在CentOS7中默认使用NetworkManager守护进程来监控和管理网络设置。nmcli是命令行的NetworkManager工具，会自动把配置写到/etc/sysconfig/network-scripts/目录下面。
NetworkManager最初由 Redhat 公司开发，现在由 GNOME 管理。
CentOS7之前的网络管理是通过ifcfg文件配置管理接口(device)，而现在是通过NetworkManager服务管理连接(connection)。一个接口(device)可以有多个连接(connection)，但是同时只允许一个连接(connection)处于激活（active）状态。
简单理解就是，一个连接就是(connection)就是/etc/sysconfig/network-scripts/目录下的一个配置文件，接口(device)是物理设备，一个物理设置可以拥有多个配置文件，但只能有一个配置文件属于使用(active)状态；配置文件的生成与使用状态均由NetworkManager控制。
当然，依旧支持ifcfg文件配置管理网络，但不推荐。
命令学习
查看帮助
[root@karate ~]# nmcli -h
Usage: nmcli [OPTIONS] OBJECT { COMMAND | help }
OPTIONS
-t[erse] terse output
-p[retty] pretty output
-m[ode] tabular|multiline output mode
-f[ields] <field1,field2,...>|all|common specify fields to output
-e[scape] yes|no escape columns separators in values
-n[ocheck] don't check nmcli and NetworkManager versions
-a[sk] ask for missing parameters
-w[ait] <seconds> set timeout waiting for finishing operations
-v[ersion] show program version
-h[elp] print this help
OBJECT
g[eneral] NetworkManager's general status and operations
n[etworking] overall networking control
r[adio] NetworkManager radio switches
c[onnection] NetworkManager's connections
d[evice] devices managed by NetworkManager
a[gent] NetworkManager secret agent or polkit agent
有六个OBJECT，常用的有connection，device，general查看它们的帮助
[root@karate ~]# nmcli c -h
Usage: nmcli connection { COMMAND | help }
COMMAND := { show | up | down | add | modify | edit | delete | reload | load }
show [--active] [[--show-secrets] [id | uuid | path | apath] <ID>] ...
up [[id | uuid | path] <ID>] [ifname <ifname>] [ap <BSSID>] [passwd-file <file with passwords>]
down [id | uuid | path | apath] <ID> ...
add COMMON_OPTIONS TYPE_SPECIFIC_OPTIONS IP_OPTIONS
modify [--temporary] [id | uuid | path] <ID> ([+|-]<setting>.<property> <value>)+
edit [id | uuid | path] <ID>
edit [type <new_con_type>] [con-name <new_con_name>]
delete [id | uuid | path] <ID>
reload
load <filename> [ <filename>... ]
常用命令
查看接口设备信息
# 简单信息
nmcli device status
# 详细的接口信息
nmcli device show
# 接口的详细信息
nmcli device show interface-name
查看连接(connection)的信息
# 简单信息
nmcli connection show
# 详细的连接信息
nmcli connection show
# 某个连接的详细信息
nmcli connection show connection-name
启动和停止接口
nmcli connection down connection-name
nmcli connection up connection-name
nmcli device disconnect interface-name
nmcli device connect interface-name
建议使用 nmcli dev disconnect interface-name 命令，而不是 nmcli con down connection-name 命令，因为连接断开可将该接口放到“手动”模式，这样做用户让 NetworkManager 启动某个连接前，或发生外部事件（比如载波变化、休眠或睡眠）前，不会启动任何自动连接。
创建连接
nmcli connection add type ethernet con-name connection-name ifname interface-name
nmcli connection add type ethernet con-name connection-name ifname interface-name ip4 address gw4 address
## e.g. 创建一个基于eth1接口的连接
# 创建动态连接，即BOOTPROTO默认为DHCP
[root@localhost ~]# nmcli c add type eth con-name dynamic-eth1 ifname eth1
Connection 'dynamic-eth1' (9c0ad8a9-21f6-40b5-9313-e5c7e4b356f1) successfully added.
