CentOS 7 vs. CentOS 6 different

(1) Desktop system

[CentOS6] GNOME 2.x

[CentOS7] Gnome 3.x (Gnome Shell)

(2) file system

[CentOS6] Ext4

[CentOS7] Xfs

(3) Kernel version

[CentOS6] 2.6.x-x

[CentOS7] 3.10.x-x

(4) Boot loader

[CentOS6] GRUB Legacy (+efibootmgr)

[CentOS7] GRUB2

(5) Firewall

[CentOS6] Iptables

[CentOS7] Firewalld

(6) Default database

[CentOS6] Mysql

[CentOS7] MariaDB

(7) File structure

[CentOS6]/bin,/sbin,/lib, and/lib64 in/under

[CentOS7]/bin,/sbin,/lib, and/lib64 move to/usr

(8) Host name

[CentOS6]/etc/sysconfig/network

[CentOS7]/etc/hostname

$ hostnamectl set-hostname OraRacNode1

(9) Time synchronization

[CentOS6]

$ ntp

$ ntpq-p

[CentOS7]

$ chrony

$ CHRONYC Sources

(10) Modification time

[CentOS6]

$ vim/etc/sysconfig/clock

Zone= "Asia/tokyo"

Utc=fales

$ sudo ln-s/usr/share/zoneinfo/asia/tokyo/etc/localtime

[CentOS7]

$ timedatectl Set-timezone Asia/tokyo

$ TIMEDATECTL Status

(11) Modified Area

[CentOS6]

$ vim/etc/sysconfig/i18n

Lang= "Ja_jp.utf8"

$/etc/sysconfig/i18n

$ locale

[CentOS7]

$ localectl Set-locale Lang=ja_jp.utf8

$ LOCALECTL Status

(12) Service-related

1) Start stop

[CentOS6]

$ service Service_Name Start

$ Service Service_Name Stop

$ service sshd Restart/status/reload

[CentOS7]

$ systemctl Start service_name

$ systemctl Stop Service_Name

$ systemctl restart/status/reload sshd

2) Self-priming

[CentOS6]

$ chkconfig service_name on/off

[CentOS7]

$ systemctl Enable Service_Name

$ systemctl Disable service_name

For example:

Start a service: Systemctl start Postfix.service

Close a service: Systemctl stop Postfix.service

Restart a service: Systemctl restart Postfix.service

Displays the status of a service: Systemctl status Postfix.service

Enable a service at boot: Systemctl enable Postfix.service

Disable a service at boot: systemctl disable Postfix.service

Check to see if the service is booting: Systemctl is-enabled Postfix.service;echo $?

To view a list of services that have been started: Systemctl List-unit-files|grep enabled

Description: The Enable service is in the current "runlevel" configuration file directory/etc/systemd/system/multi-user.target.wants/, establish/usr/lib/systemd/ A soft link within the system that corresponds to the service profile; Disabling the service is removing the soft link.

(1) The SYSTEMD uses a more free target alternative than the Sysvinit run level.

The 3rd run level is replaced with Multi-user.target. The 5th run level is replaced with Graphical.target. Runlevel3.target and Runlevel5.target are symbolic links that point to Multi-user.target and Graphical.target, respectively.
You can use the following command to switch to run Level 3:
Systemctl isolate Multi-user.target or Systemctl isolate Runlevel3.target
You can use the following command to switch to run Level 5:
Systemctl isolate Graphical.target or Systemctl isolate Runlevel5.target

(2) How do I change the default runlevel?
SYSTEMD uses links to point to the default runlevel. Before creating a new link, you can delete the existing link by following the command: Rm/etc/systemd/system/default.target
Default startup Run Level 3:
Ln-sf/lib/systemd/system/multi-user.target/etc/systemd/system/default.target
Default startup Run Level 5:
Ln-sf/lib/systemd/system/graphical.target/etc/systemd/system/default.target
SYSTEMD does not use/etc/inittab files.

(3) How do I check the current runlevel?
The old RunLevel command can still be used under SYSTEMD. You can continue to use it, although SYSTEMD replaces the previous system's runlevel with the ' target ' concept (multiple ' target ' can be activated simultaneously).
The equivalent SYSTEMD command is Systemctl list-units–type=target

3) Services at a glance

[CentOS6]

$ chkconfig--list

[CentOS7]

$ systemctl List-unit-files

$ systemctl--type Service

4) Force stop

[CentOS6]

$ kill-9 <PID>

[CentOS7]

$ systemctl Kill--signal=9 sshd

(13) Network

1) Network Information

[CentOS6]

$ netstat

$ netstat-i

$ netstat-n

[CentOS7]

$ IP N

$ ip-s L

$ ss

2) IP address MAC address

[CentOS6]

$ ifconfig-a

[CentOS7]

$ IP Address Show

$ NMCLI Connection Show

3) routing

[CentOS6]

$ route-n

$ route-a Inet6-n

[CentOS7]

$ IP Route Show

$ ip-6 Route Show

(14) Restart shutdown

1) Close

[CentOS6]

$ shutdown-h Now

[CentOS7]

$ poweroff

$ systemctl Poweroff

2) Restart

[CentOS6]

$ reboot

$ shutdown-r Now

[CentOS7]

$ reboot

$ systemctl Reboot

3) Single user mode

[CentOS6]

$ init S

[CentOS7]

$ systemctl Rescue

4) Startup mode

[CentOS6]

[Guicui]

$ vim/etc/inittab

Id:3:initdefault:

[Cuigui]

$ startx

[CentOS7]

[Guicui]

$ systemctl Isolate Multi-user.target

[Cuigui]

$systemctl Isolate Graphical.target

Default

$ systemctl Set-default Graphical.target

$ systemctl Set-default Multi-user.target

Current

$ systemctl Get-default

　　　　

SYSTEMD-CGLS lists the running processes in a tree, which can recursively display control group content

Reference:

http://urashita.com/archives/1538

Http://qiita.com/sion_cojp/items/115e1671fcbc8f214aee

Https://www.upken.jp/kb/cent6-cent7.html

Http://inaba-serverdesign.jp/blog/20141110/centos7.html

CentOS 7 vs. CentOS 6 different