032、学容器必须懂bridge网络（2019-02-19 周二）

参考https://www.cnblogs.com/CloudMan6/p/7066851.html

 

docker安装时会创建一个名为 docker0 的linuxbridge。如果不指定 --network ，创建的容器默认都会挂在docker0上

 

root@docker-lab:~# docker network ls

NETWORK ID          NAME                DRIVER              SCOPE

b41bf72cd691        bridge              bridge              local

e5cb8d603efd        host                host                local

f9dc6032baba        none                null                local

 

root@docker-lab:~# brctl show

bridge name    bridge id        STP enabled    interfaces

docker0        8000.02420e6cb404    no        

 

root@docker-lab:~# docker run -it -d busybox sh

ef89b9d9c9f300d1369b9178096b700fc48313e7b4696c8fd8c898aff4ee1210

 

root@docker-lab:~# brctl show    #    容器启动后可以看到网桥上多出来了一个接口

bridge name    bridge id        STP enabled    interfaces

docker0        8000.02420e6cb404    no        veth3936bf3

 

root@docker-lab:~# ip address    #    接口信息如下，if5490

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1

 

2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

 

3: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

 

4: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default

 

5491: veth3936bf3@if5490: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default

    link/ether 1e:af:87:1d:eb:7c brd ff:ff:ff:ff:ff:ff link-netnsid 0

    inet6 fe80::1caf:87ff:fe1d:eb7c/64 scope link

       valid_lft forever preferred_lft forever

 

root@docker-lab:~# docker exec -it ef89b9d9c sh

/ # ip address    #    在容器里面查看网卡信息，if5491

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue 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

5490: eth0@if5491: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue

    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff

    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0

       valid_lft forever preferred_lft forever

 

root@docker-lab:~# docker network inspect bridge    #    查看网桥详细信息

[

    {

        "Name": "bridge",

        "Id": "b41bf72cd69194546142efd9b9512c4d7b7fe1b66b3ccb7be982f50ad9881010",

        "Created": "2018-12-25T01:30:26.203579986+08:00",

        "Scope": "local",

        "Driver": "bridge",    #    网桥类型

        "EnableIPv6": false,

        "IPAM": {

            "Driver": "default",

            "Options": null,

            "Config": [

                {

                    "Subnet": "172.17.0.0/16", #    自动分配ip段

                    "Gateway": "172.17.0.1"    #    网关地址

                }

            ]

        },

        "Internal": false,

        "Attachable": false,

        "Ingress": false,

        "ConfigFrom": {

            "Network": ""

        },

        "ConfigOnly": false,

        "Containers": {

            "ef89b9d9c9f300d1369b9178096b700fc48313e7b4696c8fd8c898aff4ee1210": {    #    容器id

                "Name": "nifty_allen",    #    容器name

                "EndpointID": "0ff4b8d824df3103390f19fe2275af23dd06f22d8be8d3782060a5ab20fa0519",

                "MacAddress": "02:42:ac:11:00:02",    #    容器mac

                "IPv4Address": "172.17.0.2/16",       #    容器ip

                "IPv6Address": ""

            }

        },

        "Options": {

            "com.docker.network.bridge.default_bridge": "true",

            "com.docker.network.bridge.enable_icc": "true",

            "com.docker.network.bridge.enable_ip_masquerade": "true",

            "com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",

            "com.docker.network.bridge.name": "docker0",

            "com.docker.network.driver.mtu": "1500"

        },

        "Labels": {}

    }

]

 

root@docker-lab:~# docker ps

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

ef89b9d9c9f3        busybox             "sh"                9 minutes ago       Up 9 minutes                            nifty_allen

 

 

 

 

docker host -- veth3936bf3@if5490

 

container --  eth0@if5491

 

if5490 和 if5491 是一对 veth pair，一头在容器里面，一头在docker host上

 

veth pair技术，在宿主机上创建两个虚拟网络接口 eth0和eth1，veth pair技术的特使是保证无论哪个veth接受到的网络报文，都会无条件的传输给另一方，可以理解成一根管子的两端

 

关于docker bridge的详细介绍，请参考https://blog.csdn.net/mergerly/article/details/79819318