CentOS versions download: here
"The CentOS Linux distribution is a stable, predictable, manageable and reproducible platform derived from the sources of Red Hat Enterprise Linux (RHEL). Since March 2004, CentOS Linux has been a community-supported distribution derived from sources freely provided to the public by Red Hat. As such, CentOS Linux aims to be functionally compatible with RHEL.
The CentOS Project is a community-driven free software effort focused around the goal of providing a rich base platform for open source communities to build upon. We will provide a development framework for cloud providers, the hosting community, and scientific data processing, as a few examples. We work with several ‘upstream’ communities to help them layer and distribute their software more effectively on a platform they can rely on.
The CentOS Project is modelled on the structure of the Apache Foundation, with a governing board that oversees various semi-autonomous Special Interest Groups or ‘SIGs’. These groups are focused on providing various enhancements, addons, or replacements for core CentOS Linux functionality. A few notable examples of SIGs are:
Core - Building and releasing the core CentOS Linux platform. Xen4CentOS - Providing Xen4 support for CentOS 6 CentOS Design - Improving the user experience with high quality artwork."*
*find more here: https://www.centos.org/about/
|CentOS Version||Release Date|
CentOS 7 is fully based on RedHat the detail documentation, examples and system administration guides are located here:CentOS 7 full documention
Detailed instructions on getting CentOS 7 installation and basic set up for starting on.
On the next step you can choose your system installation software. On this step CentOS offers a lot of Server and Desktop platform environments that you choose from, but, if you want a high degree of customization, especially if you are going to use CentOS 7 to run as a server platform, then I suggest you select Minimal Install with Compatibility Libraries as Add-ons, which will install a minimal basic system software and later you can add other packages as your needs require using:
[ yum groupinstall “Name of installed package” ] command.
NOTE: For those users, who have hard-disks more than 2TB in size, the installer automatically will convert partition table to GPT, but if you wish to use GPT table on smaller disks than 2TB, then you should use the argument inst.gpt to the installer boot command line in order to change the default behavior.
IMPORTANT: If you do not have an IPv6 internet connection, then set IPv6 from auto to ignore on the IPv6 tab, otherwise you won't be able to reach the internet from this server on IPv4 as CentOS seems to ignore the correct IPv4 setup then and uses IPv6 instead which fails.
Congratulation! You have now installed last version of CentOS on your bare new machine. Remove any installation media and reboot your computer so you can login to your new minimal CentOS 7 environment and perform other system tasks, such as update you system and install other useful software needed to run day to day tasks.
First Login on CentOS
Login as root user to the server so we can do some final installation steps.
The first one is to install all available updates with yum.
confirm with "y" to proceed with the installation of the updates.
I will install two command line editors to be able to edit configuration files on the shell:
yum install nano vim
CentOS 7.2 minimal don't come pre-installed with the ifconfig command we will install it as follows:
yum install net-tools
If you want to change or see the network configuration file, just edit the file
It will be like this when you configured a static IP address:
TYPE="Ethernet" BOOTPROTO="none" DEFROUTE="yes" IPV4_FAILURE_FATAL="no" IPV6INIT="no" IPV6_AUTOCONF="yes" IPV6_DEFROUTE="yes" IPV6_PEERDNS="yes" IPV6_PEERROUTES="yes" IPV6_FAILURE_FATAL="no" NAME="ens33" UUID="eb1ba0ce-af9f-4953-a6a7-3d05a15c8d4f" DEVICE="ens33" ONBOOT="yes" IPADDR="192.168.1.100" PREFIX="24" GATEWAY="192.168.1.1" DNS1="192.168.1.1" DNS2="184.108.40.206" DNS3="220.127.116.11" Or like this when you use DHCP: TYPE="Ethernet" BOOTPROTO="dhcp" DEFROUTE="yes" IPV4_FAILURE_FATAL="no" IPV6INIT="yes" IPV6_AUTOCONF="yes" IPV6_DEFROUTE="yes" IPV6_FAILURE_FATAL="no" NAME="ens33" UUID="eb1ba0ce-af9f-4953-a6a7-3d05a15c8d4f" DEVICE="ens33" ONBOOT="yes" HWADDR="00:50:56:15:23:79" PEERDNS="yes" PEERROUTES="yes" IPV6_PEERDNS="yes" IPV6_PEERROUTES="yes" IPV6_PRIVACY="no"
Change the values if required.
