使用独立容器进行网络连接
本系列教程涉及独立 Docker 容器的网络。 关于 swarm 服务的网络，请参阅 Swarm 服务的网络。如果您需要 了解更多关于 Docker 网络的一般信息，请参阅 概述。
本主题包含两个不同的教程。您可以在 Linux、Windows 或 Mac 上运行它们，但对于最后一个教程，您需要在其他地方运行第二个 Docker 主机。
使用默认桥接网络 演示了如何使用 Docker 自动为您设置的默认
bridge网络。该网络不是生产系统的最佳选择。使用用户定义的桥接网络 展示了 如何创建和使用您自己的自定义桥接网络，以连接运行在同一个 Docker 主机上的容器。这适用于在生产环境中运行的独立容器。
虽然 overlay networks 通常用于 swarm 服务， 但您也可以将 overlay 网络用于独立容器。这已包含在 overlay 网络使用教程 中。
使用默认桥接网络
在本示例中，您将在同一 Docker 主机上启动两个不同的 alpine 容器，并进行一些测试以了解它们如何相互通信。您需要安装并运行 Docker。
打开终端窗口。在执行其他操作之前，先列出当前的网络。 如果您从未在此 Docker 守护进程上添加网络或初始化过 swarm，您应该会看到以下内容。您可能会看到不同的网络，但至少应该看到这些（网络 ID 会不同）：
$ docker network ls NETWORK ID NAME DRIVER SCOPE 17e324f45964 bridge bridge local 6ed54d316334 host host local 7092879f2cc8 none null local默认的
bridge网络已列出，以及host和none。后两者并非完整的网络，而是用于启动一个直接连接到 Docker 守护进程主机网络栈的容器，或启动一个没有网络设备的容器。本教程将把两个容器连接到bridge网络。启动两个运行
alpine的ash容器，这是 Alpine 的默认 shell，而不是bash。-dit标志表示以分离模式（在后台）、交互式（可以输入）和 TTY（可以看到输入和输出）启动容器。由于您是以分离模式启动它，因此不会立即连接到容器。相反，会打印容器的 ID。因为您没有指定任何--network标志，所以容器连接到默认的bridge网络。$ docker run -dit --name alpine1 alpine ash $ docker run -dit --name alpine2 alpine ash检查两个容器是否确实已启动：
$ docker container ls CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 602dbf1edc81 alpine "ash" 4 seconds ago Up 3 seconds alpine2 da33b7aa74b0 alpine "ash" 17 seconds ago Up 16 seconds alpine1检查
bridge网络，查看有哪些容器连接到它。$ docker network inspect bridge [ { "Name": "bridge", "Id": "17e324f459648a9baaea32b248d3884da102dde19396c25b30ec800068ce6b10", "Created": "2017-06-22T20:27:43.826654485Z", "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": { "602dbf1edc81813304b6cf0a647e65333dc6fe6ee6ed572dc0f686a3307c6a2c": { "Name": "alpine2", "EndpointID": "03b6aafb7ca4d7e531e292901b43719c0e34cc7eef565b38a6bf84acf50f38cd", "MacAddress": "02:42:ac:11:00:03", "IPv4Address": "172.17.0.3/16", "IPv6Address": "" }, "da33b7aa74b0bf3bda3ebd502d404320ca112a268aafe05b4851d1e3312ed168": { "Name": "alpine1", "EndpointID": "46c044a645d6afc42ddd7857d19e9dcfb89ad790afb5c239a35ac0af5e8a5bc5", "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": {} } ]靠近顶部，列出了关于
bridge网络的信息，包括 Docker 主机和bridge网络之间网关的 IP 地址（172.17.0.1）。在Containers键下，列出了每个连接的容器，以及关于其 IP 地址的信息（172.17.0.2用于alpine1，172.17.0.3用于alpine2）。容器正在后台运行。使用
docker attach命令连接到alpine1。$ docker attach alpine1 / #提示符变为
#，表示您是容器内的root用户。使用ip addr show命令显示alpine1的网络接口，这些接口是从容器内部看到的：# ip addr show 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 27: eth0@if28: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff inet 172.17.0.2/16 scope global eth0 valid_lft forever preferred_lft forever inet6 fe80::42:acff:fe11:2/64 scope link valid_lft forever preferred_lft forever第一个接口是回环设备。现在暂时忽略它。请注意， 第二个接口的 IP 地址是
172.17.0.2，这与上一步中 显示的alpine1的地址相同。在
