dev/hda1</i>
</pre>
<p>
I need the JFS tools on the host to build my target system.
</p>
<pre caption = "Installing the JFS tools on the host system">
# <i>emerge sys-apps/jfsutils</i>
# <i>mkfs.jfs -L root_jfs /dev/hda3</i>
mkfs.jfs version 1.1.2, 25-Mar-2003
Warning! All data on device /dev/hda3 will be lost!
Continue? (Y/N) <i>Y</i>
-
Format completed successfully.
3052350 kilobytes total disk space.
</pre>
<p>
Now I am going to setup the basic premises for a Gentoo installation,
mount the necessary devices, etc. At this point I had to
rebuild my kernel with JFS filesystem support. This was done by simply
checking JFS as a kernel module in the filesystems section, then
<c>make dep && make modules && make modules_install</c>.
</p>
<pre caption = "Setup Target Premises">
# <i>mkdir /mnt/target</i>
# <i>mount /dev/hda3 /mnt/target</i>
# <i>mkdir /mnt/target/boot</i>
# <i>mount /dev/hda1 /mnt/target/boot</i>
# <i>df -h /mnt/target</i>
# <i>mkdir /mnt/target/mnt/build</i>
# <i>mount --bind /mnt/build /mnt/target/mnt/build</i>
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 2,9G 524K 2,9G 1% /mnt/target
</pre>
</body>
</section>
</chapter>
<chapter>
<title>Beginning installation</title>
<section>
<title>Stage 2</title>
<body>
<p>
Now that we have the basic preparations done, we need a stage build.
Since I want <c>-Os</c> instead of <c>-O2</c> I will not use a stage3
build, which I would normally use. Instead I fetch the latest stage2
from <uri>http://www.ibiblio.org/gentoo/experimental/x86/stages/</uri>
to test them.
</p>
<note>
I don't want to build my compiler/base with -Os, but prefer the stable
and known options, so I go with stage2 to shorten time.
</note>
<pre caption = "Installing and chrooting into a stage2 environment">
# <i>cd /mnt/target && tar -xvjpf /root/stage2-x86-1.4_pre20030407.tar.b
z2</i>
# <i>mount -t proc proc /mnt/target/proc</i>
# <i>cp /etc/resolv.conf /mnt/target/etc/resolv.conf</i>
# <i>chroot /mnt/target /bin/bash</i>
# <i>env-update ; source /etc/profile</i>
</pre>
<p>
Then I setup <path>/etc/make.conf</path> the way I want it. Here is my
current list of USE flags:
</p>
<pre caption = "USE flags">
apm avi encode libg++ libwww mikmod mpeg ncurses nls pdflib
qtmt quicktime spell xml2 xv zlib gdbm berkdb slang readline
aalib tcltk java guile X sdl gpm tcpd pam perl python esd imlib
gtk motif mozilla gphoto2 ldap cdr crypt alsa oggvorbis gnome
gpg gpgme bonobo oss ssl xmms 3dnow mmx opengl tiff png jpeg
smooth truetype gif ggi samba xv gtkhtml dvd -lirc -gtk2 -arts
-qt -kde -cups -sse -tetex -doc -svga
</pre>
<p>
I also set the <c>CHOST</c>, <c>CFLAGS</c> and other variables that
need to be altered.
</p>
</body>
</section>
<section>
<title>Portage tree and builds</title>
<body>
<p>
I should point out that I have not done an <c>emerge sync</c> yet
and will not do so. I will simply re-use my old configuration where the
portage tree and build area are on a different partition. This data
changes often and so deserves it's own partition.
</p>
<pre caption = "Altering /etc/make.conf">
PORTAGE_TMPDIR=/mnt/build
DISTDIR=/mnt/build/distfiles
PKGDIR=/mnt/build/packages
PORTDIR_OVERLAY=/usr/local/portage
GENTOO_MIRRORS="ftp://ftp.sunet.se/pub/Linux/distributions/gentoo/ http://gentoo
.oregonstate.edu/"
MAKEOPTS="-j1"
</pre>
<note>
The <c>MAKEOPTS=-j1</c> gives less overhead for background compiling, which is
what I want. I don't need the overhead of max performance. I want updates
to go in the background and behave well. At least until the system is
100%.
