UNIX & GNU/Linux - Gentoo - Basis for setting it up

In the Linux world, there are two types of distributions.

First the monolithic ones, such as Ubuntu, where you don't have to set anything before using it.

Everything (or almost) is included to begin.

Second, the specific ones, that on calls meta-distributions, where you have to select only packages and options you want to have.

Of course, the first is easier to use for a current usage but there is no optimization at all.

With the second, optimization and selecting packages are the key, but they are very complicated for beginners.

Let's try to deep inside the second one in this Gentoo installation tutorial for beginners.

First of all

We are going to use VirtualBox and Gentoo.

So let's download the VirtualBox virtual machine manager and the Gentoo distribution:

• https://www.virtualbox.org/wiki/Downloads
• https://www.gentoo.org/downloads/

To be exact, we will use:

• VirtualBox 5.1.8.exe
• Gentoo minimal installation x86 (20161115).iso

Setting VirtualBox

It's essential to set up a new virtual machine, because it's likely that a kernel panic will occur in the current process.

So don't be afraid, with a fresh new virtual machine, you won't lose anything because it's always possible to erase it and start again from the beginning.

From VirtualBox > New:

• Name: Gentoo x86 2016.11.15
• Type: Linux
• Version: Gentoo (32-bit)

Next > 1024 MB > Next > Create a virtual hard disk now > Create > VDI (VirtualBox Disk Image) > Next > Fixed size > select 8 GB as file size > Create.

It should take 1 minute to create.

Space for your virtual machine is created.

Let's now add the Gentoo distribution to this virtual machine.

From VirtualBox > select the new VM just created > Right click > Settings > Storage > on the Storage Tree, select Empty under the Controller: IDE.

On the right there is CD-ROM icon, click it.

Choose Virtual Optical Disk File... > select your Gentoo distribution downloaded > OK.

From VirtualBox > select your VM in the list > right click > Start > You are now able to start Gentoo by clicking on the Green arrow > Start > Normal Start.

You have now 15 seconds to press any key when the message will request it.

At this moment, if your mouse cursor has disappeared, don't worry, just click your OS Home key from your computer.

In a moment we will see how to configure your network with VirtualBox, in the SSH server part.

Stay tuned!

Setting Gentoo

Once the Gentoo OS started, it's time to set it up.

The first screen that should appear is a choice to boot from the kernels or options, respectively by pressing F1 or F2 keys.

Press F1 and type the following command for the boot:

gentoo

Press ENTER.

You'll have to choose which keyboard country you depend on.

Then a new prompt will appear after few seconds:

livecd ~ #

This is your new prompt and you can try to list the current directory with a classic:

livecd ~ # ls -la

SSH connection

In order to control your Gentoo directly from another shell (Putty for example) you have to start the SSH server from your Gentoo distribution.

First, it necessary to shutdown your VM to change the network settings, you can do directly from your Gentoo prompt like that:

livecd ~ # shutdown -h now

From VirtualBox

Now that your VM is powered off, you can change your network settings.

From VirtualBox > right click your Gentoo VM > Network > in the Adapter 1 tab, check the Enable Network Adapter > Attached to: Bridge Adapter > just below you should see your network card appear > OK.

Start again your VM.

When you see the livecd prompt, you can type the following command:

livecd ~ # ifconfig

You should see two IPs, the first is the lo (for loopback system), the second enp0s4 (for example, it changes from a computer to another).

So with the second, in our case enp0s4, you can read the IP just after the inet word:

• inet 192.168.0.9 netmask 255.255.255.0 broadcast 192.168.0.255

This IP is then: 192.168.0.9

Starting the SSH server

Still from your Gentoo distribution, type the following command in your prompt:

livecd ~ # /etc/init.d/sshd start

Your SSH server is now started.

Let's change the password by something easy to remember.

Still from your Gentoo VM prompt:

livecd ~ # passwd

Enter the new password "root" and retype it when asked:

livecd ~ # root

Even with the message saying that the password is too short or too simple, it's not important for this tutorial.

Your password is now updated succesfully.

From Putty

Open Putty > Session > on the right, in the Host Name (or IP adress), type 192.168.0.9 > just below, select SSH as Connection type > Open.

