Category: CentOS

Set hostname in CentOS 7
Hostname is a sub domain. To set hosting, edit file
```
vi /etc/hosts
```
Add
```
SERVER_IP_HERE HOSTNAME.yourdomain.com HOSTNAME
```
Example
```
72.21.51.194 server32.serverok.in server32
```
Now run
```
echo HOSTNAME.yourdomain.com > /etc/hostname
```
Example
```
echo server32.serverok.in > /etc/hostname
```
Run
```
/bin/hostname -F /etc/hostname
```
Edit file
```
vi /etc/sysconfig/network
```
Edit or add HOSTNAME entry
```
NETWORKING=yes
HOSTNAME=HOSTNAME.yourdomain.com
```
Reboot the server with
```
reboot
```
You can verify hostname with command
```
hostname
```
Related Posts

Change Server Hostname in VestaCP
Set Permanant hostname on AWS EC2 CentOS 7 server
Install SSL for Cpanel Server Hostname
December 13, 2019

CentOS 7 VestaCP Upgrade PHP to 7.x

On CentOS 7 VestaCP install PHP 5.6 by default. This is very old version of PHP. To upgrade PHP to latest version 7.x, you can install remi repo.

Install EPEL repo

yum install -y epel-release

Install yum-utils

yum install -y yum-utils

Install remi repo

rpm -ivh http://rpms.remirepo.net/enterprise/remi-release-7.rpm

Select PHP version you need

yum-config-manager --enable remi-php73

Here i selected PHP 7.3. You can select differnt PHP versions with commands like.

yum-config-manager --enable remi-php56
yum-config-manager --enable remi-php71
yum-config-manager --enable remi-php72
yum-config-manager --enable remi-php73
yum-config-manager --enable remi-php74

Make sure you only enable one PHP version. If you enabled a PHP version from remi repo, disable it with

yum-config-manager --disable remi-php56
yum-config-manager --disable remi-php70
yum-config-manager --disable remi-php71
yum-config-manager --disable remi-php72
yum-config-manager --disable remi-php73
yum-config-manager --disable remi-php74

Once you have desired version enabled, run yum upgrade

yum upgrade

Or only for PHP, run

yum upgrade php*

December 11, 2019

CentOS 7 Grub 2
To regenerate grub config on CentOS 7, run
```
grub2-mkconfig -o /boot/grub2/grub.cfg
```
If you use UEFI, run
```
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
```
OVH CentOS 7 server grub rescue prompt

Back to grub
December 2, 2019
How to reinstall packages using yum
To reinstall a package with yum, run
```
yum reinstall PKG_NAME
```
Example
```
yum reinstall kernel
```
December 2, 2019

Install Nginx on CentOS 8

To install Nginx web server on CentOS 8, create repo

vi /etc/yum.repos.d/nginx.repo

Add

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

Install nginx with dnf or yum

dnf install nginx

Open HTTP and HTTPS ports on firewall

firewall-cmd --zone=public --permanent --add-service=http
firewall-cmd --zone=public --permanent --add-service=https
firewall-cmd --zone=public --permanent --add-service=ssh
firewall-cmd --reload

November 21, 2019

Install PHP 7.4 on CentOS 7
To install PHP 7.4 on CentOS 7, first install remi repository.
```
yum install epel-release -y
rpm -ivh https://rpms.remirepo.net/enterprise/remi-release-7.rpm
```
Set PHP 7.4 as default PHP
```
yum install yum-utils
yum-config-manager --enable remi-php74
```
Install PHP with
```
yum install -y php php-bcmath php-cli php-common php-devel php-gd \
    php-imap php-intl php-json php-ldap php-lz4 php-mbstring php-mysqlnd \
    php-soap php-intl php-opcache php-xml php-pdo
```
After installing check PHP version with php -v, you will see

At the time of installation, it is PHP version 7.4.0RC3, it will change as new 7.4 release become available.

