Docker 容器网络，主要采用架构由三部分组成：CNM、Libnetwork、驱动。
CNM ：
? ? Docker网络采用的设计规范时CNM(Container Network Model) : ?CNM规定了Docker网络的基础组成要素：Sandbox、Endpoint、Network。
? ? 容器包含 Endpoint 和 Sandbox 而 Sandbox 包含 Endpoint 然后 Endpoint 和 Network 对接
。Sandbox：提供了容器的虚拟网络栈，也即端口套接字、IP路由表、防火墙、DNS配置等内容。 主要用于隔离容器网络与宿主机网络，形成了完成独立的容器网络环境。
。Network，Docker内部的虚拟子网，网络内的参与者相互可见并能够进行通讯。 Docker的虚拟网路和宿主机网络存在隔离关系，主要目的是形成容器间的安全通讯环境。
。Endpoint，主要负责创建连接，
?? ?
Libetwork
? ? 是CNM 的标准实行，Libnetwork（Go语言开发）实现了CNM中定义的全部三个组件，此外它还实现了本地服务发现、基于Ingress容器负载均衡，以及网络控制层和管理层功能。
驱动
? ? 如果说Libnetwork实现控制层和管理层功能，那么
驱动 就负责实现数据层。 驱动通过实现特定网络类型的方式扩展了Docker网络栈，例入桥接网络和覆盖网络。
? ? Docker内置了诺干驱动，通常被称为原生驱动或者本地驱动。比如Bridge Driver、Host Driver、Overlay Driver、MacLan Driver、None Driver等等。 第三方也可以编写Docker 网络驱动，这些驱动被叫做远程驱动，例入Calico、Contiv、Kuryr 以及Weave。每个驱动负责创建其上所有网络资源的创建和管理。
其中 Bridge 和 Overlay 在开发过程中使用频率较高
。Bridge，Docker容器的默认网络驱动，通过网桥来实现网络通讯。
。Overlay，借助 Docker 集群模块 Docker Swarm 搭建的跨 Docker Daemon 网络。
?? ?
Docker安装时，会自动安装一块Docker 网卡称为 docker0
$ ifconfig
?
docker0: flags=4099<UP,BROADCAST,MULTICAST>??mtu 1500
????????inet 172.17.0.1??netmask 255.255.0.0??broadcast 0.0.0.0
????????inet6 fe80::42:23ff:feab:dd7e??prefixlen 64??scopeid 0x20<link>
????????ether 02:42:23:ab:dd:7e??txqueuelen 0??(Ethernet)
????????RX packets 6??bytes 452 (452.0 B)
????????RX errors 0??dropped 0??overruns 0??frame 0
????????TX packets 5??bytes 450 (450.0 B)
????????TX errors 0??dropped 0 overruns 0??carrier 0??collisions 02.桥接网络
? ? Docker 的bridge 网络采用内置的bridge驱动，而bridge的底层采用的是Linux内核中 Linux bridge技术。
? ? 容器间的通信 bridge：
一、创建两个容器
$?docker container run -d --rm --name box1 busybox /bin/sh -c "while true; do sleep 3600; done”
Unable to find image 'busybox:latest' locally
Trying to pull repository docker.io/library/busybox ...