# 创建静态连接
[root@localhost ~]# nmcli connection add type eth con-name static-eth1 ifname eth1 ip4 172.16.60.10/24
# nmcli connection add type eth con-name static-eth1 ifname eth1 ip4 172.16.60.10/24 gw4 192.168.60.1
Connection 'static-eth1' (0640bf7f-9490-44a8-be96-2e710fb650e6) successfully added.
创建连接后，NetworkManager 自动将 connection.autoconnect 设定为 yes。还会将设置保存到 /etc/sysconfig/network-scripts/ connection-name 文件中，且自动将 ONBOOT 参数设定为 yes。
激活连接
nmcli connection up connection-name
## e.g. 激活eth1接口的static-eth1连接
[root@localhost ~]# nmcli c up static-eth1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)
修改连接的IP地址
# 可修改的属性可通过以下命令查看
nmcli c show static-eth1
# 修改命令
nmcli connection modify [--temporary] [id | uuid | path] <ID> ([+|-]<setting>.<property> <value>)+
## e.g. 修改连接static-eth1的ip地址
[root@localhost ~]# ip addr | grep eth1
4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 172.16.60.10/24 brd 172.16.60.255 scope global eth1
[root@localhost ~]# nmcli c mod static-eth1 ipv4.addr 172.16.60.20/24
[root@localhost ~]# nmcli c up static-eth1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)
[root@localhost ~]# ip a | grep eth1
4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 172.16.60.20/24 brd 172.16.60.255 scope global eth1
配置连接的DNS
# 设定单个DNS
nmcli connection modify static-eth1 ipv4.dns DNS1
# 设定多个DNS
nmcli connection modify static-eth1 ipv4.dns "DNS1 DNS2"
# 以上命令会替换之前的DNS设置
# 添加某个连接的DNS，需要使用前缀“+”
nmcli connection modify static-eth1 +ipv4.dns DNS3
## e.g. 配置static-eth1连接的DNS
[root@localhost ~]# grep DNS /etc/sysconfig/network-scripts/ifcfg-static-eth1
IPV6_PEERDNS=yes
[root@localhost ~]# nmcli c mod static-eth1 ipv4.dns "114.114.114.114 223.5.5.5"
# 修改连接后，需要重新激活
[root@localhost ~]# nmcli c up static-eth1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/4)
[root@localhost ~]# grep DNS /etc/sysconfig/network-scripts/ifcfg-static-eth1
DNS1=114.114.114.114
DNS2=223.5.5.5
IPV6_PEERDNS=yes
# 新增DNS
[root@localhost ~]# nmcli c mod static-eth1 +ipv4.dns 223.5.5.6
[root@localhost ~]# nmcli c up static-eth1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/5)
[root@localhost ~]# grep DNS /etc/sysconfig/network-scripts/ifcfg-static-eth1
DNS1=114.114.114.114
DNS2=223.5.5.5
DNS3=223.5.5.6
IPV6_PEERDNS=yes
设置主机名
# 查询当前主机名
nmcli general hostname
# 更改主机名
nmcli general hostname my-hostname
# 重启hostnamed服务
systemctl restart systemd-hostnamed
CentOS7下的主机名管理是基于系统服务systemd-hostnamed，服务自身提供了hostnamectl命令用于修改主机名，推荐这种方式进行修改；
使用nmcli命令更改主机名时，systemd-hostnamed服务并不知晓 /etc/hostname 文件被修改，因此需要重启服务去读取配置；
命令交互模式
nmcli con edit
# Valid connection types: generic, 802-3-ethernet (ethernet), pppoe, 802-11-wireless (wifi), wimax, gsm, cdma, infiniband, adsl, bluetooth, vpn, 802-11-olpc-mesh (olpc-mesh), vlan, bond, team, bridge, bond-slave, team-slave, bridge-slave
# 也可以直接指定connection-name进行交互修改
# 还是非交互配置方便
接口绑定(interface bonding)
CentOS7下新增了一种特性team，用于取代bond。
接口绑定步骤是：创建一个组接口(Team interface), 创建一个接口连接，指定网卡接口(device)到组接口里
nmcli connection add type team con-name connection-name ifname interface-name [config JSON]