You should see a PuTTY security alert telling you that the server's host key is not cached in the registry.

Don't worry with that and click Yes.

Instantly from  your Putty console, you should see a message asking you to enter the login and then the password.

Enter the default login and password (they are the same by default):

login as: root
Password: root

Done!

You can see now the same prompt as in your Gentoo from VirtualBox.

I think it's quite easiest to use Putty in this case.

But of course, it's up to you to continue this tutorial with either your VM or Putty.

Partitioning

Before going further, it's time to partitioning our hard drive.

On Linux, the system is divided in block devices.

They are on the /dev/ directory.

Here /dev/ stands for device.

So all files in /dev/ directory are devices.

You can see for example, in the /dev/ directory, something like this:

brw-rw----  1 root disk    8,   0 Nov 21 21:21 sda

The first letter, on the left, is a "b" meaning block.

The letters "sda" stand for Sata Device A.

Here the "a" means the first Sata Device.

The second device (second hard drive for example) would be "sdb", the third "sdc", etc.

But if we have sda with some numbers, such as sda1, sda2 it's because the number represents the partition number.

Consequently we can assume:

• sda1 is the Sata Device A Partition number 1
• sda2 is the Sata Device A Partition number 2
• sdb1 is the Sata Device B Partition number 1
• And so on.

So we are going now to create partitions on your hard drive.

The main tool for that is fdisk.

So to activate it just type in your prompt:

livecd ~ # fdisk /dev/sda

To show your partitions just write "p" for print:

p

You should see something like this:

Command (m for help): p
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab1508c

Command (m for help):

The main option is of course the help that you can open with the letter "m" for manual:

Command (m for help): m

Help:

  DOS (MBR)
   a   toggle a bootable flag
   b   edit nested BSD disklabel
   c   toggle the dos compatibility flag

  Generic
   d   delete a partition
   l   list known partition types
   n   add a new partition
   p   print the partition table
   t   change a partition type
   v   verify the partition table

  Misc
   m   print this menu
   u   change display/entry units
   x   extra functionality (experts only)

  Script
   I   load disk layout from sfdisk script file
   O   dump disk layout to sfdisk script file

  Save & Exit
   w   write table to disk and exit
   q   quit without saving changes

  Create a new label
   g   create a new empty GPT partition table
   G   create a new empty SGI (IRIX) partition table
   o   create a new empty DOS partition table
   s   create a new empty Sun partition table

So we are going to use some of these options throw this tutorial.

The boot partition

Let's start by create the boot partition by typing the following command:

n      (NEW)
p      (PRIMARY)
1      (PARTITION 1)
ENTER  (2048 MiB by default for the FIRST SECTOR ADRESS)
+100M  (LAST SECTOR SIZE)

Indeed when you type "ENTER" without any number, the default value is applied.

Here the result step by step:

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-16777215, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-16777215, default 16777215): +100M

Created a new partition 1 of type 'Linux' and of size 100 MiB.

By typing "p" again, you'll see the new partition created:

Command (m for help): p
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab6506b

Device     Boot Start     End   Sectors   Size Id Type
/dev/sda1        2048  206847    204800   100M 83 Linux

The swap partition

This partition will be used by the system when you'll run out of memory (RAM).

So to help it, we create this swap partition in order to help the processor to write data on your hard drive when it needs it.

So it's like the RAM but slower.

Let's create it almost like the boot partition but with a size of 1 GiB this time:

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2): 2
First sector (206848-16777215, default 206848):
Last sector, +sectors or +size{K,M,G,T,P} (206848-16777215, default 16777215): +1G

Created a new partition 2 of type 'Linux' and of size 1 GiB.

You are of course free to specify the amount you want but dont' forget that this will be taken from the 8 GiB space allowed at the beginning.

It's of course necessary to select the type with the "t" letter by typing the corresponding value in the list.

