工程文档：
https://wiki.gnome.org/Projects/NetworkManager
RH admin 手册：
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/
nmcli使用手册：
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-network_config_using_nmcli
基本理解之后，直接看help。主要是理解connect，device，等这些概念。
[root@D128 j]# nmcli help
接下来，做一个例子试一下：
增加一个tap设备：
[root@D128 j]# nmcli connection NAME ??UUID ?????????????????????????????????TYPE ???????????DEVICE ens33 ?e4672331-0638-4db8-b818-d6ff50f901af ?802-3-ethernet ?ens33 ?[root@D128 jcloud]# nmcli connection add type tun mode tap ifname tap-nlb con-name tap-nlb autoconnect yes save yesConnection ‘tap-nlb‘ (b3e1db65-4821-4139-95f5-9cba4035ee08) successfully added.[root@D128 j]# nmcli connection NAME ????UUID ?????????????????????????????????TYPE ???????????DEVICE ?ens33 ???e4672331-0638-4db8-b818-d6ff50f901af ?802-3-ethernet ?ens33 ??tap-nlb ?b3e1db65-4821-4139-95f5-9cba4035ee08 ?tun ????????????tap-nlb [root@D128 j]#
生成的配置文件在这里：
[root@D128 j]# cat /etc/NetworkManager/system-connections/tap-nlb [connection]id=tap-nlbuuid=b3e1db65-4821-4139-95f5-9cba4035ee08type=tuninterface-name=tap-nlbpermissions=[tun]mode=2[ipv4]dns-search=method=auto[ipv6]addr-gen-mode=stable-privacydns-search=method=auto
修改禁用tap的DHCP：
[root@D128 ~]# nmcli connection modify tap-nlb ipv4.method link-local
删除tap连接设备：
[root@D128 ~]# nmcli connection delete tap-nlb Connection ‘tap-nlb‘ (b3e1db65-4821-4139-95f5-9cba4035ee08) successfully deleted.
连接在up/down的时候会自动增加或删除设备，可以用nmcli device 查看。
再来个例子，增加一个对外的网桥：
1。加网桥：
[root@D128 ~]# nmcli connection add type bridge ifname br-ext autoconnect yes save yes Connection ‘bridge-br-ext‘ (e886ae77-3a2c-4c93-aee0-4dea8b4d12a8) successfully added.[root@D128 ~]# nmcli connection showNAME ??????????UUID ?????????????????????????????????TYPE ???????????DEVICE bridge-br-ext ?e886ae77-3a2c-4c93-aee0-4dea8b4d12a8 ?bridge ?????????br-ext ens33 ?????????e4672331-0638-4db8-b818-d6ff50f901af ?802-3-ethernet ?ens33 ?[root@D128 ~]# nmcli deviceDEVICE ?TYPE ?????STATE ?????????????????????????????????CONNECTION ???ens33 ??ethernet ?connected ?????????????????????????????ens33 ????????br-ext ?bridge ???connecting (getting IP configuration) ?bridge-br-ext lo ?????loopback ?unmanaged ?????????????????????????????-- ?????
2. 增加slave
[root@D128 ~]# nmcli connection add type bridge-slave ifname ens33 master br-ext
3. 切换连接，从网卡到bridge
[root@D128 jcloud]# nmcli connection down ens33[root@D128 jcloud]# nmcli connection up bridge-slave-ens33
4. 删掉原理的connect
[root@D128 jcloud]# nmcli connection delete ens33
5. reboot 测试
6 成功。networkmanager学会了还是蛮好用的
[root@D128 ~]# ip link1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1 ???link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:002: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br-ext state UP mode DEFAULT qlen 1000 ???link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff3: br-ext: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT qlen 1000 ???link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff[root@D128 ~]# ip addr1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 ???link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 ???inet 127.0.0.1/8 scope host lo ??????valid_lft forever preferred_lft forever ???inet6 ::1/128 scope host ???????valid_lft forever preferred_lft forever2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br-ext state UP qlen 1000 ???link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff3: br-ext: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000 ???link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff ???inet 192.168.50.128/24 brd 192.168.50.255 scope global dynamic br-ext ??????valid_lft 1771sec preferred_lft 1771sec ???inet6 fe80::1ecf:c3cc:4ff6:ef29/64 scope link ???????valid_lft forever preferred_lft forever[root@D128 ~]# brctl showbridge name ???bridge id ???????STP enabled ???interfacesbr-ext ???????8000.000c292fcf32 ???yes ???????ens33
另外：
nmcli加的tap设备，在nmtui中是看不见的。也不能编辑。所以首选还是nmcli。
[administrative][CentOS][NetworkManager] networkmanager （二）
原文地址：https://www.cnblogs.com/hugetong/p/8780424.html