centos7.0版本之后相对于以前的版本更改行还是很大的，原先在6.5版本之前命令和配置文件大致都差不多，自7.0版本之后一些功能都有较大的改变，接下来会从防火墙和服务的相关配置来进行剖析。

（一）防火墙firewall的相关介绍及配置

CentOS 7中防火墙是一个非常的强大的功能，在CentOS 6.5中在iptables防火墙中进行了升级了。(he dynamic firewall daemon firewalld provides a dynamically managed firewall with support for network “zones” to assign a level of trust to a network and its associated connections and interfaces. It has support for IPv4 and IPv6 firewall settings. It supports Ethernet bridges and has a separation of runtime and permanent configuration options. It also has an interface for services or applications to add firewall rules directly-----官方文档)

firewall--区域zone

网络区域定义了网络连接的可信等级。这是一个 一对多的关系，这意味着一次连接可以仅仅是一个区域的一部分，而一个区域可以用于很多连接。那个区域是否可用室友firewall提供的区域按照从不信任到信任的顺序排序。

firewall 分类

Firewalls can be used to separate networks into different zones based on the level of trust the user has decided to place on the devices and traffic within that network. NetworkManager informs firewalld to which zone an interface belongs. An interface’s assigned zone can be changed by NetworkManager or via the firewall-config tool which can open the relevant NetworkManager window for you.

The zone settings in /etc/firewalld/ are a range of preset settings which can be quickly applied to a network interface. They are listed here with a brief explanation:

drop
Any incoming network packets are dropped,there is no reply. Only outgoing network connections are possible.

block
Any incoming network connections are rejected with an icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited for IPv6. Only network connections initiated from within the system are possible.

public
For use in public areas. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.

external
For use on external networks with masquerading enabled especially for routers. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.

dmz
For computers in your demilitarized zone that are publicly-accessible with limited access to your internal network. Only selected incoming connections are accepted.

work
For use in work areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.

home
For use in home areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.

internal
For use on internal networks. You mostly trust the other computers on the networks to not harm your computer. Only selected incoming connections are accepted.

trusted
All network connections are accepted.
It is possible to designate one of these zones to be the default zone. When interface connections are added to NetworkManager,they are assigned to the default zone. On installation,the default zone in firewalld is set to be the public zone.

firewall相关的配置:

1，系统配置目录：/usr/lib/firewalld

[root@iZbp1hxo8urkhrybu3wwhyZfirewalld]#cd/usr/lib/firewalld
[root@iZbp1hxo8urkhrybu3wwhyZfirewalld]#ls
icmptypesservicesxmlschemazones
[root@iZbp1hxo8urkhrybu3wwhyZfirewalld]#cdservices/
[root@iZbp1hxo8urkhrybu3wwhyZservices]#ls
amanda-client.xmlhigh-availability.xmlldap.xmlpmproxy.xmlsamba.xml
bacula-client.xmlhttps.xmllibvirt-tls.xmlpmwebapis.xmlsmtp.xml
bacula.xmlhttp.xmllibvirt.xmlpmwebapi.xmlssh.xml
dhcpv6-client.xmlimaps.xmlmdns.xmlpop3s.xmltelnet.xml
dhcpv6.xmlipp-client.xmlmountd.xmlpostgresql.xmltftp-client.xml
dhcp.xmlipp.xmlms-wbt.xmlproxy-dhcp.xmltftp.xml
dns.xmlipsec.xmlMysqL.xmlradius.xmltransmission-client.xml
freeipa-ldaps.xmliscsi-target.xmlnfs.xmlRH-Satellite-6.xmlvdsm.xml
freeipa-ldap.xmlkerberos.xmlntp.xmlrpc-bind.xmlvnc-server.xml
freeipa-replication.xmlkpasswd.xmlopenvpn.xmlrsyncd.xmlwbem-https.xml
ftp.xmlldaps.xmlpmcd.xmlsamba-client.xml
[root@iZbp1hxo8urkhrybu3wwhyZservices]#

