一. 容器網路模型：
Docker定義了一個非常簡單的網路模型，叫做container network model(CNM).如下圖所示：
CNM模型有三個元素—sandbox, endpoint, 和network
- sandbox：不允許從外面的網路連線到容器，實現了完美的隔離功能。
- Endpoint: 終端節點可以認為是network到sandbox中間的一個節點，可以想像成是到容器的一個門。
- network: 是終端和終端之間進行通訊的保障。也是一個特別重要的元件。
下圖描述了容器網路常見的幾種方式和作用範圍：
| Network | Company | Scope | Description |
| Bridge | Docker | local | Simple network based on Linux bridges allowing networking on a single host |
| Macvlan | Docker | Local |
Configures multiple layer 2(that is, MAC) addresses on a single physical host interface |
| Overlay | Docker | Global | Multinode-capable container network based on Virtual Extensible LAN(VXLan) |
| Weave Net | Weaveworks | Global | Simple, resilient, multihost Docker networking |
| Contiv Network Plugin | Cisco | Global | Open source container networking |
二. The bridge network
1. 建立bridge
(1) 檢查bridge資訊
[root@c720120 ~]# docker network inspect bridge
[
{
“Name”: “bridge”,
“Id”: “8d4ce133354ba6e3ab01684cf18b88535230647e78a6d698f1ef8d79f767b169”,
“Created”: “2018-05-29T22:57:29.986412028+08:00”,
“Scope”: “local”,
“Driver”: “bridge”,
“EnableIPv6”: false,
“IPAM”: {
“Driver”: “default”,
“Options”: null,
“Config”: [
{
“Subnet”: “172.17.0.0/16”,
“Gateway”: “172.17.0.1”
}
]
},
“Internal”: false,
“Attachable”: false,
“Ingress”: false,
“ConfigFrom”: {
“Network”: “”
},
“ConfigOnly”: false,
“Containers”: {
“0145aa8906d9e62823e091c3fbcfbce50bc27b27224f2cca456182d0dc52d9bc”: {
“Name”: “my-mongo”,
“EndpointID”: “829f503daadc5a23b401ae20a0825d920a01d15a6d426692aa7072937a4d9b16”,
“MacAddress”: “02:42:ac:11:00:03”,
“IPv4Address”: “172.17.0.3/16”,
“IPv6Address”: “”
},
“557b896ff138395489dfa2cf327366fe6e8d17baf72eb0d09bbeade4ee5eee5b”: {
“Name”: “my-site”,
“EndpointID”: “036f11da0b3d5c3da9f69f9a04569422d9e7d57b98eb920fc1cd046c1951d616”,
“MacAddress”: “02:42:ac:11:00:02”,
“IPv4Address”: “172.17.0.2/16”,
“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”: {}
}
]
(2) 建立一個bridge，名字為samle-net
[root@c720120 ~]# docker network create –driver bridge sample-net
b4b881419620c448a18ec5aa1a09d8945b657a19a74c250f843311c62b3cb1da
(3) 檢查建立的sample-net bridge相關的subnet資訊
[root@c720120 ~]# docker network inspect sample-net | grep Subnet
“Subnet”: “172.20.0.0/16”,
(4) 建立bridge，並指定分配的子網資訊。
[root@c720120 ~]# docker network create –driver bridge –subnet “10.1.0.0/16” test-net
92377dbb1f7d74382a017c624f7b8ba83543c53f56ef2d835e3932b0d6cdfbfe
2. 關聯birdge到指定的容器上，案例如下
（1）建立一個容器，名字為c1。網路使用預設的
[root@c720120 ~]# docker container run –name c1 -it –rm alpine:latest /bin/sh
/ #
（2）檢查容器C1的網路設定
“NetworkSettings”: {
“Bridge”: “”,
“SandboxID”: “4c6dddcd6563b82fcf1e6c4360996a1fc183417224af2f82b1cf75b33a127cb5”,
“HairpinMode”: false,
“LinkLocalIPv6Address”: “”,
“LinkLocalIPv6PrefixLen”: 0,
“Ports”: {},
“SandboxKey”: “/var/run/docker/netns/4c6dddcd6563”,
“SecondaryIPAddresses”: null,
“SecondaryIPv6Addresses”: null,
“EndpointID”: “e9e70391b5a812e5237d29390a62dd9ad30229f5a952868cb05f406261ea9d38”,
“Gateway”: “172.17.0.1”,
“GlobalIPv6Address”: “”,
“GlobalIPv6PrefixLen”: 0,
“IPAddress”: “172.17.0.4”,
“IPPrefixLen”: 16,
“IPv6Gateway”: “”,
“MacAddress”: “02:42:ac:11:00:04”,
“Networks”: {
“bridge”: {
“IPAMConfig”: null,
“Links”: null,
“Aliases”: null,
“NetworkID”: “8d4ce133354ba6e3ab01684cf18b88535230647e78a6d698f1ef8d79f767b169”,
“EndpointID”: “e9e70391b5a812e5237d29390a62dd9ad30229f5a952868cb05f406261ea9d38”,
“Gateway”: “172.17.0.1”,
“IPAddress”: “172.17.0.4”,
“IPPrefixLen”: 16,
“IPv6Gateway”: “”,
“GlobalIPv6Address”: “”,
“GlobalIPv6PrefixLen”: 0,
“MacAddress”: “02:42:ac:11:00:04”,
“DriverOpts”: null
}
（3）在容器內部檢查IP地址
/ # ip addr
1: 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
92: eth0@if93: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP
link/ether 02:42:ac:11:00:04 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.4/16 brd 172.17.255.255 scope global eth0
valid_lft forever preferred_lft forever
（4）在容器內部檢查route資訊
default via 172.17.0.1 dev eth0
172.17.0.0/16 dev eth0 scope link src 172.17.0.4
（5）執行容器C2
[root@c720120 ~]# docker container run –name c2 -d alpine:latest ping 127.0.0.1
6771f308f6df35fd7f8335d80f001fdb4c71090e8a5dd928d385a3003c044470
（6）檢查容器C2網路的IP地址
[root@c720120 ~]# docker container inspect –format “{{.NetworkSettings.IPAddress}}” c2
172.17.0.5
（7）再次檢查橋的資訊
“63ea128f076aa697e425eba4c7ca485d73c39f4d08d4a25d300372d00fec87c8”: {
“Name”: “c1”,
“EndpointID”: “e9e70391b5a812e5237d29390a62dd9ad30229f5a952868cb05f406261ea9d38”,
“MacAddress”: “02:42:ac:11:00:04”,
“IPv4Address”: “172.17.0.4/16”,
“IPv6Address”: “”
},
“6771f308f6df35fd7f8335d80f001fdb4c71090e8a5dd928d385a3003c044470”: {
“Name”: “c2”,
“EndpointID”: “d7bee7887e97cdb0a4fa9d32bc30c8db0f0aaf6385dd4aa37f61db3557266b98”,
“MacAddress”: “02:42:ac:11:00:05”,
“IPv4Address”: “172.17.0.5/16”,
“IPv6Address”: “”
}
（8）建立 c3和c4容器，並指定網路為我們建立的橋test-net.
[root@c720120 ~]# docker container run –name c3 -d –network test-net
> alpine:latest ping 127.0.0.1
b7273876aa8880e285ddb566e5cdf08dd64fbfd4be2223c7277263976c22d1d5
[root@c720120 ~]# docker container run –name c4 -d –network test-net
> alpine:latest ping 127.0.0.1
27aa55af5c781e6b522c6d26c9e4ed8abcba8bf5c3f7378595a7863ccebe50cd
(9) 檢查橋test-net資訊
[root@c720120 ~]# docker network inspect test-net
[
{
“Name”: “test-net”,
“Id”: “92377dbb1f7d74382a017c624f7b8ba83543c53f56ef2d835e3932b0d6cdfbfe”,
“Created”: “2018-06-06T10:29:52.724830511+08:00”,
“Scope”: “local”,
“Driver”: “bridge”,
“EnableIPv6”: false,
“IPAM”: {
“Driver”: “default”,
“Options”: {},
“Config”: [
{
“Subnet”: “10.1.0.0/16”
}
]
},
“Internal”: false,
“Attachable”: false,
“Ingress”: false,
“ConfigFrom”: {
“Network”: “”
},
“ConfigOnly”: false,
“Containers”: {
“27aa55af5c781e6b522c6d26c9e4ed8abcba8bf5c3f7378595a7863ccebe50cd”: {
“Name”: “c4”,
“EndpointID”: “f0b67945ac99fa496b592a2d589d611e7d804007d18d81fc7690e633edaa5588”,
“MacAddress”: “02:42:0a:01:00:03”,
“IPv4Address”: “10.1.0.3/16”,
“IPv6Address”: “”
},
“b7273876aa8880e285ddb566e5cdf08dd64fbfd4be2223c7277263976c22d1d5”: {
“Name”: “c3”,
“EndpointID”: “2928052cf121f4511356ae4ddc5c7fb2b7cef7781f108b56ec31484f9fa1afa1”,
“MacAddress”: “02:42:0a:01:00:02”,
“IPv4Address”: “10.1.0.2/16”,
“IPv6Address”: “”
}
},
“Options”: {},
“Labels”: {}
}
]
（10） 進入到c3容器
[root@c720120 ~]# docker container exec -it c3 /bin/sh
（11）檢查到c4的網路是否可以互通。
/ # ping c4
PING c4 (10.1.0.3): 56 data bytes
64 bytes from 10.1.0.3: seq=0 ttl=64 time=0.371 ms
64 bytes from 10.1.0.3: seq=1 ttl=64 time=0.159 ms
64 bytes from 10.1.0.3: seq=2 ttl=64 time=0.183 ms
64 bytes from 10.1.0.3: seq=3 ttl=64 time=0.181 ms
（12）檢查到c2的網路是否可以互通。
/ # ping c2
ping: bad address `c2`
結論：關聯到相同的橋網路可以互相通訊，不同橋之間是無法通訊的，且bridge的作用範圍僅限本機。
（13）移除建立的橋網路
[root@c720120 ~]# docker network rm test-net
Error response from daemon: network test-net id 92377dbb1f7d74382a017c624f7b8ba83543c53f56ef2d835e3932b0d6cdfbfe has active endpoints
注意：如果建立的橋被其它容器正在引用，無法刪除，需要先刪除關聯的容器，再刪除相關的橋。
（14）刪除容器
[root@c720120 ~]# dockere container rm -f $(docker container ls -aq)
（15）刪除建立的橋
[root@c720120 ~]# docker network rm sample-net
[root@c720120 ~]# docker network rm test-net
三. The host network
1. 關聯docker host網路，執行以下指令
[root@c720120 ~]# docker container run –rm -it –network host alpine:latest /bin/sh
2. 在容器內部檢視網路資訊
/ # ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 52:54:00:da:66:d3 brd ff:ff:ff:ff:ff:ff
inet 192.168.20.120/24 brd 192.168.20.255 scope global eth0
3. 在容器內部檢視路由資訊
/ # ip route
default via 192.168.20.1 dev eth0 metric 100
10.1.0.0/16 dev br-92377dbb1f7d scope link src 10.1.0.1
10.244.0.0/24 dev cni0 scope link src 10.244.0.1
10.244.1.0/24 via 10.244.1.0 dev flannel.1 onlink
10.244.2.0/24 via 10.244.2.0 dev flannel.1 onlink
10.244.3.0/24 via 10.244.3.0 dev flannel.1 onlink
10.244.4.0/24 via 10.244.4.0 dev flannel.1 onlink
172.17.0.0/16 dev docker0 scope link src 172.17.0.1
172.18.0.0/16 dev br-4d8fecd89ea0 scope link src 172.18.0.1
172.19.0.0/16 dev docker_gwbridge scope link src 172.19.0.1
172.20.0.0/16 dev br-b4b881419620 scope link src 172.20.0.1
192.168.20.0/24 dev eth0 scope link src 192.168.20.120 metric 100
四. The null network
1. 關聯null網路，執行以下命令
[root@c720120 ~]# docker container run –rm -it –network none alpine:latest /bin/sh
/ #
2. 在容器內部檢視IP地址資訊
/ # ip addr show eth0
ip: can`t find device `eth0`
3. 在容器內部檢視路由資訊
/ # ip route
五. 執行在一個已經存在的網路名稱空間
執行多個容器在單 一網路全名空間如下：
1. 建立網路橋，名字為test-net
[root@c720120 ~]# docker network create –driver bridge test-net
2. 執行一個容器，並關聯到橋test-net
[root@c720120 ~]# docker container run –name web -d –network test-net nginx:alpine
ead5f17f047e47fedca5d54ebcfea729aa12c5be2776e3b2868f01f2330658f9
3. 執行另外一個容器，網路使用第2步建立的容器的網路名稱空間。
[root@c720120 ~]# docker container run -it –rm –network container:web alpine:latest /bin/sh
/ #
4.測試 localhost是否可以訪問web容器中的內容
/ # wget -qO – localhost
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p><p>For online documentation and support please refer to
<a href=”http://nginx.org/”>nginx.org</a>.<br/>
Commercial support is available at
<a href=”http://nginx.com/”>nginx.com</a>.</p><p><em>Thank you for using nginx.</em></p>
</body>Next Section
</html>
5. 刪除建立的容器和網路（實驗結束）
[root@c720120 ~]# docker container rm –force web
web[root@c720120 ~]# docker network rm test-net
六. 埠管理
1. 埠對映
（1）埠對映（一個隨機的32xxx埠）
[root@c720120 ~]# docker container run –name web -P -d nginx:alpine
78e5086b7e0ad6f1283dff7485f74f27c492b1d8a96f602e9937fd8e0bcf96f4
（2）檢視對映的埠
[root@c720120 ~]# docker container port web
80/tcp -> 0.0.0.0:32768
也可以通過下列方式檢視埠對映關係：
[root@c720120 ~]# docker container inspect web | grep HostPort
“HostPort”: “32768”
或者：
[root@c720120 ~]# docker container ls
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
78e5086b7e0a nginx:alpine “nginx -g `daemon of…” 2 minutes ago Up 2 minutes 0.0.0.0:32768->80/tcp web
（3）手工指定要對映的埠（不隨機分配 ）
[root@c720120 ~]# docker container run –name web2 -p 8080:80 -d nginx:alpine
f8e6775b9c2537094a8e811c9fd927cd918436676e7d5d4a39482262f40770d9