Related Posts

Install PHP 7.2 on Ubuntu
Install PHP 7.3 in CentOS 8
PHP
October 13, 2019

Install PHP 7.3 in CentOS 8

CentOS 8 comes with PHP 7.2. To install PHP 7.3, you need to enable remi repo. You can download remi-release rpm file from

http://rpms.remirepo.net

Download and install remi-release rpm

cd ; wget http://rpms.remirepo.net/enterprise/remi-release-8.rpm
dnf install remi-release-8.rpm

if you have older php version and don’t want to keep it, uninstall it with

dnf remove php-gd php-xml php-mbstring php-common php php-odbc php-mysqlnd php-json php-process php-cli php-fpm php-intl php-bcmath php-soap php-pdo

Install PHP 7.3

dnf install php73

Set it as default PHP version

update-alternatives --install /usr/bin/php php /usr/bin/php73 1

Install PHP modules

dnf install -y php73-php php73-php-gd php73-php-fpm php73-php-pdo php73-php-xml php73-php-json php73-php-imap php73-php-intl php73-php-json php73-php-soap php73-php-bcmath php73-php-xmlrpc php73-php-mysqlnd php73-php-mbstring php73-php-zip

Install php-fpm package

dnf install php73-php-fpm

set php-fpm to start on boot

systemctl enable php73-php-fpm

Start php-fpm

systemctl start php73-php-fpm

Restart Apache

systemctl restart httpd

PHP 7.3 php.ini located at

/etc/opt/remi/php73/php.ini

Module directory for PHP 7.3 at

/opt/remi/php73/root/usr/lib64/php/modules/

Related Posts

CentOS 8

PHP

October 6, 2019

Install Apache, MySQL, PHP (LAMP) Stack on CentOS 8

First disable SELinux by editing file

vi /etc/selinux/config

Find

SELINUX=enforcing

Replace with

SELINUX=disabled

Now restart the server.

reboot

Verify SELinux is disabled by running “sestatus” command. It should show disabled.

CentOS 8 sestatus

Install basic tools

Lets start by installing some basic tools like whois, curl, git etc..

dnf -y install wget curl telnet bind-utils net-tools git

Configure Firewall

On CentOS 8 by default only port 22 (SSH) is open to public. To run a web server, you need to open ports 80 and 443.

Run following command to open ports in firewall

firewall-cmd --zone=public --permanent --add-service=http
firewall-cmd --zone=public --permanent --add-service=https
firewall-cmd --zone=public --permanent --add-service=ssh
firewall-cmd --zone=public --permanent --add-port=25/tcp
firewall-cmd --reload

Install Apache

To install Apache, run

dnf -y install httpd

Enable Apache to start on boot by running

systemctl start httpd

Verify Apache is running with command

netstat -lntp | grep 80

If Apache is running, you will see something like

CentOS 8 apache netstat

If all works good, you should be able to access your web server by opening your server IP in a web browser.

CentOS 8 Apache Default page

Install PHP

CentOS 8 comes with PHP 7.2

To install PHP, run

dnf -y install php php-cli php-xml php-json php-intl php-odbc php-pdo php-soap php-mysqlnd php-process php-bcmath php-gd php-mbstring

Install php-fpm

dnf -y install php-fpm

Enable php-fpm start on boot

systemctl enable php-fpm

Start php-fpm with

systemctl start php-fpm

php-fpm pool config files are located in folder /etc/php-fpm.d. php-fpm listens on socket at /run/php-fpm/www.sock

php-fpm package comes with Apache config file, it get placed on /etc/httpd/conf.d/php.conf. Restart apache to get php-fpm activated.

systemctl restart httpd

Now create a file

vi /var/www/html/1.php

with content

You should be able to access phpinfo page on URL

http://YOUR-SERVER-IP/1.php

php.ini file located in /etc/php.ini, you need to restart php-fpm service if you edit this file.

Install MySQL

We will install MariaDB, it is an open source drop in replacement for MySQL, created by creator of MySQL. To install MariaDB, run

dnf install mariadb-server

Enable MariaDB to start on boot

systemctl enable mariadb

Start MariaDB

systemctl start mariadb

CentOS 8 come with MariaDB 10.3. By default there is no root PW set, So you can connect to MySQL with command "mysql".

CentOS 8 MariaDB

To create a database, use

create database DB_NAME_HERE;

To create a user, run

grant all on DB_NAME_HERE.* to 'USER_NAME'@'localhost' identified by 'PASSWORD_HERE';

Now you have Apache, PHP, MySQL ready to use. Upload your web application to /var/www/html folder using SFTP.