alpine1内部，确保可以通过 pinggoogle.com连接到互联网。-c 2标志将命令限制为两次ping尝试。# ping -c 2 google.com PING google.com (172.217.3.174): 56 data bytes 64 bytes from 172.217.3.174: seq=0 ttl=41 time=9.841 ms 64 bytes from 172.217.3.174: seq=1 ttl=41 time=9.897 ms --- google.com ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 9.841/9.869/9.897 ms现在尝试 ping 第二个容器。首先，通过其 IP 地址 ping 它，
172.17.0.3：# ping -c 2 172.17.0.3 PING 172.17.0.3 (172.17.0.3): 56 data bytes 64 bytes from 172.17.0.3: seq=0 ttl=64 time=0.086 ms 64 bytes from 172.17.0.3: seq=1 ttl=64 time=0.094 ms --- 172.17.0.3 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.086/0.090/0.094 ms成功了。接下来，尝试按容器名称 ping
alpine2容器。这将失败。# ping -c 2 alpine2 ping: bad address 'alpine2'在不停止容器的情况下，使用分离序列从
alpine1分离，CTRL+pCTRL+q（按住CTRL并依次输入p和q）。 如果需要，附加到alpine2并在那里重复步骤 4、5 和 6， 将alpine1替换为alpine2。停止并移除这两个容器。
$ docker container stop alpine1 alpine2 $ docker container rm alpine1 alpine2
请记住，默认的 bridge 网络不建议用于生产环境。要了解用户定义的桥接网络，请继续阅读
下一个教程。
使用用户自定义桥接网络
在此示例中，我们再次启动了两个 alpine 容器，但将它们连接到一个名为 alpine-net 的用户自定义网络，该网络我们已经创建。这些容器根本没有连接到默认的 bridge 网络。然后我们启动第三个 alpine 容器，它连接到 bridge 网络但不连接 alpine-net，以及第四个 alpine 容器，它连接到两个网络。
创建
alpine-net网络。您不需要--driver bridge标志，因为它是默认值，但此示例展示了如何指定它。$ docker network create --driver bridge alpine-net列出 Docker 的网络：
$ docker network ls NETWORK ID NAME DRIVER SCOPE e9261a8c9a19 alpine-net bridge local 17e324f45964 bridge bridge local 6ed54d316334 host host local 7092879f2cc8 none null local检查
alpine-net网络。这将显示它的 IP 地址以及没有容器连接到它的事实：$ docker network inspect alpine-net [ { "Name": "alpine-net", "Id": "e9261a8c9a19eabf2bf1488bf5f208b99b1608f330cff585c273d39481c9b0ec", "Created": "2017-09-25T21:38:12.620046142Z", "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": {} } ]请注意，该网络的网关是
172.18.0.1，这与默认的桥接网络不同，后者的网关是172.17.0.1。确切的 IP 地址在你的系统上可能会有所不同。创建您的四个容器。注意
--network标志。您在docker run命令期间只能连接到一个网络，因此您需要随后使用docker network connect将alpine4也连接到bridge网络。$ docker run -dit --name alpine1 --network alpine-net alpine ash $ docker run -dit --name alpine2 --network alpine-net alpine ash $ docker run -dit --name alpine3 alpine ash $ docker run -dit --name alpine4 --network alpine-net alpine ash $ docker network connect bridge alpine4验证所有容器是否正在运行：
$ docker container ls CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 156849ccd902 alpine "ash" 41 seconds ago Up 41 seconds alpine4 fa1340b8d83e alpine "ash" 51 seconds ago Up 51 seconds alpine3 a535d969081e alpine "ash" About a minute ago Up About a minute alpine2 0a02c449a6e9 alpine "ash" About a minute ago Up About a minute alpine1再次检查
