Several new features of CentOS 7

In the previous article, we mentioned that ifconfig is not a new feature of centos7 by default, so I searched for its new features on the internet and found an article.

Centos least-optimized installation without the ifconfig command

Centos7.0 has just been installed. The installation is minimized. If the ifconfig command is not found, ens32 is displayed on the NIC of the VM. This is a feature of centos7.0. Use the ifconfig command, in/etc/sysconfig/network-scripts/if-ens32 to configure the network, remember onboot = on this option must be set, or the network can not start, restart the network,/etc/init. d/network restart use centos's official yum source

Yum clean all

Yum install net-tools

The ifconfig command is in the net-tools package.

Nslookup, dig in bind-utils

Centos uses systemd instead of sysvinit

Systemd usage:

Systemd service management program

Systemctl is the most important tool. It integrates the functions of service and chkconfig. You can use it to enable or disable services permanently or only in the current session.

Run the following command to list running services or other: systemctl

For more information, see man systemctl ). Systemd-cgls lists running processes in a tree. It recursively displays the content of a given control group. For more information, see systemd-cgls manual.

How do I start, disable, enable, and disable a service?

Run a service:

Systemctl start foo. service:

Systemctl stop foo. service restart a service:

Systemctl restart foo. service

Displays the status of a service (whether running or not): systemctl status foo. service

Enable a service at startup: systemctl enable foo. service

Disable a service at startup: systemctl disable foo. service

Check if the service is started: systemctl is-enabled iptables. service; echo $?

Modify the running level:

 

Systemd uses a more free target concept than sysvinit.

3rd run-level replacement with multi-user.target. 5th use graphical.tar get to replace the runtime class. Runlevel3.target and runlevel5.target are symbolic links to multi user.targetand graphical.tar get respectively.

You can use the following command to switch to "runtime level 3 ":

Systemctl isolate multi-user.target (or)

Systemctl isolate runlevel3.target

You can also use the following command to switch to "running level 5 ":

Systemctl isolate graphical.tar get (or)

Systemctl isolate runlevel5.target

How can I change the default running level?

Systemd uses links to point to the default running level. Before creating a new link, you can run the following command to delete the existing link: rm/etc/systemd/system/default.tar get

Switch to runtime level 3 by default:

Ln-sf/lib/systemd/system/multi-user.target/etc/systemd/system/default.tar get

Switch to running level 5 by default:

Ln-sf/lib/systemd/system/graphical.tar get/etc/systemd/system/default.tar get

Systemd does not use the/etc/inittab file. How can I view the current running level?

The runlevel command can still work in systemd. You can continue to use it, although systemd uses the 'target' concept (multiple 'targets' can be activated at the same time) to replace the runlevel of the previous system.

The equivalent systemd command is

Systemctl list-units -- type = target

Guide Mode:

Use grub2 pilot

Grub2 features:

1. Modular design

Unlike Grub's single kernel structure, Grub 2 features are distributed in many small modules and can be dynamically loaded and detached during runtime.

2. Support for multiple architectures

Grub 2 supports different systems such as PC (i386) and MAC (powerpc), and supports the latest EFI Architecture.

3. International support

Grub 2 supports non-English languages.

4. Memory management

Grub 2 has a real memory management system.

5. Script language

Grub 2 supports scripting languages, such as conditions, loops, variables, and functions.

This article is from the "linux & python" blog, please be sure to keep this http://mikeluwen.blog.51cto.com/5619187/1435873

Several new features of CentOS 7 (for example)