注意：目录中存放定义好的网络服务和端口参数，系统参数，不能修改。

2，用户配置目录：/etc/firewalld/

[root@iZbp1hxo8urkhrybu3wwhyZfirewalld]#cd/etc/firewalld/
[root@iZbp1hxo8urkhrybu3wwhyZfirewalld]#ls
firewalld.conficmptypeslockdown-whitelist.xmlserviceszones

3,用户如何自定义添加端口，分为使用命令行添加和修改相关的配置文件。

3.1，使用命令的方式添加

[root@iZbp1hxo8urkhrybu3wwhyZservices]#firewall-cmd--zone=public--permanent--add-port=8080/tcp
success
[root@iZbp1hxo8urkhrybu3wwhyZservices]#firewall-cmd--reload

参数介绍：

1、firewall-cmd：是Linux提供的操作firewall的一个工具；

2、--permanent：表示设置为持久；

3、--add-port：标识添加的端口

4、--zone:指定某个区域

5、firewall-cmd --reload ：重启生效

3.2修改配置文件方式添加端口

[root@iZbp1hxo8urkhrybu3wwhyZzones]#vim/usr/lib/firewalld/zones/public.xml
<?xmlversion="1.0"encoding="utf-8"?>
<zone>
<short>Public</short>
<description>Foruseinpublicareas.Youdonottrusttheothercomputersonnetworkstonotharmyourcomputer.O
nlyselectedincomingconnectionsareaccepted.</description>
<servicename="ssh"/>
<servicename="dhcpv6-client"/>
<rulefamily="ipv4">
<sourceaddress="127.0.0.1"/>
<portprotocol="tcp"port="10050-10051"/>
<accept/>
</rule>
</zone>

firewall常用命令：

1，重启，关闭开启firewall.service服务

[root@iZbp1hxo8urkhrybu3wwhyZzones]#servicefirewalldrestart
Redirectingto/bin/systemctlrestartfirewalld.service
[root@iZbp1hxo8urkhrybu3wwhyZzones]#servicefirewalldstop
Redirectingto/bin/systemctlstopfirewalld.service
[root@iZbp1hxo8urkhrybu3wwhyZzones]#servicefirewalldstart
Redirectingto/bin/systemctlstartfirewalld.service

2，查看firewalld服务状态：

[root@iZbp1hxo8urkhrybu3wwhyZzones]#systemctlstatusfirewalld
●firewalld.service-firewalld-dynamicfirewalldaemon
Loaded:loaded(/usr/lib/systemd/system/firewalld.service;disabled;vendorpreset:enabled)
Active:active(running)sinceWed2017-04-1911:10:50CST;43sago
MainPID:4290(firewalld)
CGroup:/system.slice/firewalld.service
└─4290/usr/bin/python-Es/usr/sbin/firewalld--nofork--nopid
Apr1911:10:50iZbp1hxo8urkhrybu3wwhyZsystemd[1]:Startingfirewalld-dynamicfirewalldaemon...
Apr1911:10:50iZbp1hxo8urkhrybu3wwhyZsystemd[1]:Startedfirewalld-dynamicfirewalldaemon.

3，查看firewall的状态

[root@iZbp1hxo8urkhrybu3wwhyZzones]#firewall-cmd--state
running

4,查看防火墙firewall规则

[root@iZbp1hxo8urkhrybu3wwhyZ~]#firewall-cmd--list-all
public(default)
interfaces:
sources:
services:dhcpv6-clientssh
ports:10050/tcp8080/tcp10051/tcp
masquerade:no
forward-ports:
icmp-blocks:
richrules:

后注：如果感觉firewall防火墙玩不好，可以关闭firewall而安装iptables,具体步骤如下

[root@iZbp1hxo8urkhrybu3wwhyZ~]#servicefirewalldstop####停止firewalld服务
Redirectingto/bin/systemctlstopfirewalld.service
[root@iZbp1hxo8urkhrybu3wwhyZ~]#systemctldisablefirewalld.service####禁止firewalld开机启动
[root@iZbp1hxo8urkhrybu3wwhyZ~]#yuminstalliptables-services#####安装iptables
Loadedplugins:fastestmirror
Repodataisover2weeksold.Installyum-cron?Orrun:yummakecachefast
base|3.6kB00:00:00
epel|4.3kB00:00:00
extras|3.4kB00:00:00
updates|3.4kB00:00:00
[root@iZbp1hxo8urkhrybu3wwhyZ~]#vim/etc/sysconfig/iptables########编辑iptables配置文件
[root@iZbp1hxo8urkhrybu3wwhyZ~]#serviceiptablesstart#开启
[root@iZbp1hxo8urkhrybu3wwhyZ~]#systemctlenableiptables.service#设置防火墙开机启动

备注：centos7.Xfireward防火墙基本使用：

1、firewalld的基本使用
启动：systemctlstartfirewalld
查看状态：systemctlstatusfirewalld
停止：systemctldisablefirewalld
禁用：systemctlstopfirewalld

2.systemctl是CentOS7的服务管理工具中主要的工具，它融合之前service和chkconfig的功能于一体。
启动一个服务：systemctlstartfirewalld.service关闭一个服务：systemctlstopfirewalld.service重启一个服务：systemctlrestartfirewalld.service显示一个服务的状态：systemctlstatusfirewalld.service在开机时启用一个服务：systemctlenablefirewalld.service在开机时禁用一个服务：systemctldisablefirewalld.service查看服务是否开机启动：systemctlis-enabledfirewalld.service查看已启动的服务列表：systemctllist-unit-files|grepenabled查看启动失败的服务列表：systemctl--Failed
3.配置firewalld-cmd
查看版本：firewall-cmd--version
查看帮助：firewall-cmd--help
显示状态：firewall-cmd--state
查看所有打开的端口：firewall-cmd--zone=public--list-ports
更新防火墙规则：firewall-cmd--reload
查看区域信息:firewall-cmd--get-active-zones
查看指定接口所属区域：firewall-cmd--get-zone-of-interface=eth0
拒绝所有包：firewall-cmd--panic-on
取消拒绝状态：firewall-cmd--panic-off
查看是否拒绝：firewall-cmd--query-panic

那怎么开启一个端口呢
添加
firewall-cmd--zone=public--add-port=80/tcp--permanent（--permanent永久生效，没有此参数重启后失效）
重新载入
firewall-cmd--reload
查看
firewall-cmd--zone=public--query-port=80/tcp
删除
firewall-cmd--zone=public--remove-port=80/tcp--permanent

（二）centos 7.x添加自定义服务

Centos 系统服务脚本目录：

/usr/lib/systemd/

有系统（system）和用户（user）之分，

如需要开机没有登陆情况下就能运行的程序，存在系统服务（system）里，即：

/lib/systemd/system/

反之，用户登录后才能运行的程序，存在用户（user）里

服务以.service结尾。

这边以Nginx开机运行为例

1,建立服务文件

[root@iZbp1h901rvv69gdzz4l75Zsystem]#vimNginx.service
[Unit]
Description=Nginx
After=network.target
[Service]
Type=forking
ExecStart=/usr/local/Nginx/sbin/Nginx
ExecReload=/usr/local/Nginx/sbin/Nginx-sreload
ExecStop=/usr/local/Nginx/sbin/Nginx-squit
PrivateTmp=true
[Install]
WantedBy=multi-user.target

说明：

Unit]:服务的说明

Description:描述服务
After:描述服务类别

[Service]服务运行参数的设置

Type=forking是后台运行的形式
ExecStart为服务的具体运行命令
ExecReload为重启命令
ExecStop为停止命令
PrivateTmp=True表示给服务分配独立的临时空间
注意：[Service]的启动、重启、停止命令全部要求使用绝对路径