# JSON 指定所使用的处理器(runner)。JSON语法 '{"runner":{"name":"METHOD"}}'
# METHOD可以是：broadcast、activebackup、roundrobin、loadbalance 或者 lacp
nmcli connection add type team-slave con-name connection-name ifname interface-name master team-name
## e.g. 创建组接口team0，并把eth1和eth2加入其中，网段为192.168.233.0/24
[root@localhost ~]# nmcli d status
DEVICE TYPE STATE CONNECTION
eth0 ethernet connected eth0
eth1 ethernet connected Wired connection 1
eth2 ethernet connected Wired connection 2
lo loopback unmanaged --
[root@localhost ~]# nmcli c show
NAME UUID TYPE DEVICE
Wired connection 2 34494b9d-f056-4f30-841c-7e6fad3b73d0 802-3-ethernet eth2
Wired connection 1 b7ca472c-67f7-4885-ba3b-1b572d3e0d40 802-3-ethernet eth1
eth0 54bd03bd-1300-409b-974f-d98ed3bb8891 802-3-ethernet eth0
[root@localhost ~]# nmcli c del "Wired connection 2"
[root@localhost ~]# nmcli c del "Wired connection 1"
[root@localhost ~]# nmcli c show
NAME UUID TYPE DEVICE
eth0 54bd03bd-1300-409b-974f-d98ed3bb8891 802-3-ethernet eth0
[root@localhost ~]# nmcli d status
DEVICE TYPE STATE CONNECTION
eth0 ethernet connected eth0
eth1 ethernet disconnected --
eth2 ethernet disconnected --
lo loopback unmanaged --
# 创建组接口，并分配ip地址
[root@localhost ~]# nmcli c add type team con-name team0 ifname team0 config '{"runner":{"name":"activebackup"}}' ip4 192.168.233.10/24 gw4 192.168.233.2
Connection 'team0' (4e75c1da-6ce5-4cbc-85fe-da5aa289b7d8) successfully added.
[root@localhost ~]# nmcli c mod team0 ipv4.dns "114.114.114.114 223.5.5.5"
[root@localhost ~]# nmcli c show
NAME UUID TYPE DEVICE
eth0 54bd03bd-1300-409b-974f-d98ed3bb8891 802-3-ethernet eth0
team0 4e75c1da-6ce5-4cbc-85fe-da5aa289b7d8 team team0
# 将网卡接口加入到组接口中
[root@localhost ~]# nmcli c add type team-slave ifname eth1 master team0
Connection 'team-slave-eth1' (3ef0011b-6b69-4dfb-998b-13bf3d729c9c) successfully added.
[root@localhost ~]# nmcli c add type team-slave ifname eth2 master team0
Connection 'team-slave-eth2' (fe3fc939-dbff-485e-aef6-9fbf9f807926) successfully added.
# 启动组接口
[root@localhost ~]# nmcli c up team0
Connection successfully activated (master waiting for slaves) (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/6)
# 查看 team0 当前活动的端口，活动端口基于接口的连接
[root@localhost ~]# teamnl team0 ports
4: eth2: up 1000Mbit FD
3: eth1: up 1000Mbit FD
[root@localhost ~]# nmcli d status
DEVICE TYPE STATE CONNECTION
eth0 ethernet connected eth0
eth1 ethernet connected team-slave-eth1
eth2 ethernet connected team-slave-eth2
team0 team connected team0
lo loopback unmanaged --
[root@localhost ~]# nmcli c show
NAME UUID TYPE DEVICE
eth0 54bd03bd-1300-409b-974f-d98ed3bb8891 802-3-ethernet eth0
team-slave-eth2 fe3fc939-dbff-485e-aef6-9fbf9f807926 802-3-ethernet eth2
team-slave-eth1 3ef0011b-6b69-4dfb-998b-13bf3d729c9c 802-3-ethernet eth1
team0 4e75c1da-6ce5-4cbc-85fe-da5aa289b7d8 team team0
[root@localhost ~]# ip a s team0
5: team0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
link/ether 00:0c:29:d0:a2:77 brd ff:ff:ff:ff:ff:ff
inet 192.168.233.10/24 brd 192.168.233.255 scope global team0
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fed0:a277/64 scope link
valid_lft forever preferred_lft forever