See CentOS 8

October 5, 2019

Creating CentOS 8 Virtual Machine with Vagrant
Create a directory for Vagrant project
```
mkdir -p ~/vagrant/centos8
cd ~/vagrant/centos8
vagrant init generic/centos8
```
This will create a file with name “Vagrantfile” on current folder. To start the CentOS 8 VM, run
```
vagrant up
```
To SSH into CentOS 8 virtual machine
```
vagrant ssh
```
To stop a VM, run
```
vagrant halt
```
See Vagrant
September 30, 2019
CentOS 8 disable Activate the web console message
When login to CentOS 8 using SSH, you get a message asking you to enable web console.
```
Activate the web console with: systemctl enable --now cockpit.socket
```
You can uninstall cockpit with command
```
yum remove cockpit*
```
If you just need to disable the message, delete the file
```
rm -f /etc/motd.d/cockpit
```
This is actually a symlink to file /run/cockpit/motd

See CentOS 8
September 29, 2019
dnf – Package manager for CentOS/RHEL 8
dnf is package manager for RHEL/CentOS 8. This is improved version of yum.

To search for a package, use
```
dnf search PACKAGE_NAME
```
To install a package, use
```
dnf install PACKAGE_NAME
```
September 28, 2019
Install CentOS 8 from Net boot ISO
CentOS 8 provide 2 type of ISO. One that ends with boot.iso, this is 534 MB. This only include essential files to get you started with installation. This installation method require internet connection as files needed to be downloaded from internet. Other ISO file is full install media, that is 6.6 GB in size. To install from boot.iso, download it from

http://isoredirect.centos.org/centos/8/isos/x86_64/

This page will list morrors near to you.

Click on any of the morror from link, on next page, you will see ISO files. Download CentOS-8-x86_64-xxxx-boot.iso

Write this ISO file into a USB drive or DVD, then boot your computer with it. You will see following screen.

Select first or second option. 2nd option test install media for any errors. If you use USB drive, you can just select option 1 as there is less chance of media corruption compared to DVD drives.

Select language, click continue.

On this screen, you need to make several choices.

Installation Destination

Select the hard disk where you need CentOS 8 installed.

If you have an empty disk, all you need to do is click “Done”.

If your disk have existing partitions, you may need to delete it before insalling CentOS 8. If you have any data on this hard disk, always take a backup before you installing new OS.

Network & Host Name

You need to configure your network. Most of the time all you need to do is click on ON/OFF toggle on right side of the network interface.

If you have DHCP on your network, you will see IP address assigned to your computer. If not, you need to manually configure networking. It is important as you will need internet to do CentOS 8 install using boot ISO file. Click Done to go back to previous screen.

Installation Source

On this page, you need to enter a CentOS mirror. You can use following URL
```
http://mirror.centos.org/centos/8/BaseOS/x86_64/os/
```
It is better to use a CentOS mirror near to you. This will make file downloads faster. In my case, i used
```
http://centos.mirrors.estointernet.in/8.0.1905/BaseOS/x86_64/os/
```
There is option to select mirror near you on this screen. But for some reason, this option did not work for me.

Software Slection

On this screen, you need to select software to install.

You can select if you need to install GUI or just minimal CentOS install. I selected minimal install as everything else can be installed later as needed.

Click “Done”, will take you to previous screen. Now you will see “Begin Installation” button enabled. Click on it to continue installation.

On next screen, you get option to set password. Set password for user root. You can also create a new user if required.

Installation take 15 to 30 minutes depending on your download speed. Once installation completed, you will be asked to reboot.

CentOS 8 use Kernel 4.18
```
[root@192 ~]# hostnamectl 
   Static hostname: localhost.localdomain
Transient hostname: 192.168.1.5
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 7ad955dffb89464a96918974be28795b
           Boot ID: 77cd4c012cbe4b6f9c33ab7dae5ecc33
    Virtualization: oracle
  Operating System: CentOS Linux 8 (Core)
       CPE OS Name: cpe:/o:centos:centos:8
            Kernel: Linux 4.18.0-80.7.1.el8_0.x86_64
      Architecture: x86-64
[root@192 ~]# 
```
You can use both yum and dnf for installing software.
September 27, 2019