Note: The above DEVICE name may vary so please check the equivalent file in the directory /etc/sysconfig/network-scripts.
Adjust the file /etc/hosts as follows:
Make the values like this:
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 192.168.1.100 server1.example.com server1 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
Congratulations! Now we have basic minimal CentOS 7 server setup
Now you may prefer to use GUI instead, here is a variety of flavor you could choose from:
Install GNOME Desktop Environment by entering.
# yum -y groups install "GNOME Desktop"
To start the GUI enter after finishing installation:
How to use GNOME Shell?
The default GNOME Desktop of CentOS 7 starts with classic mode but if you'd like to use GNOME Shell, set like follows:
Option A: If you start GNOME with startx, set like follows.
# echo "exec gnome-session" >> ~/.xinitrc # startx
Option B: set the system graphical login systemctl set-default graphical.target and reboot the system. After system starts
GNOME shell starts like follows:
Install KDE Desktop Environment by entering
# yum -y groups install "KDE Plasma Workspaces"
Input a command like below after finishing installation:
# echo "exec startkde" >> ~/.xinitrc # startx
KDE Desktop Environment starts like follows:
Installing MATE Desktop Environment:
Install MATE Desktop Environment by entering.
# yum --enablerepo=epel -y groups install "MATE Desktop"
Input a command like below after finishing installation:
# echo "exec /usr/bin/mate-session" >> ~/.xinitrc # startx
MATE Desktop Environment starts.
Installing Xfce Desktop Environment:
Install Xfce Desktop Environment by entering.
# yum --enablerepo=epel -y groups install "Xfce"
Input a command like below after finishing installation:
# echo "exec /usr/bin/xfce4-session" >> ~/.xinitrc # startx
Xfce Desktop Environment starts.
OTHER WAY TO DO IT:
Rather than make use of the hacking of a startx command into a .xinitrc file, it's probably better to tell Systemd that you want to boot into a graphical GUI vs. the terminal.
To accomplish this simply do the following:
$ sudo yum groupinstall "GNOME Desktop" $ ln -sf /lib/systemd/system/runlevel5.target /etc/systemd/system/default.target
Then simply reboot.
The last bit will associate the runlevel 5 target as your default with respect to Systemd.
Doing it with Systemd
You can also use Systemd to accomplish this. This is arguably the better method since you're managing the state of the system directly through Systemd and its CLIs.
You can see what your current default target is:
$ sudo systemctl get-default multi-user.target
And then change it to graphical:
$ sudo systemctl set-default graphical.target
In Systemd the targets runlevel5.target and graphical.target are identical. So too are runlevel2.target and multi-user.target.
Runlevel Target Units Description 0 runlevel0.target, poweroff.target Shut down and power off the system. 1 runlevel1.target, rescue.target Set up a rescue shell. 2 runlevel2.target, multi-user.target Set up a non-graphical multi-user system. 3 runlevel3.target, multi-user.target Set up a non-graphical multi-user system. 4 runlevel4.target, multi-user.target Set up a non-graphical multi-user system. 5 runlevel5.target, graphical.target Set up a graphical multi-user system. 6 runlevel6.target, reboot.target Shut down and reboot the system.
RHEL / CentOS Linux Install Core Development Tools Automake, Gcc (C/C++), Perl, Python & Debuggers
Q. How do I install all developer tools such as GNU GCC C/C++ compilers, make and others, after installing CentOS or RHEL or Fedora Linux from a shell prompt?