</note>
<pre caption = "Prepare the Portage tree">
# <i>cd /usr; rm -fr portage; ln -s /mnt/build/gentoo-x86 portage</i>
</pre>
<note>
The <path>/mnt/build/portage</path> directory is where things are built,
I store the Portage tree in <path>/mnt/build/gentoo-x86</path>.
</note>
</body>
</section>
<section>
<title>emerge system</title>
<body>
<p>
And now it is time to <c>emerge system</c> and hope for the best.
</p>
<pre caption = "Progressing from stage2 to stage3">
# <i>time nice -n +15 emerge -u system</i>
/bin/sh: line 1: gluUnProject._man: No space left on device
:79: I/O error on output
make[5]: *** [gluUnProject._man] Error 1
make[5]: Target `all' not remade because of errors.
make[5]: Leaving directory `/mnt/build/portage/xfree-4.2.1-r2/work/xc/doc/man/GLU'
...
...
real 90m11.657s
user 74m18.390s
sys 8m19.480s
</pre>
<p>
Just great. After deleting some distfiles (the files in
<path>/mnt/build/distfiles</path>) I freed about 1.2 Gb of space.
At this point I regret not using ccache. Time to enable that :)
</p>
<pre caption = "Enabling ccache">
<codenote>This goes in /etc/make.conf</codenote>
FEATURES="sandbox ccache"
CCACHE_SIZE="1G"
<codenote>This is in the (chrooted) shell again</codenote>
# <i>cat /etc/env.d/99ccache</i>
CCACHE_DIR=/mnt/build/OLD/cache/
</pre>
<p>
And after that disturbance it's back to compiling.
</p>
<pre caption = "Continuing progressing from stage2 to stage3">
# <i>time nice -n +15 emerge -u system</i>
real 106m5.162s
user 71m40.320s
sys 10m41.320s
</pre>
</body>
</section>
<section>
<title>System part 2</title>
<body>
<p>
After this I setup the timezone and emerge the following packets:
</p>
<pre caption = "Emerging necessary packets">
# <i>emerge sysklogd vanilla-sources jfsutils</i>
</pre>
<p>
Now comes the fun part. Since I have a working kernel running and
configured correctly for my system I just copy the host's
<path>.config</path>, issue a <c>make oldconfig</c> and then do a quick
<c>make menuconfig</c> to check that I have all necessities.
</p>
<pre caption = "Compiling the kernel">
# <i>nice -n +15 make oldconfig dep bzImage modules</i>
</pre>
<note>If you added JFS as a module, don't forget to change that to
built-in or your system will fail to find root at the first boot.</note>
<p>
By this time, I have the same kernel built that I have for the host
system, which is a good thing in case something does `uname -r` to check
the system I'm building with. Of course, you could argue that such
things are bad and should be removed, but sometimes it is justified.
</p>
<p>
After installing the kernel as normal, it's time to make sure I get the
right modules built and installed. Checking the host system and
installing them on the target is a good start.
</p>
<pre caption = "Checking the kernel modules">
# <i>qpkg -v -f /lib/modules</i>
media-libs/svgalib *
media-sound/alsa-driver *
media-video/nvidia-kernel *
sys-apps/i2c *
sys-apps/lm_sensors *
sys-apps/pcmcia-cs *
sys-kmods/lm_sensors *
</pre>
<p>
A bit messy as you can see, but the general populace is <i>i2c</i>
(requirement of <i>lm_sensors</i>), <i>pcmcia-cs</i> ,
<i>alsa-driver</i> and <i>nvidia-kernel</i>. Let's start with
<i>pcmcia-cs</i> and <i>nvidia-kernel</i> since those are the most
important ones for my system right now.
</p>
<pre caption = "Installing the necessary packages">
# <i>nice -n +20 emerge -pv pcmcia-cs nvidia-kernel lm_sensors</i>
# <i>ALSA_CARDS="trident dummy" nice -n +15 emerge alsa-driver -pv</i>
</pre>
<note>You can add the variable ALSA_CARDS to <path>/etc/make.conf</path> for this setting to be permanent.</note>
<p>
At this time I have not done any configuration at all, but I'd better
do that soon. "Or else" :). I'll start by installing a usable editor
and some miscellaneous console things that I feel I need. I will also
install a mail-server and a cron daemon. (Mail-server first to satisfy
the cron daemons need for a mail-server.)