[root@localhost ~]# teamdctl team0 state
setup:
runner: activebackup
ports:
eth2
link watches:
link summary: up
instance[link_watch_0]:
name: ethtool
link: up
eth1
link watches:
link summary: up
instance[link_watch_0]:
name: ethtool
link: up
runner:
active port: eth1
[root@localhost ~]# nmcli c show team0
connection.id: team0
connection.uuid: 4e75c1da-6ce5-4cbc-85fe-da5aa289b7d8
connection.interface-name: team0
connection.type: team
connection.autoconnect: yes
connection.autoconnect-priority: 0
connection.timestamp: 1464621245
connection.read-only: no
connection.permissions:
connection.zone: --
connection.master: --
connection.slave-type: --
connection.secondaries:
connection.gateway-ping-timeout: 0
ipv4.method: manual
ipv4.dns: 114.114.114.114,223.5.5.5
ipv4.dns-search:
ipv4.addresses: 192.168.233.10/24
ipv4.gateway: 192.168.233.2
ipv4.routes:
ipv4.route-metric: -1
ipv4.ignore-auto-routes: no
ipv4.ignore-auto-dns: no
ipv4.dhcp-client-id: --
ipv4.dhcp-send-hostname: yes
ipv4.dhcp-hostname: --
ipv4.never-default: no
ipv4.may-fail: yes
ipv6.method: auto
ipv6.dns:
ipv6.dns-search:
ipv6.addresses:
ipv6.gateway: --
ipv6.routes:
ipv6.route-metric: -1
ipv6.ignore-auto-routes: no
ipv6.ignore-auto-dns: no
ipv6.never-default: no
ipv6.may-fail: yes
ipv6.ip6-privacy: -1 (unknown)
ipv6.dhcp-send-hostname: yes
ipv6.dhcp-hostname: --
team.config: {"runner":{"name":"activebackup"}}
GENERAL.NAME: team0
GENERAL.UUID: 4e75c1da-6ce5-4cbc-85fe-da5aa289b7d8
GENERAL.DEVICES: team0
GENERAL.STATE: activated
GENERAL.DEFAULT: no
GENERAL.DEFAULT6: no
GENERAL.VPN: no
GENERAL.ZONE: --
GENERAL.DBUS-PATH: /org/freedesktop/NetworkManager/ActiveConnection/6
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/Settings/3
GENERAL.SPEC-OBJECT: /
GENERAL.MASTER-PATH: --
IP4.ADDRESS[1]: 192.168.233.10/24
IP4.GATEWAY: 192.168.233.2
IP4.DNS[1]: 114.114.114.114
IP4.DNS[2]: 223.5.5.5
IP6.ADDRESS[1]: fe80::20c:29ff:fed0:a277/64
测试的话，可以开个ping窗口持续ping，然后禁用team0组中的eth2；理论上ping包是不会丢失的。
# 关闭eth2网卡，看ping状态
[root@localhost ~]# nmcli d dis eth2
Device 'eth2' successfully disconnected.
[root@localhost ~]# teamdctl team0 state
setup:
runner: activebackup
ports:
eth1
link watches:
link summary: up
instance[link_watch_0]:
name: ethtool
link: up
runner:
active port: eth1
[root@localhost ~]# nmcli d con eth2
Device 'eth2' successfully activated with 'fe3fc939-dbff-485e-aef6-9fbf9f807926'.
[root@localhost ~]# teamdctl team0 state
setup:
runner: activebackup
ports:
eth1
link watches:
link summary: up
instance[link_watch_0]:
name: ethtool
link: up
eth2
link watches:
link summary: up
instance[link_watch_0]:
name: ethtool
link: up
runner:
active port: eth1
[root@localhost ~]# teamnl team0 options
queue_id (port:eth2) 0
priority (port:eth2) 0
user_linkup_enabled (port:eth2) false
user_linkup (port:eth2) true
enabled (port:eth2) false
queue_id (port:eth1) 0
priority (port:eth1) 0
user_linkup_enabled (port:eth1) false
user_linkup (port:eth1) true
enabled (port:eth1) true
activeport 3
mcast_rejoin_interval 0
mcast_rejoin_count 1
notify_peers_interval 0
notify_peers_count 1
mode activebackup
