DokuWiki » Infrastructure » Operating System » CentOS 9

h1. Install

I want to say first that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take.

h2. 1 Requirements

To install such a system you will need the following:

* Download the boot.iso 9.x from a mirror next to you

https://download.rockylinux.org/pub/rocky/9/isos/x86_64/Rocky-9.4-x86_64-boot.iso

* a fast Internet connection.

* bootable USB-drive (create e.g. with Fedora Media Writer or similar)

h2. 2 Preliminary Note

In this tutorial I use the hostname @server1.example.com@ with the IP address @192.168.0.100@ and the gateway @192.168.0.1@. These settings might differ for you, so you have to replace them where appropriate.

_Screenshots are taken from an CentOS 7.x installation. Remove this remark as soon as pictures are replaced with CentOS 9.x screenshots. Content is basically equivalent._

h2. 3 Configure The Base System

Boot from your first USB drive. 

As it can take a long time to test the installation media we skip this test here and press @<ENTER>@ at the boot prompt: 

!{width 500}centos7_inst01.png!

Choose your language next: 

!{width 500}centos7_inst02.png!

CentOS 9 uses a central point of configuration.

We will enter each section and return until all our settings are done.

!{width 500}centos7_inst03.png!

h3. Network & Hostname

Set the hostname manually, e.g. @server1.example.com@

Enable the network interfaces and @configure@ each of them

!{width 500}centos7_inst04.png!

On to the configure network. The default setting here is to configure the network interfaces with DHCP, but we are installing a server, so static IP addresses are not a bad idea… Click on the Edit button after selecting the interface. 

!{width 500}centos7_inst07.png!

In the window that pops up uncheck Dynamic IP configuration (DHCP) and Enable IPv6 support and give your network card a static IP address (in this tutorial I'm using the IP address 192.168.0.100 for demonstration purposes) and a suitable netmask (e.g. 255.255.255.0; if you are not sure about the right values, http://www.subnetmask.info might help you) also enter a gateway (e.g. 192.168.0.1) and up to two DNS servers (e.g. 8.8.8.8 and 145.253.2.75). By default all interfaces are not connected automatically, in most cases you want to change this. 

!{width 500}centos7_inst06.png!

h3. Date & Time

Choose your time zone:

Check Date and Time, as many services are very dependant on the timestamp you should set an approprate time-server or even better a time-server-pool. If you have internet access and are based in germany you might want to use following public NTP-server-pool.

<pre><code class="bash">

0.de.pool.ntp.org

1.de.pool.ntp.org

2.de.pool.ntp.org

3.de.pool.ntp.org

</code></pre>

check www.ntp.org for details. If you don't have access to a public NTP-server ask your admin for a local NTP-server. 

!{width 500}centos7_inst08.png!

h3. Keyboard

Select your keyboard layout: 

!{width 500}centos7_inst09.png!

h3. Installation Source

you may point to a local source or a web-based-server

!{width 500}centos7_inst10.png!

h3. Software Selection

for this example we go for a standard @GNOME-Desktop@

But you may want to consider a more appropriate selection for your system.

!{width 500}centos7_inst11.png!

h3. Installation Destination NON-RAID

Typically you will choose @Local Standard Disks@ here 

!{width 500}centos7_inst12.png!

Now we must select a partitioning scheme for our installation. Usually you will want to configure the layout on your own.

!{width 500}centos7_inst13.png!

This will result in a small @/boot@ and a large @/@ partition as well as a swap partition. Of course, you're free to partition your hard drive however you like it.

|_. type                  |_. logical volume name |_. mount point |_. size |

|_. small database server | lv_swap             | swap        |   512|

|_.                       | lv_home             | \home       |  1024|

|_.                       | lv_var_log          | \var\log    |  1024|

|_.                       | lv_var              | \var        |  8192|

|_.                       | lv_root             | \           |  8192|

Click on @Done@ to continue: 

!{width 500}centos7_inst14.png!

* The hard drive is going to be formatted

* After the drive being formatted the partitioning layout needs to be written to disk

h3. Installation Destination RAID1

taken from: https://www.tuxfixer.com/centos-7-installation-with-lvm-raid-1-mirroring/

Select both disks from the available devices and choose “I will configure partitioning” option:

!{width 500}centos_7_inst_raid1_01.png!