</p>
<pre caption = "Installing some tools I need">
# <i>nice -n +15 emerge lftp vim screen postfix gnupg -v</i>
# <i>nice -n +15 emerge fcron </i>
</pre>
<p>
Oops, I forgot the ntp daemon, wireless-tools and SpamAssassin:
</p>
<pre caption = "Installing some tools I forgot">
# <i>nice -n +20 emerge ntp wireless-tools Mail-SpamAssassin</i>
</pre>
</body>
</section>
</chapter>
<chapter>
<title>System configuration</title>
<section>
<title>Service enabling</title>
<body>
<p>
In this chapter I'll do the basic configuration that I ignored
previously. To avoid problems, I will start by enabling the services (so
I won't forget it) and go on by configuring each service in it's own
section after that.
</p>
<pre caption = "Activating the initscripts">
# <i>rc-update add sysklogd default</i>
# <i>rc-update add fcron default</i>
# <i>crontab /etc/crontab</i>
# <i>rc-update add alsasound boot</i>
# <i>rc-update add sshd default</i>
# <i>rc-update add lm_sensors default</i>
# <i>rc-update add pcmcia default</i>
# <i>rc-update add ntp default</i>
# <i>rc-update add net.eth0 default</i>
# <i>rc-update add spamd default</i>
</pre>
<p>
This concludes the services section; onwards to configuration.
</p>
</body>
</section>
<section>
<title>System logger configuration</title>
<body>
<p>
I have a little special configuration for my syslogger; namely that I
always wish to keep parts of my logs on two open terminals. Setting
this up is generally quite simple unless you use Metalog, in which case
you have to do extra hacks. See the Metalog documentation for that. Here
is a partial diff -u against the original conf to my personalized
settings.
</p>
<pre caption = "Changes made against the original syslog config">
-#cron.* /var/log/cron.log
+cron.* /var/log/cron.log
+*.emerg /dev/tty9
+*.info;kern.none;mail.none;authpriv.none;cron.none; /dev/tty10
+kern.* /dev/tty11
</pre>
</body>
</section>
<section>
<title>ALSA setup</title>
<body>
<p>
Setting up alsa the first time can be a hassle. Therefore, I'm just
migrating my own settings from the old, proven and working system onto
my new partition. I'll post the config diff here for your dubious
pleasure.
</p>
<pre caption = "Diff against the default /etc/modules.d/alsa">
+alias snd-card-0 snd-trident
+alias sound-slot-0 snd-card-0
+
+alias snd-card-1 snd-dummy
+alias sound-slot-1 snd-card-1
</pre>
<p>
Just don't forget to run alsamixer once you have rebooted. For my part
I just copied <path>/etc/asound.state</path> onto the new partition,
retaining all settings perfectly.
</p>
</body>
</section>
<section>
<title>Sensors configuration</title>
<body>
<p>
Unfortunately you cannot do this properly from inside a chroot since
it depends on modules being loaded and what not. You will have to redo the
configuration in your clean booted system at a later moment.
</p>
</body>
</section>
<section>
<title>PCMCIA configuration</title>
<body>
<p>
When I first did this in Gentoo it was something of a black art. I pulled the config from my then working LFS partition (that was
adapted from RedHat). This config is still in my system, albeit a bit
different now. So, I figure it is time to restart configuring it
completely and see what can be done about it.
</p>
<p>
On my system <i>eth0</i> is my internal network, on a normal NIC, and <i>eth1</i> is my external network, on a PCMCIA wireless NIC.
</p>
<p>
First, I copy over <path>/etc/init.d/net.eth0</path> script to
<path>/etc/init.d/net.eth1</path>. Then I set <i>need pcmcia</i> in
the <path>net.eth1</path> script. I also modify <path>net.eth0</path>
to read <i>before pcmcia</i> instead of <i>use pcmcia</i>. This way I
won't be stuck without a network internally if the pcmcia card is down
or restarted.