[Install]服务安装的相关设置，可设置为多用户

2，保存该文件，并赋予754权限

[root@iZbp1h901rvv69gdzz4l75Zsystem]#chmod754Nginx.service
[root@iZbp1h901rvv69gdzz4l75Zsystem]#llNginx.service
-rwxr-xr--1rootroot258Apr1914:39Nginx.service

3，设置开机自启动

[root@iZbp1h901rvv69gdzz4l75Zsystem]#systemctlenableNginx.service
[root@iZbp1h901rvv69gdzz4l75Zsystem]#systemctllist-unit-files|grepenabled|grepNginx.service
Nginx.serviceenabled

其他相关的命令

systemctl 是系统服务管理器命令，它实际上将 service 和 chkconfig 这两个命令组合到一起。

检查服务状态启动某服务重启某服务

任务	旧指令	新指令
使某服务自动启动	chkconfig �Clevel 3 httpd on	systemctl enable httpd.service
使某服务不自动启动	chkconfig �Clevel 3 httpd off	systemctl disable httpd.service
service httpd status	systemctl statushttpd.service （服务详细信息） systemctl is-active httpd.service （仅显示是否 Active)
显示所有已启动的服务	chkconfig �Clist	systemctl list-units |grep enabled
service httpd start	systemctl start httpd.service
停止某服务	service httpd stop	systemctl stop httpd.service
service httpd restart	systemctl restart httpd.service

启动Nginx服务
systemctlstartNginx.service
设置开机自启动
systemctlenableNginx.service
停止开机自启动
systemctldisableNginx.service
查看服务当前状态
systemctlstatusNginx.service
重新启动服务
systemctlrestartNginx.service
查看所有已启动的服务
systemctllist-units--type=service
分类:网络
列出所有服务的层级和依赖关系，可以指定某个服务
systemctllist-dependencies[服务名称]

备注:

　　1. 列出所有可用单元

　　# systemctl list-unit-files

　　2. 列出所有运行中单元

　　# systemctl list-units

　　3. 列出所有失败单元

　　# systemctl �CFailed

　　4. 检查某个单元（如 crond.service）是否启用

　　# systemctl is-enabled crond.service

　　5. 列出所有服务

　　# systemctl list-unit-files �Ctype=service

列出所有服务：systemctl list-unit-files|grep enabled

6. Linux中如何启动、重启、停止、重载服务以及检查服务（如 httpd.service）状态

　　# systemctl start httpd.service

　　# systemctl restart httpd.service

　　# systemctl stop httpd.service

　　# systemctl reload httpd.service

　　# systemctl status httpd.service

　　注意：当我们使用systemctl的start，restart，stop和reload命令时，终端不会输出任何内容，只有status命令可以打印输出。

7. 如何激活服务并在开机时启用或禁用服务（即系统启动时自动启动MysqL.service服务）

　　# systemctl is-active MysqL.service

　　# systemctl enable MysqL.service

　　# systemctl disable MysqL.service

8. 使用systemctl命令杀死服务

　　# systemctl kill crond

9. 检查某个服务的所有配置细节

　　# systemctl show MysqL

附注：RHEL7和RHEL6的主要变化

RHEL7和RHEL6的主要变化
	RHEL7	RHEL6
文件系统	XFS	EXT4
内核版本	3.10.x-x系列	2.6.x-x系列
内核名称	Maipo	Santiago
发布时间	2014-06-09（3.10.0-123）	2010-11-09（2.6.32-71）
进程名称	systemd	init
运行级别	runlevel0.target->poweroff.target runlevel1.target->rescue.target runlevel2.target->multi-user.target runlevel3.target->multi-user.target runlevel4.target->multi-user.target runlevel5.target->graphical.target runlevel6.target->reboot.target /etc/systemd/system/default.target	runlevel0 runlevel1 runlevel2 runlevel3 runlevel4 runlevel5 runlevel6 /etc/inittab
主机名称	/etc/hostname	/etc/sysconfig/network
容量上限	500TB	16TB
内存上限	64TB	-
cpu个数	5120个，SMP(Symmetric Multi-Processors)技术
检查工具	xfs.repair	e2fsck
启动工具	GRUB2	GRUB0.97
服务启动	Systemd	Upstart
服务管理	systemctl enable xxx.service systemctl start xxx.service systemctl stop xxx.service systemctl restart xxx.service 兼容chkconfig，service命令	service enable xxx.service service stop xxx.service service start xxx.service chkconfig --level 3 5 nfs on
防火墙	Firewalld兼容Iptables	Iptables
网络绑定	Team Driver	Bonding
网络时间	Chrony，ntpd	ntpd
NFS版本	NFS4.1支持NFSv3，NFSv4.0，NFSv4.1客户端	NFS4
集群管理工具	Pacemaker	Rgmanager
负载均衡工具	Keepalived，HAProxy	Rgmanager
桌面环境	GNOME3,KDE4.10	GNOME2
数据库	MariaDB	MysqL
RHEL7和RHEL6的管理命令和配置文件的变化
订阅信息	RHEL7	RHEL6
订阅信息工具	subscription-manager identity	/etc/sysconfig/rhn/systemid subscription-manager identity
配置订阅信息	subscription-manager rhn_register	rhn_register rhnreg_kssubscription-manager identity
基本配置	RHEL7	RHEL6
GUI配置工具	gnome-control-center	system-config-*
网络配置工具	nmcli nmtui nm-connection-editor	system-config-network
语言配置工具	localectl	system-config-language
时间配置工具	timedatectl date	system-config-date date
时间同步	ntpdate /etc/chrony.conf	ntpdate /etc/ntp.conf
键盘配置	localectl	system-config-keyboard
服务管理	RHEL6
服务列表	systemctl -at service ls /{usr/lib,etc}/systemd/system/*.service	chkconfig ls /etc/init.d/
服务启动	systemctl start name.service	service name start
服务停止	systemctl stop name.service	service name stop
服务查看	systemctl status name.service	service namestatus
服务重启	systemctl restart name.service	service namerestart
服务开机自启	systemctlenablename.service	chkconfig name on
服务开机不自启	systemctl disablename.service	chkconfig name off
添加服务	systemctl daemon-reload	achkconfig --add
服务列表查看	systemctl -t service --state=active	service --status-all
查看运行级别	systemctl get-default	runlevel
修改运行级别	systemctl isolate name.target init runlevel	init runlevel
日志文件	/etc/rsyslog.conf /etc/rsyslog.d/*.conf /var/log/journal/ /etc/systemd/journald.conf	/etc/rsyslog.conf
查看日志文件	/var/log/	/var/log/journalctl
内核硬件	RHEL7	RHEL6
启动提示符	append rd.break or init=/bin/bash to kernel cmdline	append 1 or s or init=/bin/bash to kernel cmdline
关闭系统	systemctlshutdown	shutdown
关闭电源	systemctl poweroff	poweroff
挂起系统	systemctl halt	halt
重启系统	systemctlreboot	reboot
修改运行级别	systemctl set-default	/etc/inittab
配置GRUB	/etc/default/grub grub2-mkconfig grub-set-default	/boot/grub/grub.conf
软件管理	RHEL7	RHEL6
安装软件包	yum install yum group install	yum install yum groupinstall
查看软件包	yum info yum group info	yum info yum groupinfo
文件系统	RHEL7	RHEL6
建立文件系统	fdisk parted gdisk	fdisk parted
LVM管理	vgextend lvextend xfs_growfs	vgextend lvextend resize2fs
网络接口配置	RHEL7	RHEL6
配置名称	/etc/hosts /etc/resolv.conf nmcli conmod	/etc/hosts /etc/resolv.conf
主机名称配置	/etc/hostname hostnamectl nmcli	/etc/sysconfig/network
Ip地址配置	ip addr nmcli dev show teamdctl brctl bridge	ip add ifconfig brctl
配置防火墙	firewall-cmd firewall-config	iptables&ip6tables /etc/sysconfig/ip*tables system-config-firewall
查看端口命令	ss lsof	netstat ss lsof