独立容器网络
本系列教程介绍独立 Docker 容器的网络连接。有关使用 Swarm 服务进行网络连接的信息，请参见 使用 Swarm 服务进行网络连接。如果您需要了解有关 Docker 网络的更多一般信息，请参见 概述。
本主题包含两个不同的教程。您可以在 Linux、Windows 或 Mac 上运行每个教程，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 演示如何使用 Docker 自动为您设置的默认
bridge网络。此网络不是生产系统的最佳选择。使用用户定义的桥接网络 演示如何创建和使用您自己的自定义桥接网络，以连接在同一 Docker 主机上运行的容器。这推荐用于在生产环境中运行的独立容器。
尽管 overlay 网络 通常用于 Swarm 服务，但您也可以将 overlay 网络用于独立容器。这在 使用 overlay 网络的教程 中有所介绍。
使用默认桥接网络
在此示例中，您在同一 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。
打开一个终端窗口。在执行任何其他操作之前，列出当前网络。如果您从未在此 Docker 守护程序上添加网络或初始化 Swarm，则应该看到以下内容。您可能会看到不同的网络，但您至少应该看到这些（网络 ID 将有所不同）
$ docker network ls NETWORK ID NAME DRIVER SCOPE 17e324f45964 bridge bridge local 6ed54d316334 host host local 7092879f2cc8 none null local列出了默认的
bridge网络，以及host和none。后两者不是完整的网络，而是用于启动直接连接到 Docker 守护程序主机网络堆栈的容器，或启动没有网络设备的容器。本教程将两个容器连接到bridge网络。启动两个运行
ash的alpine容器，它是 Alpine 的默认 shell，而不是bash。-dit标志表示以分离模式（在后台）、交互模式（能够键入）和带有 TTY（以便您可以看到输入和输出）启动容器。由于您以分离模式启动它，因此您不会立即连接到容器。相反，将打印容器 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网络以查看哪些容器已连接到它。$ 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": {} } ]在顶部附近，列出了有关
bridge网络的信息，包括 Docker 主机和bridge网络之间的网关的 IP 地址（172.17.0.1）。在Containers密钥下，列出了每个连接的容器，以及有关其 IP 地址的信息（alpine1为172.17.0.2，alpine2为172.17.0.3）。容器在后台运行。使用
docker attach命令连接到alpine1。$ docker attach alpine1 / #提示符更改为
#，表示您是容器中的root用户。使用ip addr show命令显示alpine1的网络接口，就像它们在容器内的外观一样。# 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第一个接口是环回设备。暂时忽略它。请注意，第二个接口的 IP 地址为
172.17.0.2，与上一步中显示的alpine1的地址相同。在
alpine1中，通过 pinggoogle.com确保您可以连接到互联网。-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，使用其 IP 地址
172.17.0.3ping 它。# 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这成功了。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'使用分离序列
CTRL+pCTRL+q（按住CTRL并键入p然后键入q）从alpine1分离而不停止它。如果愿意，可以连接到alpine2并在此重复步骤 4、5 和 6，将alpine1替换为alpine2。停止并删除两个容器。
$ docker container stop alpine1 alpine2 $ docker container rm alpine1 alpine2
请记住，不推荐将默认的 bridge 网络用于生产环境。要了解用户定义的桥接网络，请继续阅读 下一个教程。
使用用户定义的桥接网络
在此示例中，我们再次启动两个 alpine 容器，但将它们连接到我们已创建的名为 alpine-net 的用户定义网络。这些容器根本没有连接到默认的 bridge 网络。然后，我们启动第三个连接到 bridge 网络但不连接到 alpine-net 的 alpine 容器，以及第四个连接到两个网络的 alpine 容器。
创建
alpine-net网络。您不需要--driver bridge标志，因为它是默认值，但此示例显示了如何指定它。$ 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。这将向您显示其 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，此网络的网关为
172.18.0.1，而不是默认桥接网络的网关172.17.0.1。确切的 IP 地址在您的系统上可能有所不同。创建四个容器。请注意
--network标志。您只能在docker run命令期间连接到一个网络，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连接到alpine-net网络。在像
alpine-net这样的用户定义网络上，容器不仅可以通过 IP 地址进行通信，还可以将容器名称解析为 IP 地址。此功能称为自动服务发现。让我们连接到alpine1并测试一下。alpine1应该能够将alpine2和alpine4（以及alpine1本身）解析为 IP 地址。注意
自动服务发现只能解析自定义容器名称，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由于 `alpine3` 不在 `alpine-net` 网络中，因此您无法从 `alpine1` 连接到 `alpine3`。
# ping -c 2 alpine3 ping: bad address 'alpine3'不仅如此，您也不能通过 IP 地址从 `alpine1` 连接到 `alpine3`。查看 `docker network inspect` 的 `bridge` 网络输出，找到 `alpine3` 的 IP 地址：`172.17.0.2`，尝试 ping 一下。
# 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 `CTRL` + `p` `CTRL` + `q` (按住 `CTRL` 并依次输入 `p` 和 `q`) 从 `alpine1` 分离。
请记住，`alpine4` 连接到默认的 `bridge` 网络和 `alpine-net` 网络。它应该能够访问所有其他容器。但是，您需要使用 IP 地址访问 `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，确保您的容器都可以通过 ping `google.com` 来连接互联网。您已经连接到 `alpine4`，所以先从那里尝试。接下来，从 `alpine4` 分离并连接到 `alpine3`（仅连接到 `bridge` 网络）并再次尝试。最后，连接到 `alpine1`（仅连接到 `alpine-net` 网络）并再次尝试。
# 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停止并删除所有容器和 `alpine-net` 网络。
$ docker container stop alpine1 alpine2 alpine3 alpine4 $ docker container rm alpine1 alpine2 alpine3 alpine4 $ docker network rm alpine-net