</p>
<p>
The default <path>/etc/conf.d/pcmcia</path> was ok for me, which meant I
have yet to fix <path>/etc/conf.d/net</path> and the pcmcia config.
</p>
<p>
Configuring pcmcia networking is pretty straightforward once you
understand it. Open <path>/etc/pcmcia/wireless.opts</path> and set it
up according to how the documentation inside that configuration
explains. Don't forget adding it to the default runlevel.
</p>
<pre caption = "Adding net.eth1 to the default runlevel">
# <i>rc-update add net.eth1 default</i>
</pre>
<p>
Otherwise you may be without a network.
</p>
</body>
</section>
<section>
<title>NTP configuration</title>
<body>
<p>
Setting up NTP is really quite simple. First I want to make sure that
ntp actually syncs with servers continuously, not at boot. That means
disabling ntpdate and using the normal service. Here is the resulting
<path>/etc/ntp.conf</path>:
</p>
<pre caption = "/etc/ntp.conf">
logfile /var/log/ntpd.log
driftfile /var/lib/misc/ntp.drift
server ntp1.sp.se prefer
server ntp1.sth.netnod.se
server ntp.lth.se
restrict default ignore
restrict 192.168.0.0 mask 255.255.255.0 notrust nomodify notrap
</pre>
<p>
I also take a moment to edit <path>/etc/init.d/ntpd</path> so it has
an <i>after net.eth1</i> in it. This, together with setting
<c>NTPDATE_CMD="ntpd"</c> in <path>/etc/conf.d/ntpd</path>, assures me
that most of my timing issues will be gone.
</p>
</body>
</section>
<section>
<title>SSH configuration</title>
<body>
<p>Unless you wish to change how your SSH configuration works, you can
simply copy <path>/etc/ssh/ssh_config</path> and
<path>/etc/ssh/sshd_config</path> to your target system.</p>
<pre caption = "Copying over SSH configuration">
# <i>cp -p /etc/ssh/*conf* /mnt/target/etc/ssh</i>
</pre>
<warn>Don't mess up the permissions</warn>
</body>
</section>
<section>
<title>Modules setup</title>
<body>
<p>
Setting up module loading the way I want it requires some care. First,
I have to make sure I have all the needed hardware support in my kernel
(I know I do) and I also need to make the alias work nicely. First I
create <path>/etc/modules.d/usb</path> and setup my camera (usb storage,
generic).
</p>
<pre caption = "Configuring usb modules in /etc/modules.d/usb">
alias /dev/sda1 sd_mod
pre-install sd_mod modprobe -k usb-storage;sleep 5s
pre-install usb-storage modprobe -k usb-uhci
</pre>
<p>
Second I setup <path>/etc/modules.d/cdrw</path> to automatically "just
work" and clean up after it's done. I also make sure that ide-cd ignores
the device that is my CDRW (if ide-cd is loaded for that device then
burning won't work).
</p>
<pre caption = "Configuring ide/scsi modules in /etc/modules.d/cdrw">
options ide-cd ignore=hdb
alias scd0 sr_mod
pre-install sg modprobe -k ide-scsi
pre-install sr_mod modprobe -k ide-scsi
pre-install ide-scsi modprobe -k ide-cd
</pre>
<p>
Then, a quick alias for my network to go into
<path>/etc/modules.d/net</path>. Finish off by doing a
<c>modules-update</c>.
<pre caption = "Network alias">
alias eth0 8139too
</pre>
</p>
<pre caption = "Finishing of modules configuration">
# <i>modules-update</i>
</pre>
</body>
</section>
<section>
<title>/etc/fstab setup</title>
<body>
<p>
fstab is well documented all around the net and in our normal
installation instructions, so I'll just add a few notes about
the differences to my settings and the default.
</p>
<pre caption = "/etc/fstab differences">
/dev/cdroms/cdrom0 /mnt/cdrom iso9660 noauto,ro,users,unhide 0 0
/dev/sda1 /mnt/usb vfat noauto,defaults,users 0 0
</pre>
<p>
The "users" allows users to mount and unmount; unhide will show even
hidden files on the cdrom. <path>/dev/sda1</path> is in my case a
digital camera on usb-storage, as configured earlier in the modules
section.