To open up the list, type "L" for list then in our case "82" for Linux swap / So (Solaris):

Command (m for help): t
Partition number (1,2, default 2): 2
Partition type (type L to list all types): L

0  Empty             24  NEC DOS           81  Minix / old Lin   bf  Solaris
1  FAT12             27  Hidden NTFS Win   82  Linux swap / So   c1  DRDOS/sec (FAT-
2  XENIX root        39  Plan 9            83  Linux             c4  DRDOS/sec (FAT-
3  XENIX usr         3c  PartitionMagic    84  OS/2 hidden C:    c6  DRDOS/sec (FAT-
4  FAT16 <32M        40  Venix 80286       85  Linux extended    c7  Syrinx
5  Extended          41  PPC PReP Boot     86  NTFS volume set   da  Non-FS data
6  FAT16             42  SFS               87  NTFS volume set   db  CP/M / CTOS / .
7  HPFS/NTFS/exFAT   4d  QNX4.x            88  Linux plaintext   de  Dell Utility
8  AIX               4e  QNX4.x 2nd part   8e  Linux LVM         df  BootIt
9  AIX bootable      4f  QNX4.x 3rd part   93  Amoeba            e1  DOS access
a  OS/2 Boot Manag   50  OnTrack DM        94  Amoeba BBT        e3  DOS R/O
b  W95 FAT32         51  OnTrack DM6 Aux   9f  BSD/OS            e4  SpeedStor
c  W95 FAT32 (LBA)   52  CP/M              a0  IBM Thinkpad hi   eb  BeOS fs
e  W95 FAT16 (LBA)   53  OnTrack DM6 Aux   a5  FreeBSD           ee  GPT
f  W95 Ext'd (LBA)   54  OnTrackDM6        a6  OpenBSD           ef  EFI (FAT-12/16/
10  OPUS             55  EZ-Drive          a7  NeXTSTEP          f0  Linux/PA-RISC b
11  Hidden FAT12     56  Golden Bow        a8  Darwin UFS        f1  SpeedStor
12  Compaq diagnost  5c  Priam Edisk       a9  NetBSD            f4  SpeedStor
14  Hidden FAT16 <3  61  SpeedStor         ab  Darwin boot       f2  DOS secondary
16  Hidden FAT16     63  GNU HURD or Sys   af  HFS / HFS+        fb  VMware VMFS
17  Hidden HPFS/NTF  64  Novell Netware    b7  BSDI fs           fc  VMware VMKCORE
18  AST SmartSleep   65  Novell Netware    b8  BSDI swap         fd  Linux raid auto
1b  Hidden W95 FAT3  70  DiskSecure Mult   bb  Boot Wizard hid   fe  LANstep
1c  Hidden W95 FAT3  75  PC/IX             bc  Acronis FAT32 L   ff  BBT
1e  Hidden W95 FAT1  80  Old Minix         be  Solaris boot

Partition type (type L to list all types): 82

Changed type of partition 'Linux swap / Solaris' to 'Linux swap / Solaris'.

Command (m for help): p

Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab6506b

Device     Boot  Start     End Sectors  Size Id Type
/dev/sda1         2048  206847  204800  100M 83 Linux
/dev/sda2  *    206848 2303999 2097152    1G 82 Linux swap / Solaris

You can notice the asterisk (*) on the second partition.

This asterisk means that the current partition is the bootable partition.

So in our example we need that this bootable partition is the partition 1 (sda1).

 In order to change it, let's type the "a" letter and select the partition 1.

It'll add it as the partition bootable.

But we've to remove the partition 2 as bootable by simply selecting it:

Command (m for help): a
Partition number (1,2, default 2): 1

The bootable flag on partition 1 is enabled now.

Command (m for help): p
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab6506b

Device     Boot  Start     End Sectors  Size Id Type
/dev/sda1  *      2048  206847  204800  100M 83 Linux
/dev/sda2  *    206848 2303999 2097152    1G 82 Linux swap / Solaris

Command (m for help): a
Partition number (1,2, default 2): 2

The bootable flag on partition 2 is disabled now.

Command (m for help): p
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab6506b

Device     Boot  Start     End Sectors  Size Id Type
/dev/sda1  *      2048  206847  204800  100M 83 Linux
/dev/sda2       206848 2303999 2097152    1G 82 Linux swap / Solaris

Now the sda1 partition is the only bootable partition.

The root partition

Now that we have the boot and the swap partition, it's time to create our root partition.

It's quite easy because there is nothing special here.

As we already used 100 MiB + 1 GiB = 1.1 GiB, we still have 8 - 1.1 = 6.9 GiB.

So let's take 6 GiB as our root partition and let 900 MiB free to use later (if you want):

Command (m for help): n
Partition type
   p   primary (2 primary, 0 extended, 2 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (3,4, default 3): 3
First sector (2304000-16777215, default 2304000):
Last sector, +sectors or +size{K,M,G,T,P} (2304000-16777215, default 16777215): +6G

Created a new partition 3 of type 'Linux' and of size 6 GiB.

Here we are, our 3 partitions are created, to be sure, let's print them all:

Command (m for help): p
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0ab6506b

Device     Boot   Start      End  Sectors  Size Id Type
/dev/sda1  *       2048   206847   204800  100M 83 Linux
/dev/sda2        206848  2303999  2097152    1G 82 Linux swap / Solaris
/dev/sda3       2304000 14886911 12582912    6G 83 Linux

Saving the partitions

These partitions aren't in memory yet.

It means that if you quit the fdisk tool and restart it again, these partitions won't be there.

To save it, just type the letter "w" for write:

Command (m for help): w

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

You can now quit the fdisk tool by using the "q" letter.

Setting the filesystem to partitions

In order to have a filesystem on our partitions, we have to use the mkfs.ext and the mkswap tool.

To set our partition 1 to ext2, let's do from the livecd Gentoo prompt:

livecd ~ # mkfs.ext2 /dev/sda1
mke2fs 1.42.13 (17-May-2015)
Creating filesystem with 102400 1k blocks and 25688 inodes
Filesystem UUID: 9809c750-2a6f-46f1-a101-c1060a5e4986
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729

Allocating group tables: done
Writing inode tables: done
Writing superblocks and filesystem accounting information: done

For the partition 2, we need to use the mkswap tool:

livecd ~ # mkswap /dev/sda2
Setting up swapspace version 1, size = 1024 MiB (1073737728 bytes)
no label, UUID=29c5442a-8bc9-4140-9bbe-76821790f2a1

livecd ~ # swapon /dev/sda2

livecd ~ # free

livecd src # free
              total        used        free      shared  buff/cache   available
Mem:         900636       23344       42564       64036      834728      787372
Swap:             0           0           0

livecd src # free
              total        used        free      shared  buff/cache   available
Mem:         900636       23248       42316       64036      835072      787540
Swap:       1048572           0     1048572

livecd ~ # mkfs.ext4 /dev/sda3
mke2fs 1.42.13 (17-May-2015)
Creating filesystem with 1572864 4k blocks and 393216 inodes
Filesystem UUID: 75351d27-20bd-416b-9530-0956fd95fa05
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

To verify that everything is OK, we can use the parted tool and use the print command:

livecd ~ # parted
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.

(parted) print
Model: ATA VBOX HARDDISK (scsi)
Disk /dev/sda: 8590MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system     Flags
 1      1049kB  106MB   105MB   primary  ext2            boot
 2      106MB   1180MB  1074MB  primary  linux-swap(v1)
 3      1180MB  7622MB  6442MB  primary  ext4

Everything is OK!

Mounting the boot and root partitions

After formated the partitions and set the filesystem, we are going to mount these partitions to real directories in our Gentoo.

First, we can check with the df tool that our partitions aren't mounted yet:

livecd ~ # df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             10M  4.0K   10M   1% /dev
tmpfs           440M   63M  378M  15% /
/dev/sr0        255M  255M     0 100% /mnt/cdrom
/dev/loop0      227M  227M     0 100% /mnt/livecd
tmpfs            88M  412K   88M   1% /run
shm             440M     0  440M   0% /dev/shm
cgroup_root      10M     0   10M   0% /sys/fs/cgroup
tmpfs           440M     0  440M   0% /mnt/livecd/usr/portage

We use the -h option to display sizes into readable numbers.

So our partitions aren't here.