You need to install ‘Development Tools’ group on RHEL/CentOS/Fedora/Scientific/Red Hat Enterprise Linux. These tools include core development tools such as automake, gcc, perl, python, and debuggers which is required to compile software and build new rpms:
Open the terminal or login over ssh session and type the following command as root user:
# yum groupinstall 'Development Tools'
Sample outputs that follows:
Loading "fastestmirror" plugin Loading mirror speeds from cached hostfile * base: mirror.steadfast.net * updates: dist1.800hosting.com * addons: centos.mirrors.tds.net * extras: dist1.800hosting.com Setting up Group Process Loading mirror speeds from cached hostfile * base: mirror.steadfast.net * updates: dist1.800hosting.com * addons: centos.mirrors.tds.net * extras: dist1.800hosting.com Package make - 1:3.81-3.el5.i386 already installed and latest version Package gettext - 0.14.6-4.el5.i386 already installed and latest version Package binutils - 18.104.22.168.6-6.el5.i386 already installed and latest version Resolving Dependencies --> Running transaction check ---> Package automake.noarch 0:1.9.6-2.1 set to be updated ---> Package frysk.i686 0:0.0.1.2008.03.19.rh1-1.el5 set to be updated --> Processing Dependency: libgcj.so.7rh for package: frysk --> Processing Dependency: glib-java >= 0.2.6 for package: frysk ---> Package autoconf.noarch 0:2.59-12 set to be updated --> Processing Dependency: imake for package: autoconf ---> Package rcs.i386 0:5.7-30.1 set to be updated ---> Package strace.i386 0:4.5.16-1.el5.1 set to be updated ---> Package redhat-rpm-config.noarch 0:8.0.45-24.el5 set to be updated ---> Package elfutils.i386 0:0.125-3.el5 set to be updated --> Processing Dependency: libdw.so.1 for package: elfutils ........... .... .. Transaction Summary ============================================================================= Install 105 Package(s) Update 0 Package(s) Remove 0 Package(s) Total download size: 127 M Is this ok [y/N]: y Downloading Packages: (1/105): python-numeric-2 100% |=========================| 751 kB 00:12 (2/105): xorg-x11-fonts-b 100% |=========================| 3.7 MB 01:03 (3/105): pfmon-3.2-0.0609 100% |=========================| 656 kB 00:10 (4/105): automake14-1.4p6 100% |=========================| 205 kB 00:03 (5/105): libtool-1.5.22-6 100% |=========================| 680 kB 00:11 (6/105): systemtap-0.6.2- 100% |=========================| 1.3 MB
Now you can compile and use any application on your system.
To display Gnu gcc/c/c++ compiler version type:
$ gcc --version
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-4) Copyright (C) 2010 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
How do I list all currently running services in Fedora / RHEL / CentOS Linux server?
There are various ways and tools to find and list all running services under Fedora / RHEL / CentOS Linux systems.
service command – list running services
The syntax is as follows for CentOS/RHEL 6.x and older (pre systemd):
service --status-all service --status-all | more service --status-all | grep ntpd service --status-all | less
Print the status of any service. To print the status of apache (httpd) service:
service httpd status
List all known services (configured via SysV)
List service and their open ports
Turn on / off service
ntsysv chkconfig service off chkconfig service on chkconfig httpd off chkconfig ntpd on
ntsysv is a simple interface for configuring runlevel services which are also configurable through chkconfig. By default, it configures the current runlevel. Just type ntsysv and select service you want to run.
A note about RHEL/CentOS 7.x with systemd
If you are using systemd based distro such as Fedora Linux v22/23/24 or RHEL/CentOS Linux 7.x+. Try the following command to list running services using the systemctl command. It control the systemd system and service manager.
To list systemd services on CentOS/RHEL 7.x+ use
The syntax is:
systemctl systemctl | more systemctl | grep httpd systemctl list-units --type service systemctl list-units --type mount
To list all services:
above image shows List all units installed on the CentOS /RHEL 7 systemd based system, along with their current states
To view processes associated with a particular service (cgroup), you can use the systemd-cgtop command. Like the top command, systemd-cgtop lists running processes based on their service:
To list SysV services only on CentOS/RHEL 7.x+ use (does not include native systemd services)
FIREWALL HOW TO: