Analysis of changes in CentOS 7 System Configuration

Analysis of changes in CentOS 7 System Configuration

After CentOS 7 is installed, I feel a little powerless at first. Is the change so big?

1. Runlevel
First of all, the original has been using the CentOS-6.5-x86_64-minimal.iso disc image (around m no graphical system is small and convenient), and 7 Currently the smallest image is CentOS-7.0-1406-x86_64-livecd.iso (around M), the default installation is to start the graphical interface, according to the original habits, you need to change to start the command line. The results show that:

[Root @ localhost ~] # Cat/etc/inittab
# Inittab is no longer used when using systemd.
#
# Adding configuration here will have no effect on your system.
#
# Ctrl-Alt-Delete is handled by/etc/systemd/system/ctrl-alt-del.target
#
# Define EMD uses 'targets' instead of runlevels. By default, there are two main targets:
#
# Multi-user.target: analogous to runlevel 3
# Graphical.tar get: analogous to runlevel 5
#
# To set a default target, run:
#
# Ln-sf/lib/systemd/system/<target name>. target/etc/systemd/system/default.tar get
#

Okay, systemd is the only thing in the world (it manages a lot of things. To learn about Centos7, we must first deal with systemd ).

[Root @ localhost ~] # Ls-Xl/etc/systemd/system/*. target
Lrwxrwxrwx. 1 root 36 July 8 23:12/etc/systemd/system/default.tar get->/lib/systemd/system/graphical.tar get

Let's see what the previous runlevel has become?

[Root @ localhost ~] # Ls-Xl/lib/systemd/system
[Root @ localhost ~] # Ls-Xl/lib/systemd/system/runlevel *. target
Lrwxrwxrwx. 1 root 15 Aug 17 00:45/lib/systemd/system/runlevel0.target-> poweroff.tar get
Lrwxrwxrwx. 1 root 13 October 13 00:45/lib/systemd/system/runlevel1.target-> rescue.tar get
Lrwxrwxrwx. 1 root 17 July 5 00:45/lib/systemd/system/runlevel2.target-> multi-user.target
Lrwxrwxrwx. 1 root 17 July 5 00:45/lib/systemd/system/runlevel3.target-> multi-user.target
Lrwxrwxrwx. 1 root 17 July 5 00:45/lib/systemd/system/runlevel4.target-> multi-user.target
Lrwxrwxrwx. 1 root 16 July 5 00:45/lib/systemd/system/runlevel5.target-> graphical.tar get
Lrwxrwxrwx. 1 root 13 October 13 00:45/lib/systemd/system/runlevel6.target-> reboot.tar get

Change the default runlevel to multi-user (it seems that runlevel2 3 4 is no different)

[Root @ localhost ~] # Ln-sf/lib/systemd/system/multi-user.target/etc/systemd/system/default.tar get
[Root @ localhost ~] # Ll-X/etc/systemd/system/*. target
Lrwxrwxrwx. 1 root 37 July 10 09:42/etc/systemd/system/default.tar get->/lib/systemd/system/multi-user.target

Try init 6.

[Root @ localhost ~] # Init 6
Connection to 192.168.150.180 closed by remote host.
Connection to 192.168.150.180 closed.

. :)

Because I changed the prompt for connecting to centos 7 from a desktop version of Linux to Chinese, I need to change the root user language of centos 7 to the original one.

[Root @ localhost ~] # Cp. bashrc. bashrc-back
[Root @ localhost ~] # Echo 'export LANG = "en_Us.UTF-8" '>/root/. bashrc

Use systemctl to add custom system services on CentOS 7

Compile and install LNMP in CentOS 7.0

CentOS 7.0 experiences different from previous versions

Official CentOS 7 release and download

64-bit CentOS 6.5 Installation Method

64-bit CentOS 6.4 dual-system installation in Win7

Precautions for installing CentOS and Windows systems

For more details, please continue to read the highlights on the next page:

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[Content navigation]
Page 1: Runlevel	Page 2nd: Services
Page 3rd: Network	Page 4th: replacing ifconfig route arp netstat with ip ss commands
Page 7: nmtui configure basic network connection	Page 7: nmcli and other network settings
Page 7th: add multiple IP addresses for network interfaces