latest: Pulling from docker.io/library/busybox
7e5209d2300f: Pull complete
Digest: sha256:34c3559bbdedefd67195e766e38cfbb0fcabff4241dbee3f390fd6e3310f5ebc
Status: Downloaded newer image for docker.io/busybox:latest
019a0daed76f2c71ccb7879a259cc04eac9b60a826529c383f104ffa1ad12f3d
$?docker container run -d --rm --name box2 busybox /bin/sh -c "while true; do sleep 3600; done"
3325eedba7c2b16956b20d1eea968c74471e0fb42747fb73079f74bae460e16c
? ? 查看容器
$?docker container ls
CONTAINER ID????????IMAGE???????????????COMMAND??????????????????CREATED?????????????STATUS??????????????PORTS???????????????NAMES
3325eedba7c2????????busybox?????????????"/bin/sh -c 'while..."???7 seconds ago???????Up 6 seconds????????????????????????????box2
019a0daed76f????????busybox?????????????"/bin/sh -c 'while..."???14 seconds ago??????Up 13 seconds???????????????????????????box1
$?docker network ls
NETWORK ID??????????NAME????????????????DRIVER??????????????SCOPE
48bcb226d17e????????bridge??????????????bridge??????????????local
3ea7c9283722????????host????????????????host????????????????local
eee2e5b9cf19????????none????????????????null????????????????local
$ docker network inspect bridge
[
????{
????????"Name": "bridge",
????????"Id": "48bcb226d17e09092378deb2c4e9a070edb64f5bc6e0b0378edd45f5f248a6f2",
????????"Created": "2022-03-04T18:00:02.632533487+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,
????????"Containers": {
????????????"019a0daed76f2c71ccb7879a259cc04eac9b60a826529c383f104ffa1ad12f3d": {
????????????????"Name": "box1",
????????????????"EndpointID": "8d09e83384eeeb6cb9fc31fadb1d9f39339ae4ccd6971dc790f60410797c6a07",
????????????????"MacAddress": "02:42:ac:11:00:02",
????????????????"IPv4Address": "172.17.0.2/16",
????????????????"IPv6Address": ""
????????????},
????????????"3325eedba7c2b16956b20d1eea968c74471e0fb42747fb73079f74bae460e16c": {
????????????????"Name": "box2",
????????????????"EndpointID": "52c096c53b562a205a8880417cbba8fe0ff0fb1c0cbf3fd7fa67f828fbd72ac4",
????????????????"MacAddress": "02:42:ac:11:00:03",
????????????????"IPv4Address": "172.17.0.3/16",
????????????????"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": {}
????}
]
从此可以看出，两个容器都在一个叫docker0的Linux bridge上面，而docker0是docker默认安装添加上去的,可以证明：
容器相互之间可以拼通的。
而默认的 bridge网络是被映射到内核中为 docker0的 网桥上。
$?ip link show docker0
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default
????link/ether 02:42:23:ab:dd:7e brd ff:ff:ff:ff:ff:ff
Note: 你就可以把 bridge 和 docker0 当成 Linux 网桥的两个名字，两个都是代表同一个东西。docker 为了管理网络，又给 docker0 这个网桥取名为 bridge
Node:也可以通过 brctl 命令进行 bridge 连接接口查看（
brctl
?使用前需要安装, 对于CentOS, 可以通过?
sudo?
yum?
install?
-y?
bridge-utils
?安装. 对于Ubuntu, 可以通过?
sudo?
apt-get?
install?
-y?
bridge-utils
）
$?brctl show
bridge name????bridge id????????STP enabled????interfaces
docker0????????8000.024223abdd7e????no????????veth33f963f
?????????????????????????????? ??? ??? ??? ?? vethceb182f
从上面也可以确认两个接口进行通信。
2、容器对外通信
一、 查看路由
$ ip route
default via 172.19.79.253 dev eth0
169.254.0.0/16 dev eth0 scope link metric 1002
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1
172.19.64.0/20 dev eth0 proto kernel scope link src 172.19.77.225
(个人理解：从此可以看出，如果是其他应用访问走的默认，如果docker就会走docker0接口，而经过桥接docker0其实意义上可以说是eth0 所以容器是可以访问外网。这里里面不得不提iptables转发)
二、端口转发
命令通过
-p
$ docker container run -d --rm --name -p8080:80 web nginx
?? ?
效果
http://我的IP地址:8080/
端口映射
? ? 如上效果图所示，容器内部开放端口为 80 ，该端口映射到了Docker主机的8080端口上，最终访问上面的IP地址所有流量都会转发到容器的80端口上面。
通过iptables命令可以更直观的感受
$?iptables -t nat -nvxL
Chain PREROUTING (policy ACCEPT 3 packets, 112 bytes)
????pkts??????bytes target?????prot opt in?????out?????source???????????????destination?????????
????8398???514593 DOCKER?????all??--??*??????*???????0.0.0.0/0????????????0.0.0.0/0????????????ADDRTYPE match dst-type LOCAL
Chain INPUT (policy ACCEPT 3 packets, 112 bytes)
????pkts??????bytes target?????prot opt in?????out?????source???????????????destination?????????
Chain OUTPUT (policy ACCEPT 33 packets, 2300 bytes)
????pkts??????bytes target?????prot opt in?????out?????source???????????????destination?????????
???????0????????0 DOCKER?????all??--??*??????*???????0.0.0.0/0???????????!127.0.0.0/8??????????ADDRTYPE match dst-type LOCAL
Chain POSTROUTING (policy ACCEPT 35 packets, 2428 bytes)
????pkts??????bytes target?????prot opt in?????out?????source???????????????destination?????????
???????0????????0 MASQUERADE??all??--??*??????!br-43435188760c??172.18.0.0/16????????0.0.0.0/0???????????
???????0????????0 MASQUERADE??all??--??*??????!docker0??172.17.0.0/16????????0.0.0.0/0???????????
???????0????????0 MASQUERADE??tcp??--??*??????*???????172.17.0.4???????????172.17.0.4???????????tcp dpt:80
Chain DOCKER (2 references)
????pkts??????bytes target?????prot opt in?????out?????source???????????????destination?????????
???????0????????0 RETURN?????all??--??br-43435188760c *???????0.0.0.0/0????????????0.0.0.0/0???????????
???????0????????0 RETURN?????all??--??docker0 *???????0.0.0.0/0????????????0.0.0.0/0???????????
???????2??????128 DNAT???????tcp??--??!docker0 *???????0.0.0.0/0????????????0.0.0.0/0????????????tcp dpt:8080 to:172.17.0.4:80
? ? tcp dpt:8080 to :172.17.0.4:80 刚刚好对应上面的效果。
3、自定义桥接bridge
$? docker network create -d bridge mybridge
43435188760ce70d58099ab5fe27b85fc07e2f5e14d6748e6532daa5749d4963
$?docker network ls
NETWORK ID??????????NAME????????????????DRIVER??????????????SCOPE
48bcb226d17e????????bridge??????????????bridge??????????????local
3ea7c9283722????????host????????????????host????????????????local
43435188760c????????mybridge????????????bridge??????????????local
eee2e5b9cf19????????none????????????????null????????????????local
$? docker network inspect mybridge
[
????{
????????"Name": "mybridge",
????????"Id": "43435188760ce70d58099ab5fe27b85fc07e2f5e14d6748e6532daa5749d4963",
????????"Created": "2022-03-07T15:41:06.440007809+08:00",
????????"Scope": "local",
????????"Driver": "bridge",
????????"EnableIPv6": false,
????????"IPAM": {
????????????"Driver": "default",
????????????"Options": {},
????????????"Config": [
????????????????{
????????????????????"Subnet": "172.18.0.0/16",
????????????????????"Gateway": "172.18.0.1"
????????????????}
????????????]
????????},
????????"Internal": false,
????????"Attachable": false,
????????"Containers": {},
????????"Options": {},
????????"Labels": {}
????}
]
$? docker container run -d --rm --name box3 --network mybridge??busybox /bin/sh -c "while true; do sleep 3600; done”
2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719
$?docker container ls
CONTAINER ID????????IMAGE???????????????COMMAND??????????????????CREATED?????????????STATUS??????????????PORTS???????????????NAMES
2d7ce63d7e3f????????busybox?????????????"/bin/sh -c 'while..."???9 seconds ago???????Up 8 seconds????????????????????????????box3
3325eedba7c2????????busybox?????????????"/bin/sh -c 'while..."???2 hours ago?????????Up 2 hours??????????????????????????????box2
019a0daed76f????????busybox?????????????"/bin/sh -c 'while..."???2 hours ago?????????Up 2 hours??????????????????????????????box1
$?docker container inspect box3
[
????{
????????"Id": "2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719",
????????"Created": "2022-03-07T07:44:18.269363219Z",
????????"Path": "/bin/sh",
????????"Args": [
????????????"-c",
????????????"while true; do sleep 3600; done"
????????],
????????"State": {
????????????"Status": "running",
????????????"Running": true,
????????????"Paused": false,
????????????"Restarting": false,
????????????"OOMKilled": false,
????????????"Dead": false,
????????????"Pid": 6911,
????????????"ExitCode": 0,
????????????"Error": "",
????????????"StartedAt": "2022-03-07T07:44:18.567776199Z",
????????????"FinishedAt": "0001-01-01T00:00:00Z"
????????},
????????"Image": "sha256:829374d342ae65a12f3a95911bc04a001894349f70783fda841b1a784008727d",
????????"ResolvConfPath": "/var/lib/docker/containers/2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719/resolv.conf",
????????"HostnamePath": "/var/lib/docker/containers/2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719/hostname",
????????"HostsPath": "/var/lib/docker/containers/2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719/hosts",
????????"LogPath": "",
????????"Name": "/box3",
????????"RestartCount": 0,
????????"Driver": "overlay2",
????????"MountLabel": "",
????????"ProcessLabel": "",
????????"AppArmorProfile": "",
????????"ExecIDs": null,
????????"HostConfig": {
????????????"Binds": null,
????????????"ContainerIDFile": "",
????????????"LogConfig": {
????????????????"Type": "journald",
????????????????"Config": {}
????????????},
????????????"NetworkMode": "mybridge",
????????????"PortBindings": {},
????????????"RestartPolicy": {
????????????????"Name": "no",
????????????????"MaximumRetryCount": 0
????????????},
????????????"AutoRemove": true,
????????????"VolumeDriver": "",
????????????"VolumesFrom": null,
????????????"CapAdd": null,
????????????"CapDrop": null,
????????????"Dns": [],
????????????"DnsOptions": [],
????????????"DnsSearch": [],
????????????"ExtraHosts": null,
????????????"GroupAdd": null,
????????????"IpcMode": "",
????????????"Cgroup": "",
????????????"Links": null,
????????????"OomScoreAdj": 0,
????????????"PidMode": "",
????????????"Privileged": false,
????????????"PublishAllPorts": false,
????????????"ReadonlyRootfs": false,
????????????"SecurityOpt": null,
????????????"UTSMode": "",
????????????"UsernsMode": "",
????????????"ShmSize": 67108864,
????????????"Runtime": "docker-runc",
????????????"ConsoleSize": [
????????????????0,
????????????????0
????????????],
????????????"Isolation": "",
????????????"CpuShares": 0,
????????????"Memory": 0,
????????????"NanoCpus": 0,
????????????"CgroupParent": "",
????????????"BlkioWeight": 0,
????????????"BlkioWeightDevice": null,
????????????"BlkioDeviceReadBps": null,
????????????"BlkioDeviceWriteBps": null,
????????????"BlkioDeviceReadIOps": null,
????????????"BlkioDeviceWriteIOps": null,
????????????"CpuPeriod": 0,
????????????"CpuQuota": 0,
????????????"CpuRealtimePeriod": 0,
????????????"CpuRealtimeRuntime": 0,
????????????"CpusetCpus": "",
????????????"CpusetMems": "",
????????????"Devices": [],
????????????"DiskQuota": 0,
????????????"KernelMemory": 0,
????????????"MemoryReservation": 0,
????????????"MemorySwap": 0,
????????????"MemorySwappiness": -1,
????????????"OomKillDisable": false,
????????????"PidsLimit": 0,
????????????"Ulimits": null,
????????????"CpuCount": 0,
????????????"CpuPercent": 0,
????????????"IOMaximumIOps": 0,
????????????"IOMaximumBandwidth": 0
????????},
????????"GraphDriver": {
????????????"Name": "overlay2",
????????????"Data": {
????????????????"LowerDir": "/var/lib/docker/overlay2/fba5480131b3e84ac8abfa7905de44c4049dbe627139833b40ce38c39dcf8eb6-init/diff:/var/lib/docker/overlay2/98edee56f7a26a7781c93c13d5bbef9bbb9e8f32ad3c37201bc45c00bfb5a0a6/diff",
????????????????"MergedDir": "/var/lib/docker/overlay2/fba5480131b3e84ac8abfa7905de44c4049dbe627139833b40ce38c39dcf8eb6/merged",
????????????????"UpperDir": "/var/lib/docker/overlay2/fba5480131b3e84ac8abfa7905de44c4049dbe627139833b40ce38c39dcf8eb6/diff",
????????????????"WorkDir": "/var/lib/docker/overlay2/fba5480131b3e84ac8abfa7905de44c4049dbe627139833b40ce38c39dcf8eb6/work"
????????????}
????????},
????????"Mounts": [],
????????"Config": {
????????????"Hostname": "2d7ce63d7e3f",
????????????"Domainname": "",
????????????"User": "",
????????????"AttachStdin": false,
????????????"AttachStdout": false,
????????????"AttachStderr": false,
????????????"Tty": false,
????????????"OpenStdin": false,
????????????"StdinOnce": false,
????????????"Env": [
????????????????"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
????????????],
????????????"Cmd": [
????????????????"/bin/sh",
????????????????"-c",
????????????????"while true; do sleep 3600; done"
????????????],
????????????"Image": "busybox",
????????????"Volumes": null,
????????????"WorkingDir": "",
????????????"Entrypoint": null,
????????????"OnBuild": null,
????????????"Labels": {}
????????},
????????"NetworkSettings": {
????????????"Bridge": "",
????????????"SandboxID": "f967524cdbe0c5a0d70da4a45cde98bc250c28467678d7fe6de8fb38485d9788",
????????????"HairpinMode": false,
????????????"LinkLocalIPv6Address": "",
????????????"LinkLocalIPv6PrefixLen": 0,
????????????"Ports": {},
????????????"SandboxKey": "/var/run/docker/netns/f967524cdbe0",
????????????"SecondaryIPAddresses": null,
????????????"SecondaryIPv6Addresses": null,
????????????"EndpointID": "",
????????????"Gateway": "",
????????????"GlobalIPv6Address": "",
????????????"GlobalIPv6PrefixLen": 0,
????????????"IPAddress": "",
????????????"IPPrefixLen": 0,
????????????"IPv6Gateway": "",
????????????"MacAddress": "",
????????????"Networks": {
????????????????"mybridge": {
????????????????????"IPAMConfig": null,
????????????????????"Links": null,
????????????????????"Aliases": [
????????????????????????"2d7ce63d7e3f"
????????????????????],
????????????????????"NetworkID": "43435188760ce70d58099ab5fe27b85fc07e2f5e14d6748e6532daa5749d4963",
????????????????????"EndpointID": "0e2fa562b7f2050eb84114356ac9882dbac340a675a32036b14040c0db35b035",
????????????????????"Gateway": "172.18.0.1",
????????????????????"IPAddress": "172.18.0.2",
????????????????????"IPPrefixLen": 16,
????????????????????"IPv6Gateway": "",
????????????????????"GlobalIPv6Address": "",
????????????????????"GlobalIPv6PrefixLen": 0,
????????????????????"MacAddress": "02:42:ac:12:00:02"
????????????????}
????????????}
????????}
????}
]
$? docker network inspect mybridge
[
????{
????????"Name": "mybridge",
????????"Id": "43435188760ce70d58099ab5fe27b85fc07e2f5e14d6748e6532daa5749d4963",
????????"Created": "2022-03-07T15:41:06.440007809+08:00",
????????"Scope": "local",
????????"Driver": "bridge",
????????"EnableIPv6": false,
????????"IPAM": {
????????????"Driver": "default",
????????????"Options": {},
????????????"Config": [
????????????????{
????????????????????"Subnet": "172.18.0.0/16",
????????????????????"Gateway": "172.18.0.1"
????????????????}
????????????]
????????},
????????"Internal": false,
????????"Attachable": false,
????????"Containers": {
????????????"2d7ce63d7e3f956564e684e343b7da2ae747e5679292c109096f619e73bce719": {
????????????????"Name": "box3",
????????????????"EndpointID": "0e2fa562b7f2050eb84114356ac9882dbac340a675a32036b14040c0db35b035",
????????????????"MacAddress": "02:42:ac:12:00:02",
????????????????"IPv4Address": "172.18.0.2/16",
????????????????"IPv6Address": ""
????????????}
????????},
????????"Options": {},
????????"Labels": {}
????}
]
通过上面操作就是已经建立好了自己的容器且指向自己创建的桥接。
记录上面没有使用过的命令
//容器连接第二个bridge
$ docker network connect bridge box3
//进入到容器 sh 里面
$ docker container exec -it box3 sh
//断开容器 bridge 连接
$ docker network disconnect bridge box3
//创建网络参数
$?docker network create —help
Usage:????docker network create [OPTIONS] NETWORK
Create a network
Options:
??????--attachable?????????????Enable manual container attachment
??????--aux-address map????????Auxiliary IPv4 or IPv6 addresses used by Network driver (default map[])
??-d, --driver string??????????Driver to manage the Network (default "bridge")
??????--gateway stringSlice????IPv4 or IPv6 Gateway for the master subnet
??????--help???????????????????Print usage
??????--internal???????????????Restrict external access to the network
??????--ip-range stringSlice???Allocate container ip from a sub-range
??????--ipam-driver string?????IP Address Management Driver (default "default")
??????--ipam-opt map???????????Set IPAM driver specific options (default map[])
??????--ipv6???????????????????Enable IPv6 networking
??????--label list?????????????Set metadata on a network (default [])
??-o, --opt map????????????????Set driver specific options (default map[])
??????--subnet stringSlice?????Subnet in CIDR format that represents a network segment
//网络配置
$?docker container inspect --format '{{.NetworkSettings.IPAddress}}’ box2
172.17.0.3
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