Overview and Installation

title: Gentoo I :Overview and Quick Installation
author: Cynorr
category: Gentoo & Linux Server
tag: Gentoo Tutorial
date: 2015-07-01
toc: true

Intruction

Overview

Gentoo is a fast, modern mate-distrubution with a clean and flexible design, which is build around free software and doesn't hide from its user what is beneath the hood. Portage, the package maintance system which the Gentoo use, is written in Python, meaning the user can view and modify the source code. Gentoo packaging system uses source code and configuring Gentoo happens with regular text file. In other words, openness everwhere. Welcome to the world of choice and performance.

Quick Installation

In the process of installation, we are provided with GCC, bash and some specific tools, which makes fresh man daunted. In order to help fresh man build their confidence, this paper provide a quick installing tutorial, following which we can build a light version of Gentoo in 2 hours.

Good Luck!

Installation Structrue

Light Version List

------Configure------	------Value------
Boot Media	Minial installation CD
Stage Archives	stage3
Boot	grub2
Partitions	GPT
Init	openRC
Desktop	xfce

Preparation

• Bootable CD
• U disk with stage3
• Ethernet Network

Steps

• 1.File System: After step 1, we will have base linux environment and chroot
• 2.Configure the System: After step 2, most necessary configuration files will have been configured
• 3.Portage & Kernel: After step 3, the portage is ready to use and the linux kernel is installed
• 4.Bootloader: After step 4, we can boot the gentoo without the Installation CD
• 5.Desktop: After step 5, we will have graphical environment and xfce desktop environment

---

Step1: File System

Preparing the disk

Firstly, we split the full disk into several partitions using GPT partitioning technology.

parted is a popular and powerful tool to split the disk into partitions. Fire up parted aginst the disk (in our example, we use /dev/sda)

root # parted /dev/sda

type p to display the disks' current partition configuration

(parted) p                                                                
Model: ATA PLEXTOR PX-128M6 (scsi)
Disk /dev/sda: 128GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name      Flags
 1      1049kB  211MB   210MB   fat16        EFI
 2      211MB   479MB   268MB   ext2         BOOT
 3      479MB   16.6GB  16.1GB  ext4         ROOT
 4      16.6GB  43.4GB  26.8GB  ext4         USR
 5      43.4GB  108GB   64.4GB  ext4         HOME
 6      108GB   128GB   20.2GB               UNTITLED

First of all, we should set the disk partition list label as gpt

(parted) mklabel gpt

Then, tell parted that the size unit we work with is MB

(parted) unit mib

Now create a 200 MB partition as EFI loader partition. Use the mkpart command for this, and inform parted to start from 1 MB and end at 201 MB (creating a partition of 2 MB in size).

(parted)mkpart primary 1 201
(parted)name 1 EFI
(parted)p

Model: Virtio Block Device (virtblk)
Disk /dev/sda: 20480MiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
  
Number   Start      End      Size     File system  Name   Flags
 1       1.00MiB    201.00MiB  200.00MiB              EFI   

Important: Make sure the label "EFI" is upper case, which can be recoginzed by loader when booting.
Then, do the same for other partitions, my partition scheme likes following, in which the usr partition is recommended to be larger than 20GiB and be split separately.

Number  Start   End     Size    File system  Name      Flags
 1      1049kB  211MB   210MB   fat16        EFI
 2      211MB   479MB   268MB   ext2         BOOT
 3      479MB   16.6GB  16.1GB  ext4         ROOT
 4      16.6GB  43.4GB  26.8GB  ext4         USR
 5      43.4GB  108GB   64.4GB  ext4         HOME
 6      108GB   128GB   20.2GB               UNTITLED

Applying proper filesystem to these partitions

root # make.vfat /dev/sda1
root # make.ext2 /dev/sda2
root # make.ext4 /dev/sda3
root # make.ext4 /dev/sda4
root # make.ext4 /dev/sda5

Installing the Stage3
First mount the disk and U disk with stage3, type fdisk -l to check the U disk partition( our example is /dev/sdb1)

mount /dev/sda2 /mnt/gentoo

mkdir /mnt/gentoo/boot
mount /dev/sda1 /mnt/gentoo/boot

mkdir /mnt/gentoo/usb
mount /dev/sdb1 /mnt/gentoo/usb

Then copy the stage3 file to root directory and unpack in root directory

root # cd /mnt/gentoo/
root # cp usb/stage3-*.tar.bz2 ./
root # tar xvjpf starge3-*.tar.bz2

Chroot
We need to copy the network configuration file and mount some specfic system partition before chrooting.

root # cp -L /etc/resolv.conf /mnt/gentoo/etc/
root # mount -t proc proc /mnt/gentoo/proc
root # mount --rbind /sys /mnt/gentoo/sys
root # mount --rbind /dev /mnt/gentoo/dev

Then chroot and reload the system environment variables

root # chroot /mnt/gentoo /bin/bash
root # source /etc/profile

Step2 Configuring the System

Set the password

root # passwd

To optimize Gentoo, it is possible to set a couple of variables which impact Portage behavior. All those variables can be set as environment variables. To keep the settings, Portage reads in the /etc/portage/make.conf file, a configuration file for Portage.

Fire up an editor (without vim here, we use nano) to alter the optimization variables.

root # nano -w /etc/portage/make.conf

Configuring the compile options

A first setting -march= flag, which specifies the name of the target architecture. A common used value is native as that tell the compiler to select the target architecture of current system.

