How to Change default runlevel in CentOS 7 / RHEL 7

Change default runlevelIn CentOS 7 and RHEL 7, the systemd process replaces the init process for starting services at boot time and also for changing the runlevels. It uses “targets” instead of run-levels and relies on systemctl command to change runlevel or to change the target.

The systemd provides much more control than the init process does while still supporting existing init scripts.

Take note that in RHEL 7 and CentOS 7, any edits of /etc/inittab file will not take effect.

The following articles describe how to change default runlevel in CentOS 7 / RHEL 7.

1. How to determine the state that the system currently configured to boot to :

# systemctl get-default

Example 1 :
If the system running on Non-GUI Mode, “systemctl get-default” command will return “multi-user.target” :

Method 1 :

[root@centos72 ~]# systemctl get-default
multi-user.target

Method 2 :

[root@centos72 ~]# ls -al /etc/systemd/system/default.target
lrwxrwxrwx. 1 root root 37 May 30  2015 default.target -> /lib/systemd/system/multi-user.target

Example 2 :
If the system running on GUI Mode, “systemctl get-default” command will return “graphical.target” :
Method 1 :

[root@centos72-gui ~]# systemctl get-default
graphical.target

Method 2 :

[root@centos72-gui ~]# ls -al /etc/systemd/system/default.target
lrwxrwxrwx. 1 root root 36 Jun  5  2015 /etc/systemd/system/default.target -> /lib/systemd/system/graphical.target

However, you can still use the runlevel command as it was left intact for backward compatibility:

[root@centos72 ~]# runlevel
N 3
[root@centos72-gui ~]# runlevel
N 5

In case you are required to change from your CentOS 7 from Non-GUI (text-based) mode to GNOME Desktop mode, you have to ensure the following group of packages has been installed properly :

a) Server with GUI (This is for server)
b) GNOME Desktop
c) Graphical Administration Tools

2. How to Install Gnome GUI in CentOS 7 :

# yum groupinstall "GNOME Desktop" "Graphical Administration Tools" "Server with GUI"

3. How to list all currently loaded and available targets :

# systemctl list-units -t target
UNIT                 LOAD   ACTIVE SUB    DESCRIPTION
basic.target         loaded active active Basic System
cryptsetup.target    loaded active active Encrypted Volumes
getty.target         loaded active active Login Prompts
graphical.target     loaded active active Graphical Interface
local-fs-pre.target  loaded active active Local File Systems (Pre)
local-fs.target      loaded active active Local File Systems
multi-user.target    loaded active active Multi-User System
network.target       loaded active active Network
paths.target         loaded active active Paths
remote-fs-pre.target loaded active active Remote File Systems (Pre)
remote-fs.target     loaded active active Remote File Systems
slices.target        loaded active active Slices
sockets.target       loaded active active Sockets
swap.target          loaded active active Swap
sysinit.target       loaded active active System Initialization
timers.target        loaded active active Timers

In below example, the following target are required to be laoded :

graphical.target     loaded active active Graphical Interface
multi-user.target    loaded active active Multi-User System

How to Change default runlevel

4. How to Change default runlevel from Non-GUI (text-based) mode to GNOME Desktop in CentOS 7 / RHEL 7

# systemctl set-default multi-user.target

5. How to Change default runlevel from GNOME Desktop to Non-GUI (text-based) mode in CentOS 7 / RHEL 7

# systemctl set-default graphical.target

Resource :
https://access.redhat.com/articles/754933

How to Download CentOS 7 ISO

Download CentOS 7 ISO

In July 2014, a welcome version of CentOS 7 which tagged as 1406 (CentOS 7.0) officially released. As of end-March 2015, the second CentOS 7 release tagged as 1503 (CentOS 7.1) is available for download and CentOS 7.2  that was tagged as 1511 was released on 14 December 2015.

As of end-March 2015, the second CentOS 7 release tagged as 1503 (CentOS 7.1) is available for download and CentOS 7.2  that was tagged as 1511 was released on 14 December 2015.