Let's mount them:

livecd ~ # mount /dev/sda3 /mnt/gentoo/
livecd ~ # mkdir /mnt/gentoo/boot
livecd ~ # mount /dev/sda1 /mnt/gentoo/boot

Let's use again the df tool to see that this time our partitions are mounted:

livecd ~ # df -h
Filesystem      Size  Used Avail Use% Mounted on
udev             10M  4.0K   10M   1% /dev
tmpfs           440M   63M  378M  15% /
/dev/sr0        255M  255M     0 100% /mnt/cdrom
/dev/loop0      227M  227M     0 100% /mnt/livecd
tmpfs            88M  412K   88M   1% /run
shm             440M     0  440M   0% /dev/shm
cgroup_root      10M     0   10M   0% /sys/fs/cgroup
tmpfs           440M     0  440M   0% /mnt/livecd/usr/portage
/dev/sda3       5.8G   12M  5.5G   1% /mnt/gentoo
/dev/sda1        97M  1.6M   91M   2% /mnt/gentoo/boot

We can see that we have our 2 partitions sda1 (boot) and sda3 (filesystem) mounted to respectively /mnt/gentoo/boot and /mnt/gentoo directories.

To be prepared for next section, let's go into this last directory:

livecd / # cd /mnt/gentoo/

Downloading the stage tarball

This stage tarball is an archive containing basic files for the Gentoo installation.

But first we need to know which kind of computer you have, for that just type uname -m from your prompt:

livecd gentoo # uname -m

The result should be something like:

i686

So we know that our system is a i686.

First, we need to find this stage tarball on the Gentto official website:

• https://gentoo.org/downloads/mirrors/

Select the mirror of your choice and navigate through this directory (assuming your computer is a i686 one):

• releases/x86/autobuilds/current-stage3-i686

Then copy the whole link of this tarball, you should have something like this:

• ftp://ftp.gtlib.gatech.edu/pub/gentoo/releases/x86/autobuilds/current-stage3-i686/stage3-i686-20161122.tar.bz2

Come back to your Gentoo.

We assume that we are still in the /mnt/gentoo/ directory.

With the wget tool we are going to download this tarball:

livecd gentoo # wget ftp://ftp.gtlib.gatech.edu/pub/gentoo/releases/x86/autobuilds/current-stage3-i686/stage3-i686-20161122.tar.bz2

...

stage3-i686-20161122.tar.bz2. 100%[===============================================>] 226.82M  1.75MB/s    in 2m 22s
2016-11-29 10:04:02 (1.59 MB/s) - 'stage3-i686-20161122.tar.bz2.2' saved [237841553]
FINISHED --2016-11-29 10:04:02--
Total wall clock time: 2m 24s
Downloaded: 1 files, 227M in 2m 22s (1.59 MB/s)

Extracting the tarball content

Once the Stage tarball downloaded, it's time to extract its content with the tar tool:

livecd gentoo # tar xvjpf stage3-i686-20161122.tar.bz2

The xvjpf letters are options for the tar tool.

Have a look to the manual if you want to learn more.

Mounting proc, sys and dev

Before using the file system, it has to be mounted.

This is the only purpose of mounting a file system.

For example when you plug an SD card into your computer a file system is mounted for this SD card.

And when you decide to unmount it, the SD card won't appear anymore as a folder.

Well, this said, let's continue.

With the following commands we are going to mount the /proc directory (of type proc) to another folder then bind the /sys and /dev directories.

livecd mnt # mount -t proc /proc /mnt/gentoo/proc
livecd mnt # mount --rbind /sys /mnt/gentoo/sys
livecd mnt # mount --rbind /dev /mnt/gentoo/dev

We use a bind for the /dev and /sys directories because we want to be sure to be able to unmount them if needed.

So in our situtation the new /proc directory becomes /mnt/gentoo/proc whereas the /dev and /sys directories stay the same.

The rbind keyword means that we want the exact same copy of a directory, the "r" in rbind standing for recursion.

Chrooting

It's time to change the root directory from our medium (here the livecd) to the hard drive.

Currently we have created the new partitions on /mnt/gentoo.

So we are going to use this directory as the new root one.

livecd / # chroot /mnt/gentoo

You can now try to go inside the root directory, for example:

livecd / # cd /

And if you do a simple ls -la, you should see that the root directory is the new one:

livecd / # ls -la

If you wanted to come back to the old directory, you could do that, by typing exit:

livecd / # exit

Conclusion

The Gentoo basis have been seen.

That's an important step before going further.

The next stage is indeed to configure the Linux kernel, that will certainly see in a future tutorial.

Anyway, well done if you finished it and see you later!