CFLAGS="-march=native -O2 -pipe"
CXXFLAGS="${CFLAGS}"

The MAKEOPTS variable defines how many parallel compilations should occur when installing a package. A good choice is the number threads in the system plus one. For instance, the hyperthread i5-3230M with 4 threads( 2 cores), should set 5 parallel compilations.

MAKEOPTS="-j5"

Configuring the USE flag
USE is one of the most powerful variables Gentoo provides to its users. Several programmes can be compiled with or without optional support for certain items. Most of xfce desktop users will want to set the following:

USE="X dbus jpeg lock session startup-notification thunar udev -gnome -kde -minimal -qt4

**UEFI configuration

GRUB_PLATFORMS="efi-64"

Selecting mirrors
In order to download source code quickly it is recommended to select a fast mirror. we should surf Gentoo mirror list and search for a mirror that is close to the system's physical location.
First back to boot installing CD environment, which provided a nice tool called mirrorselect:

root # exit

then select the fast mirror by direction key and Enter.

root # mirror -i -o >> /mnt/gentoo/etc/portage/make.conf
root # mirror -i -r -o >> /mnt/gentoo/etc/portage/make.conf

Final chroot again

root # chroot /mnt/gentoo /bin/bash
root # source /etc/profile

Select Profile & Locale
We select default/linux/amd64/13.0/desktop without gnome or kde, since we will use xfce desktop.

root # eselect profile list
root # eselect profile set 3

It is now time to set the system-wide locale settings. We Strongly suggest to use at least one UTF-8 locale because some applications may require it. Here, we use en_US.utf-8

root # eselect locale list
root # eselect locale set 239

Configuring the Network
In this tutorial, we use dhcp. We specfic the dhcp settings right now and install dhcp after syncing the portage tree.
First check the net port by typing ifconfig:

root # ifconfig

enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.101  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::fabc:12ff:fe80:ada3  prefixlen 64  scopeid 0x20<link>
        ether f8:bc:12:80:ad:a3  txqueuelen 1000  (Ethernet)
        RX packets 81407  bytes 116649996 (111.2 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 46215  bytes 3370975 (3.2 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 3144  bytes 1874421 (1.7 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3144  bytes 1874421 (1.7 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

The enp2s0 is the Ethernet port flag, set the connecting method as dhcp

root # echo "config_enp2s0=`dhcp`" > /etc/conf.d/net

To have the network interfaces activated at boot, they need to be added to the default runlevel.

root # cd /etc/init.d/
root # ln -s net.lo net.enp2s0
root # rc-update add net.enp2s0 default

Configuring the fstab
Under Linux, all partitions used by the system must be listed in /etc/fstab, the /boot and /root partitions must be mounted automatically.

nano -w /etc/fstab

Below is a example of an /etc/fstab file:

/dev/sda1   /boot        ext2    defaults,noatime     0 2
/dev/sda2   /            ext4    noatime              0 1

/dev/cdrom  /mnt/cdrom   auto    noauto,user          0 0

Step3: Portage & Kernel

Installing a portage snapshot
A Portage snapshot is a collection file that inform portage what software title are availabe to use, which profiles the adminintractor can select, etc.

root # emerge-webrsync
root # emerge --sync

Configuring the Kernel
First installing the source:

root # emerge gentoo-sources

We use genkernel to configure the kernel to automatically build the kernel right here, and more information and knowledge about kernel will be following chapter.

root # emerge genkernel
root # genkernel all

Step4: Bootloader

The bootloader is responsible for firing up the Linux Kernel upon boot-without it, the system would not know how to proceed when the power button has been pressed.

GRUB2 is provided through the sys-boot/grub package:

root # emerge grub efivar

Next, install the necessary GRUB2 files in /boot/efi, which is separate partition with fat32/fat16 filesystem. Assuming the first disk is /dev/sda, the following command will do this :

root # grub2-install --target=x86_64-efi --efi-directory=/boot/efi

Final, generate the final GRUB2 configuration, run the grub2-mkconfig command:

root # grub2-mkconfig -o /boot/grub/grub.cfg

Reboot directly, and add you UEFI path manually or automatically.

root # reboot

Step5: Desktop

At first, we should install X-server. Xorg is the X Window server which allows users to have a graphical environment.

root # emerge xorg-drivers
root # emerge xorg-x11

Xfce is a fast lightweight but full-featured desktop environment.
xfce

root # emerge xfce4-meta xfce4-notifyd xfce4-panel xfce4-terminal

lxdm loginer
lxdm is one of the login manager, Simple Login Managert.

root # emerge lxde-base/lxdm

Making lxdm / xfce autoboot

root # vim /etc/conf.d/xdm

Set DISPLAYMANAGER as lxdm, and add xdm to autoboot list:

root # rc-update add xdm default

Install dbus and set it autoboot, otherwise slim can't wake xfce up.

root # emerge dbus
root # rc-update add dbus default
root # /etc/init.d/dbus start

Final make lxdm launch xfce, specify the configurations file of lxdm.
Following are some necessary settings of /etc/lxdm/lxdm.conf

session=/usr/bin/startxfce4
autologin=cyno

Step6: Add non-root user

root # useradd -d /home/cyno -m cyno
root # passwd cyno
root # usermod -G wheel,audio cyno
root # gpasswd -a cyno wheel
root # chmod +s /bin/su