Centos 7 dvd

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Introduction

CentOS
is one of the most reliable Linux distributions. The abbreviation in the name stands for Community ENTerprise Operating System. CentOS based
on a commercial distribution of Red Hat Enterprise Linux (RHEL) and uses Yum to download and install updates from the repository.

CentOS 7 system requirements

Also, all specifications for all versions of the operating system can be viewed on the official website
.

CentOS 7 ISO Image Destinations

CentOS-7-x86_64-DVD

This ISO image is standard and contains all the packages that you can select when installing the system. Start your acquaintance with CentOS with it

NetInstall

The NetInstall image is intended for installing a system over a network or for recovering a damaged system.
You will be given the choice of the location from which the packages will be installed. This is very convenient if you have a local repository with the required number of packages.

Everything

The Everything ISO image contains the most complete set of operating system packages. The size of this image is about 8 GB.

LiveGNOME and LiveKDE

These two images are a CenOS 7 LiveCD. The difference between them is only in the KDE or GNOME graphical environment. You can test the system without installing it on your hard drive.

Minimal

The minimum ISO image is nothing superfluous and it will only be enough for the basic functionality of the system with the most minimal set of packages.
Everything else you will have to install yourself from the repositories. But nothing superfluous and unnecessary 🙂

Download CentOS 7

Creating a bootable CentOS7 USB disk

I think the most successful program for burning ISO images is Rufus 3.11
.
It is very easy to use and intuitive. If the link to download the program did not work, then you will always find the latest version here
.

Let’s start installing CentOS 7

When we boot from the image, select the item Install CentOS 7
and initialize the installation of the system

Select the system installation language and press

Now in order DATE & TIME

Specify the region, city, time and date. Function Network Time
allows you to choose synchronization with NTP servers. Nothing complicated, however, like the whole installation process. Press the button to return to the previous menu

In Section KEYBOARD
through the button we open the list of languages, look for the required language and add it. As the desired language was added, go to the previous menu.
Section LANGUAGE SUPPORT
there’s nothing tricky either 🙂

Go to the tab IPv4 Settings and specify the required parameters

Now we need to select the CentOS installation location INSTALLATION DESTINATION
select a disk and go to the previous menu.

To manually partition a disk, you need to know which partition is for what. When creating partitions, do not forget to select the type LVM
(except the boot-xfs partition)!

• /
  root section. Under it, it is worth allocating at least 20-30 GB, since system files are stored in it.
• /home
  this is the user directory section. This section stores the user’s desktop, documents, images, etc. If this is not a desktop machine, but a server, then
  Allocate no more than 10 GB to the partition.
• /swap
  this is the swap file. It is calculated something like this: 1 GB of RAM = 2 GB
• /boot
  section for loading the system, from the master’s shoulder we will throw him 1 GB: D.
• /var
  a very important section in terms of information security, since all logs are written to it, SQL databases and downloaded RPM packages are stored. All that remains, we allocate under this section.

V SOFTWARE SELECTION
we can check the required packages, but for now I’ll leave everything as it is by default.

Starting the installation of CentOS 7

During installation, we will need to create a user and set a password for root.

Upon completion of the installation of the system, we go into reboot

With default settings, our server is accessible via SSH. That’s actually the whole installation 🙂

Setting up CentOS 7

Network Manager Service

Network Manager is needed to automatically connect to the network. This is a very necessary service for a home computer, but we do not need it on the server, as we clearly know
how we need to configure the network connection.

 systemctl stop NetworkManager
systemctl disable NetworkManager
systemctl restart network 

Setting up a CentOS 7 network

Configuring the network by editing the config /etc/sysconfig/network-scripts/ifcfg-eth0
. Sample file below

 DEVICE=eth0
BOOTPROTO=none
ONBOOT=
IPADDR=192.168.0.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1 

We also need to specify the server name in the files /etc/sysconfig/network
and /etc/hostname

 vi /etc/sysconfig/network 

=yes
=hostname 

 vi /etc/hostname 

 hostname.itlocate.ru 

Configure DNS in file DNS in /etc/resolv.conf

 vi /etc/resolv.conf 

 nameserver 192.168.1.10
nameserver 192.168.1.11 

After all this, we need to restart the network interface service

 systemctl restart network 

Download files over the network

Install wget package

 yum update #if you haven't already :)
yum -y install wget 

Installing and configuring NTPD

Ntpd (Network Time Protocol daemon) is a service for synchronizing time with a server.

 yum -y install ntp
timedatectl set-timezone Europe/Moscow #set the timezone 

Now we need to register these same servers. Open the ntp.conf file

 vi /etc/ntp.conf 

 server ntp1.server1.ru iburst
server ntp1.server1.ru iburst
server ntp3.server2.ru iburst
server ntp4.server3.ru iburst 

But, having installed the NTPD service, now you can synchronize the time from our server, in order to disable this function, execute the following command:

 restrict default ignore 

If someone still needs to receive time from our server, then you can add it to the exceptions

 restrict 192.168.0.133 noquery notrap 

In the local network, you can register as follows

 restrict 192.168.0.123 mask 255.255.255.0 nomodify notrap 

The firewall can cut synchronization, so let’s add the NTPD service to the exceptions

 firewall-cmd --add-service=ntp --permanent
firewall-cmd --reload 

Start the service and add it to startup

 systemctl start ntpd
systemctl enable ntpd 

You can test as follows

 ntpq -p # server list
date -R # print the current date and time