bridge网络和alpine-net网络：$ docker network inspect bridge [ { "Name": "bridge", "Id": "17e324f459648a9baaea32b248d3884da102dde19396c25b30ec800068ce6b10", "Created": "2017-06-22T20:27:43.826654485Z", "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": { "156849ccd902b812b7d17f05d2d81532ccebe5bf788c9a79de63e12bb92fc621": { "Name": "alpine4", "EndpointID": "7277c5183f0da5148b33d05f329371fce7befc5282d2619cfb23690b2adf467d", "MacAddress": "02:42:ac:11:00:03", "IPv4Address": "172.17.0.3/16", "IPv6Address": "" }, "fa1340b8d83eef5497166951184ad3691eb48678a3664608ec448a687b047c53": { "Name": "alpine3", "EndpointID": "5ae767367dcbebc712c02d49556285e888819d4da6b69d88cd1b0d52a83af95f", "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": {} } ]容器
alpine3和alpine4已连接到bridge网络。$ docker network inspect alpine-net [ { "Name": "alpine-net", "Id": "e9261a8c9a19eabf2bf1488bf5f208b99b1608f330cff585c273d39481c9b0ec", "Created": "2017-09-25T21:38:12.620046142Z", "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": { "0a02c449a6e9a15113c51ab2681d72749548fb9f78fae4493e3b2e4e74199c4a": { "Name": "alpine1", "EndpointID": "c83621678eff9628f4e2d52baf82c49f974c36c05cba152db4c131e8e7a64673", "MacAddress": "02:42:ac:12:00:02", "IPv4Address": "172.18.0.2/16", "IPv6Address": "" }, "156849ccd902b812b7d17f05d2d81532ccebe5bf788c9a79de63e12bb92fc621": { "Name": "alpine4", "EndpointID": "058bc6a5e9272b532ef9a6ea6d7f3db4c37527ae2625d1cd1421580fd0731954", "MacAddress": "02:42:ac:12:00:04", "IPv4Address": "172.18.0.4/16", "IPv6Address": "" }, "a535d969081e003a149be8917631215616d9401edcb4d35d53f00e75ea1db653": { "Name": "alpine2", "EndpointID": "198f3141ccf2e7dba67bce358d7b71a07c5488e3867d8b7ad55a4c695ebb8740", "MacAddress": "02:42:ac:12:00:03", "IPv4Address": "172.18.0.3/16", "IPv6Address": "" } }, "Options": {}, "Labels": {} } ]容器
alpine1、alpine2和alpine4已连接到alpine-net网络。在像
alpine-net这样的用户自定义网络上，容器不仅可以 通过 IP 地址通信，还可以将容器名称解析为 IP 地址。这种功能称为自动服务发现。让我们 连接到alpine1并测试一下。alpine1应该能够解析alpine2和alpine4（以及alpine1，它自己）为 IP 地址。注意
自动服务发现只能解析自定义容器名称，而不能解析默认自动生成的容器名称，
$ docker container attach alpine1 # ping -c 2 alpine2 PING alpine2 (172.18.0.3): 56 data bytes 64 bytes from 172.18.0.3: seq=0 ttl=64 time=0.085 ms 64 bytes from 172.18.0.3: seq=1 ttl=64 time=0.090 ms --- alpine2 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.085/0.087/0.090 ms # ping -c 2 alpine4 PING alpine4 (172.18.0.4): 56 data bytes 64 bytes from 172.18.0.4: seq=0 ttl=64 time=0.076 ms 64 bytes from 172.18.0.4: seq=1 ttl=64 time=0.091 ms --- alpine4 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.076/0.083/0.091 ms # ping -c 2 alpine1 PING alpine1 (172.18.0.2): 56 data bytes 64 bytes from 172.18.0.2: seq=0 ttl=64 time=0.026 ms 64 bytes from 172.18.0.2: seq=1 ttl=64 time=0.054 ms --- alpine1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.026/0.040/0.054 ms从
alpine1，您根本无法连接到alpine3，因为它不在alpine-net网络上。# ping -c 2 alpine3 ping: bad address 'alpine3'不仅如此，您也无法通过IP地址从