</p>
<p>
Another thing to setup is to have your "old" system mounted ( say on
<path>/mnt/old</path>). This will allow for simple checks
between the systems once you have your new system up and running.
</p>
</body>
</section>
<section>
<title>Misc settings</title>
<body>
<p>
The <path>/etc/rc.conf</path> probably doesn't need much mention here.
Neither does grub configuration.
</p>
</body>
</section>
</chapter>
<chapter>
<title>Migrating settings</title>
<section>
<title>What is migration?</title>
<body>
<p>This chapter will deal with how to move other, non service related
settings to your new system. This includes users, groups, host
identifications and different settings that aren't related to the boot
process of the system.</p>
</body>
</section>
<section>
<title>User migration</title>
<body>
<p>
Now it is time to migrate the user and group data from your old system
into the new one; files to watch out for are:
</p>
<pre caption = "Files concerning user migration">
/etc/shadow
/etc/passwd
/etc/group
/etc/hosts.allow
/etc/hosts.deny
</pre>
<p>
In this case, <c>diff -u</c> is a handy tool to check that you merged
all groups and users. (No, don't just copy things over, doing that might
mean that new users aren't merged properly between Gentoo versions).
</p>
<warn>Don't mess up the permissions</warn>
</body>
</section>
<section>
<title>SSH migration</title>
<body>
<p>
Migrating SSH host settings is a fairly simple, yet important process. If not done, or done incorrectly, scripts and users who depend on your
system will have problems from facing a man in the middle warning and
connections may fail. Copy over the keys to your new system (make sure
you get permissions right):
</p>
<pre caption = "Copying over the SSH keys">
# <i>cp -p /etc/ssh/ssh_host* /mnt/target/etc/ssh</i>
</pre>
<warn>Do not forget the -p option to cp</warn>
</body>
</section>
<section>
<title>X11 configuration</title>
<body>
<p>The most important file is <path>/etc/X11/XF86Config</path>. In many
cases it's okay to just copy it as-is into the new system. However, sometimes you may wish to only back it up and then generate a new config from
scratch. Especially if you have been adding or removing font
configurations or have entries for old hardware left.</p>
<pre caption = "Copying X11 Configuration">
# <i>cp /etc/X11/XF86Config /mnt/target/etc/X11</i>
</pre>
</body>
</section>
<section>
<title>Nethack migration</title>
<body>
<p>Since nethack stores savegames and bones in the
<path>/usr/share/games/nethack</path> directory, we need to copy these
over into the target system. Since it's also runs as setuid games, we need
to preserve permissions.</p>
<pre caption = "Migrating nethack datafiles">
# <i>emerge nethack</i>
# <i>cp -pr /usr/share/games/nethack/save /mnt/target/usr/share/games/nethack</i>
# <i>cp -p /usr/share/games/nethack/bone* /mnt/target/usr/share/games/nethack</i>
</pre>
<note>Dont forget that <path>/home/$USER</path> should be set
read+execute by group, and that <path>${HOME}/.nethackrc</path>
needs to be readable by group games.</note>
</body>
</section>
</chapter>
<chapter>
<title>Software installation</title>
<section>
<title>Required software</title>
<body>
<p>Most systems require far more software than what has been covered
here. For a normal desktop there is usually a myriad of small programs
that are in use from time to time. You will miss many of those when
scripts break or users complain. This chapter will go through some
of the necessary parts of finding software which you may want to install
on your target system.</p>
</body>
</section>
<section>
<title>Finding previously installed software</title>
<body>
<p>There are a few useful tools for identifying commonly used programs.
One is <c>qpkg</c> from the <i>app-admin/gentoolkit</i> package. Another
is <c>epm</c>. For epm you do <c>epm -qf /usr/bin/qpkg</c> to find out
what package "qpkg" belongs to. For qpkg the syntax is <c>qpkg -f /usr/bin/qpkg</c>.
</p>
<p>But above this, there is the <path>/var/cache/edb/world</path> file
where all explicitly installed packages are listed. This file will
contain all packages you've ever installed explicitly through
<c>emerge</c>. In my case it isn't desirable to install all the packages
that are listed in the world file, instead I will use my judgement and
only install parts of it. </p>
<p>
</p>
</body>
</section>
</chapter>
</guide>
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