Docker容器单机网络架构全攻略：深入探索桥接方式的奥秘二 docker网络基础1-底层桥接方式2.1 查看宿主机上网络配置2.1.1 通过ifconfig查看2.1.2 通过ip add list查看2.1.3 通过ip add show查看2.2 查看宿主机上当前的网桥设备2.3 查看宿主机上网络桥接设备 docker0 上学习到的 MAC 地址2.4 查看宿主机上 dns 配置2.5 查看容器上 dns配置

Docker容器单机网络架构全攻略：深入探索桥接方式的奥秘

二 docker网络基础1-底层桥接方式

在docker host中安装docker引擎后，会自动创建docker0 linux bridge，默认情况下所有容器在创建时，都会关联到docker0（默认的linux bridge）；并且在创建容器时docker会给每个容器分配IP地址，网关，域名服务器，如果宿主机可以访问Internet，那么容器也可以访问Internet。

2.1 查看宿主机上网络配置

2.1.1 通过ifconfig查看

[superman@docker ~]$ ifconfig -a

示例：

[superman@docker ~]$ ifconfig -a
docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 172.17.255.255
        inet6 fe80::42:9cff:fe07:27df  prefixlen 64  scopeid 0x20<link>
        ether 02:42:9c:07:27:df  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 13  bytes 1776 (1.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.121  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::bf89:d5fb:2136:8e25  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:ae:f5:f2  txqueuelen 1000  (Ethernet)
        RX packets 6980  bytes 3535173 (3.3 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1827  bytes 202306 (197.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:2b:e7:4a  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0-nic: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether 52:54:00:2b:e7:4a  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[superman@docker ~]$ 

2.1.2 通过ip add list查看

[superman@docker ~]$ ip add list

示例：

[superman@docker ~]$ ip add list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:ae:f5:f2 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.121/24 brd 192.168.0.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::bf89:d5fb:2136:8e25/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:2b:e7:4a brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:2b:e7:4a brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:9c:07:27:df brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:9cff:fe07:27df/64 scope link 
       valid_lft forever preferred_lft forever
[superman@docker ~]$ 

2.1.3 通过ip add show查看

[superman@docker ~]$ ip add show

示例：

[superman@docker ~]$ ip add show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:ae:f5:f2 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.121/24 brd 192.168.0.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::bf89:d5fb:2136:8e25/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:2b:e7:4a brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:2b:e7:4a brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:9c:07:27:df brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:9cff:fe07:27df/64 scope link 
       valid_lft forever preferred_lft forever
[superman@docker ~]$ 

2.2 查看宿主机上当前的网桥设备

[superman@docker ~]$ brctl show

示例：

[superman@docker ~]$ brctl show
bridge name     bridge id               STP enabled     interfaces
docker0         8000.02429c0727df       no
virbr0          8000.5254002be74a       yes             virbr0-nic
[superman@docker ~]$ 

2.3 查看宿主机上网络桥接设备 docker0 上学习到的 MAC 地址

[superman@docker ~]$ brctl showmacs docker0

示例：

[superman@docker ~]$ brctl showmacs docker0
port no mac addr                is local?       ageing timer
  1     7e:e7:1a:c2:e5:11       yes                0.00
  1     7e:e7:1a:c2:e5:11       yes                0.00
[superman@docker ~]$ 

2.4 查看宿主机上 dns 配置

[superman@docker ~]$ cat /etc/resolv.conf

示例：

[superman@docker ~]$ cat /etc/resolv.conf 
# Generated by NetworkManager
nameserver 202.102.224.68
[superman@docker ~]$ 
[superman@docker ~]$ 

2.5 查看容器上 dns配置

[superman@docker ~]$ docker attach superman01
/ # 
/ # cat /etc/resolv.conf 

示例：

[superman@docker ~]$ docker attach superman01
/ # 
/ # cat /etc/resolv.conf 
# Generated by NetworkManager
nameserver 202.102.224.68
/ # 
/ # exit
[superman@docker ~]$ 

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