alpine1连接到alpine3。回顾一下docker network inspect输出中bridge网络的信息，找到alpine3的IP地址：172.17.0.2尝试ping它。# ping -c 2 172.17.0.2 PING 172.17.0.2 (172.17.0.2): 56 data bytes --- 172.17.0.2 ping statistics --- 2 packets transmitted, 0 packets received, 100% packet loss使用分离序列从
alpine1分离，CTRL+pCTRL+q（按住CTRL并依次输入p和q）。请记住，
alpine4同时连接到默认的bridge网络和alpine-net。它应该能够访问所有其他容器。 但是，您需要通过 IP 地址来访问alpine3。连接到它并运行测试。$ docker container attach alpine4 # ping -c 2 alpine1 PING alpine1 (172.18.0.2): 56 data bytes 64 bytes from 172.18.0.2: seq=0 ttl=64 time=0.074 ms 64 bytes from 172.18.0.2: seq=1 ttl=64 time=0.082 ms --- alpine1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.074/0.078/0.082 ms # ping -c 2 alpine2 PING alpine2 (172.18.0.3): 56 data bytes 64 bytes from 172.18.0.3: seq=0 ttl=64 time=0.075 ms 64 bytes from 172.18.0.3: seq=1 ttl=64 time=0.080 ms --- alpine2 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.075/0.077/0.080 ms # ping -c 2 alpine3 ping: bad address 'alpine3' # ping -c 2 172.17.0.2 PING 172.17.0.2 (172.17.0.2): 56 data bytes 64 bytes from 172.17.0.2: seq=0 ttl=64 time=0.089 ms 64 bytes from 172.17.0.2: seq=1 ttl=64 time=0.075 ms --- 172.17.0.2 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.075/0.082/0.089 ms # ping -c 2 alpine4 PING alpine4 (172.18.0.4): 56 data bytes 64 bytes from 172.18.0.4: seq=0 ttl=64 time=0.033 ms 64 bytes from 172.18.0.4: seq=1 ttl=64 time=0.064 ms --- alpine4 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.033/0.048/0.064 ms作为最后的测试，请确保您的容器都能通过 ping
google.com连接到互联网。您已经连接到alpine4，所以先从那里开始尝试。接下来，断开与alpine4的连接并连接到alpine3（仅连接到bridge网络），然后再次尝试。最后，连接到alpine1（仅连接到alpine-net网络），然后再次尝试。# ping -c 2 google.com PING google.com (172.217.3.174): 56 data bytes 64 bytes from 172.217.3.174: seq=0 ttl=41 time=9.778 ms 64 bytes from 172.217.3.174: seq=1 ttl=41 time=9.634 ms --- google.com ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 9.634/9.706/9.778 ms CTRL+p CTRL+q $ docker container attach alpine3 # ping -c 2 google.com PING google.com (172.217.3.174): 56 data bytes 64 bytes from 172.217.3.174: seq=0 ttl=41 time=9.706 ms 64 bytes from 172.217.3.174: seq=1 ttl=41 time=9.851 ms --- google.com ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 9.706/9.778/9.851 ms CTRL+p CTRL+q $ docker container attach alpine1 # ping -c 2 google.com PING google.com (172.217.3.174): 56 data bytes 64 bytes from 172.217.3.174: seq=0 ttl=41 time=9.606 ms 64 bytes from 172.217.3.174: seq=1 ttl=41 time=9.603 ms --- google.com ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 9.603/9.604/9.606 ms CTRL+p CTRL+q停止并移除所有容器以及
alpine-net网络。$ docker container stop alpine1 alpine2 alpine3 alpine4 $ docker container rm alpine1 alpine2 alpine3 alpine4 $ docker network rm alpine-net