CentOS 7 was officially released in July, 2014. There are many significant changes in it. So you have to learn how they are if you want to use it or smoothly migrate settings from the previous version.

1. A brief introduction to
CentOS 7
Taizo Ito <taizo.ito@hde.co.jp>
HDE, Inc.

2. There are many changes
Including very important changes. Some of them are new
features.
- systemd （* new feature）
- firewalld （* new feature）
- Network management method (NetworkManager)
and some OSSs are significantly changed.

3. systemd
Process and service management system
● SystemVinit or upstart is replaced with it.
● Uses D-Bus as a backend

4. firewalld
Packet filter management system
● Set up filter policy by combining predefined
zone and service
● Uses iptables as a backend
● cons: Can’t configure OUTPUT chain

5. NetworkManager
A dynamic network control daemon
● Network management is unified with
NetworkManager
● Traditional ifcfg style is still supported
● It provides some CLIs to control and
configure network (a little difficult to use it)
● Also uses D-Bus

6. OSS Updates
Some of them are very important changes for our products.
● Apache
From 2.2 to 2.4
Not a few directives are deprecated. Order/Allow/Deny directives
● MariaDB
New CentOS provides it instead of MySQL.
Basically both are the same things. No need to much effort to migrate
● etc...

7. To sum up,
- There are many significant changes in the new CentOS.
- The new CentOS largely depends on D-Bus.
Therefore,
If you want to use it comfortably and migrate old settings
correctly, you should learn about these changes as well as
D-Bus system.

8. Thank you
Taizo Ito <taizo.ito@hde.co.jp>
HDE, Inc.