You will be redirected to MANUAL PARTITIONING screen.

First create boot partition with the following parameters:

* mount point: /boot

* size: 1024MB

* device type: RAID

* RAID level: RAID 1 (Mirroring)

* file system: xfs

!{width 500}centos_7_inst_raid1_02.png!

Now let’s create swap and root partitions. We will create them inside the volume group called centos which will be placed on top of RAID 1.

Let’s start from swap creation with the following parameters:

* mount point: swap

* device type: LVM

* files system: swap

During swap creation choose Device Type: LVM and click on Modify button in Volume Group area:

!{width 500}centos_7_inst_raid1_03.png!

Now we need to create centos Volume Group on the top of RAID 1 (using automatic size policy):

!{width 500}centos_7_inst_raid1_04.png!

swap partition is now created as a Logical Volume named centos-swap:

!{width 500}centos_7_inst_raid1_05.png!

Now create root partition with the following parameters:

* mount point: /

* device type: LVM (use previously created centos VG on top of RAID 1)

* files system: xfs

!{width 500}centos_7_inst_raid1_06.png!

root partition is now created as a Logical Volume named centos-root.

Click on Done button, accept all the changes made to the partitions on SUMMARY OF CHANGES screen, return to INSTALLATION SUMMARY screen and continue installation as usual.

h2. 4 Install The Base System

!{width 500}centos7_inst15.png!

!{width 500}centos7_inst16.png!

h3. Set ROOT password

Give @root@ a password: 

!{width 500}centos7_inst17.png!

h3. Create Additional User

you should always have a user even in a server environment. Use your root access only when necessary to prevent unintended changes to the system. 

!{width 500}centos7_inst18.png!

!{width 500}centos7_inst19.png!

!{width 500}centos7_inst20.png!

h2. Initial Setup

!{width 500}centos7_inst21.png!

h3. Licence Information

!{width 500}centos7_inst22.png!

!{width 500}centos7_inst23.png!

If you enable kdump, you may want to stay with the preset defaults. 

Let's go Finish

!{width 500}centos7_inst24.png!

Finally, the installation is complete, and you can remove your CD or DVD from the computer and reboot it:

Welcome to your GNOME-Desktop-Environment.

After finishing our installation let's login the very first time.

!{width 500}centos7_inst25.png!

We change the screen to a text console via @CTRL-ALT-F2@

Please provide your username @root@. Do you still remember the password you thought of a few minutes ago? 

!{width 500}centos7_inst26.png!

get all the latest updates via @yum update@

!{width 500}centos7_inst27.png!

The installation begins. This will take a few minutes:

h2. 5 Post Installation Steps

h3. check RAID1 status

if XFS on top of LVM on top of RAID1 is used during install following outputs should appear

<pre><code class="shell">

pvs

</code></pre>

<pre>

  PV         VG        Fmt  Attr PSize   PFree

  /dev/md127 rl_hostXX lvm2 a--  143.14g    0 

</pre>

<pre><code class="shell">

vgs

</code></pre>

<pre>

  VG        #PV #LV #SN Attr   VSize   VFree

  rl_hostXX   1   3   0 wz--n- 143.14g    0 

</pre>

<pre><code class="shell">

lvs

</code></pre>

<pre>

  LV   VG        Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert

  home rl_hostXX -wi-ao----  18.62g                                                    

  root rl_hostXX -wi-ao---- <93.13g                                                    

  swap rl_hostXX -wi-ao----  31.39g               

</pre>

<pre><code class="shell">

cat /proc/mdstat

</code></pre>

<pre>

Personalities : [raid1] 

md127 : active raid1 nvme3n1p3[0] nvme2n1p2[1]

      150096896 blocks super 1.2 [2/2] [UU]

      bitmap: 1/2 pages [4KB], 65536KB chunk

unused devices: <none>

</pre>

h3. Install additional packages

With @minimal Desktop@ the most important packages are already installed. If you are curious about installed and available package-groups use

<pre><code class="bash">

dnf grouplist

</code></pre>

and install additional groups via

<pre><code class="bash">

dnf groupinstall "xxx"

</code></pre>