The latest release supersedes all previously released content for CentOS 7, therefore it is recommended for all users to upgrade their CentOS machines. This article will list the URL to download CentOS 7 ISO images.

CentOS is an Enterprise-class Linux Distribution derived from sources freely provided to the public by Red Hat.For those who do not want to perform

For those who do not want to perform fresh install of CentOS 7 on the existing machine, you also can get CentOS 7 running by following the upgrade path from CentOS-6 to CentOS-7.

But this path is only supported from the latest version of CentOS-6 (being 6.7 at the time of writing) to the latest version of CentOS-7.

Mirror list to download CentOS 7 ISO images available :

a) Download centos 7 64 bit (4.0GB)
b) Download centos 7 64 bit Everything (7.1GB)
c) Download centos 7 netinstall
d) Download centos 7 live cd

The following alternate mirrors should also have the ISO images available.

Before you download, you also can read the Major Changes for CentOS 7.0 (1406) :
As with every first major release most of the packages have changed and have been updated to more recent versions. It would exceed the scope of this document to list them all. Most notable changes are:

  • Kernel updated to 3.10.0
  • Support for Linux Containers
  • Open VMware Tools and 3D graphics drivers out of the box
  • OpenJDK-7 as default JDK
  • In Place Upgrade from 6.5 to 7.0 (as already mentioned)
  • LVM-snapshots with ext4 and XFS
  • Switch to systemd, firewalld and GRUB2
  • XFS as default file system
  • iSCSI and FCoE in kernel space
  • Support for PTPv2
  • Support for 40G Ethernet Cards
  • Supports installations in UEFI Secure Boot mode on compatible hardware

Major Changes for CentOS 7.1 (1503)

  • As of March 2015 ABRT (>= 2.1.11-19.el7.centos.0.1) can report bugs directly to bugs.centos.org. You can find information about that feature at this page
  • Support for new processors (Intel Broadwell) and graphics (AMD Hawaii)
  • Full support for LVM cache
  • Ability to mount ceph block devices
  • Updated Hyper-V network drivers
  • New libguestfs features
  • Full support for OpenJDK-1.8.0
  • Improved clock stability (for PTP and NTP)
  • Updated Networkmanager packages to version 1.0
  • Updated docker to 1.4.1
  • Updated OpenSSH to 6.6.1
  • New package: Mozilla Thunderbird
  • Update to numerous storage, network and graphics drivers
  • Technology Preview: Support of the Btrfs file system, OverlayFS and the Cisco VIC kernel driver

Major Changes for CentOS 7.2 (1511)

  • Since release 1503 (abrt>= 2.1.11-19.el7.centos.0.1) CentOS-7 can report bugs directly to bugs.centos.org. You can find information about that feature at this page
  • sudo is now capable of verifying command checksums
  • A Kerberos https proxy is now available for identity management
  • NSS no longer accepts DH key parameters < 768 nor RSA/DSA certificates with key sizes < 1024 bits, NSS also now enables TLS1.1/1.2 by default
  • various packages now support TLS1.1/1.2 and EC ciphers
  • The maximum number of SCSI LUNs has been increased
  • The virt-v2v command line tool is now fully supported
  • dd can now show transfer progress
  • OpenJDK7 now supports ECC for TLS connections
  • TPM version 2.0 driver level support has been added
  • tcpdump now supports nanosecond timestamps
  • Various updates to the networking stack (i.e. VXLANs, Data Center TCP, TCP/IP Stack, IPSec, …)
  • Various atomic related packages have been updated
  • Update to the libATA, FCoE and DCB storage drivers
  • Updates to various storage, network and graphics drivers
  • Anaconda now supports NFS when adding additional repos during install
  • Major rebases for the following: Gnome from 3.8 to 3.14, KDE from 4.3 to 4.14, Xorg-X11-Server from 1.15 to 1.17, libreoffice from 4.2.8 to 4.3.7. openldap from 2.4.39 to 2.4.40 and more.

Read more on CentOS 7 Release Notes

I hope this article gives you some ideas and quick guide on where you can download CentOS 7 ISO.