[Docker] IPv6+nginx+php 讓docker中的容器支援ipv6，讀取到外部ipv6 @新精讚

1這篇我研究6個小時，解決了大大小小的問題，也稍微搞清楚了docker的網路架構。

這次的任務不單單是要讓docker容器(container)中能直接用ip6來連線外，還要讓容器中能取得來源的ip6。

系統

# cat /etc/redhat-release
Rocky Linux release 9.0 (Blue Onyx)

# docker version
Client: Docker Engine - Community
Version: 20.10.21

Server: Docker Engine - Community
Engine:
Version: 20.10.21

# docker compose version
Docker Compose version v2.12.2

架構

外部網路 ==>

載體OS (2001:288:1234:2::2/64) ==>

docker0 (fd00:ffff::1/80) ==>

net6 (fd00:ffff:1::1/80) ==>

nginx (fd00:ffff:1::3/80 auto)
php(fd00:ffff:1::5/80 auto)

外部網路連到載體OS的ip6是Global Address；裡面的ip6是Unique Local Address (ULA)。

docker設定

啟動ip6路由

新增 /etc/docker/daemon.json ^[1][2]

{
"ipv6": true,
"fixed-cidr-v6": "fd00:ffff::/80",
"ip6tables": true,
"experimental": true
}

重啟docker後會看到 docker0 這個介面出現^[2][3]。

後面二行如果沒有加的話，還是會通，只是會變成snat mode，加了這兩行變routing mode。如果出現錯誤，請參考下面錯誤排除^[5]。

docker compose

新增一個網路 net6，並將nginx,php 加入此網路。

version: '3.8'

services:
nginx:
      image: nginx:latest
      ports:
        - "80:80"
        - "443:443"
      networks:
        - net6

php:
    image: php:8.1-fpm-mysqli
    ports:
      - 9000
    networks:
        - net6

networks:
net6:
    name: net6
    enable_ipv6: true <== 一定要加
    driver: bridge    <== 可加可不加
    ipam:
      config:
        - subnet: fd00:ffff:1::/80
          gateway: fd00:ffff:1::1
        - subnet: "172.16.163.0/24"

上面可以看到 net6 中的ip6有指定一個網路和gateway，ip4的subnet部分非必要。

enable_ipv6: true 這個看文件說 3.0後就會出錯，所以我一開始沒加，後來發現不加的話，容器中的ip6就不生效了。
容器中的ip6一直無法生效但是又找不到原因，後來意外發現networks還是使用 2.X的版本(請看下面測試)，明明我指定3.8的版本…

重啟 docker compose 生效

測試

1. 查看網路介面，應該有 docker0

# ip addr
...
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether b6:c8:22:05:84:1c brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global noprefixroute docker0
       valid_lft forever preferred_lft forever
    inet6 fd00:ffff::1/80 scope global tentative
       valid_lft forever preferred_lft forever
    inet6 fe80::1/64 scope link tentative
       valid_lft forever preferred_lft forever

2. 查看 docker net6

# docker inspect net6
[
    {
        "Name": "net6",
        "Id": "7d229137b375fe741cf61800583930770a1a27ac48862e87d03e12ae87e1f080",
        "Created": "2023-01-04T11:07:21.810957973+08:00",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": true,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.16.163.0/24"
                },
                {
                    "Subnet": "fd00:ffff:1::/80",
                    "Gateway": "fd00:ffff:1::1"
                }
            ]
        },

... 略 ...

        "Containers": {
            "5d50ad4e738ad6674a1943f34595fd0b40f7c4720e41c10e56e4662c93889292": {
                "Name": "php",
                "EndpointID": "253124353ab62132ae68246d01872eca68ecf9eb2d4c7b2868358aa4aa764355",
                "MacAddress": "02:42:ac:10:a3:05",
                "IPv4Address": "172.16.163.5/24",
                "IPv6Address": "fd00:ffff:1::5/80"
            },
            "773a7dde22c25759fda04d416dd0ad7630cefc34420792c298f9f72813e8eef4": {
                "Name": "nginx",
                "EndpointID": "329e487d578db0e32e32fff219f8ee411e44d0b02453271922ef8dd9345dff8d",
                "MacAddress": "02:42:ac:10:a3:03",
                "IPv4Address": "172.16.163.3/24",
                "IPv6Address": "fd00:ffff:1::3/80"
            },

IPv6Address 的位址是自動產生的，每次都會不一樣。

ping6 看看該位址是否能順利取得。

3. 查看路由

大致上這樣，綠色的部分ok

# ip -6 route
::1 dev lo proto kernel metric 256 pref medium
2001:288:1234:2::/64 dev ens192 proto kernel metric 100 pref medium
fd00:ffff::/80 dev docker0 proto kernel metric 256 linkdown pref medium
fd00:ffff::/80 dev docker0 metric 1024 linkdown pref medium
fd00:ffff:1::/80 dev br-7d229137b375 proto kernel metric 256 pref medium
fe80::/64 dev docker0 proto kernel metric 256 linkdown pref medium
fe80::/64 dev br-7d229137b375 proto kernel metric 256 pref medium
fe80::/64 dev br-5c0b5382ef95 proto kernel metric 256 pref medium
fe80::/64 dev vethca3313c proto kernel metric 256 pref medium
fe80::/64 dev veth0917957 proto kernel metric 256 pref medium
fe80::/64 dev ens192 proto kernel metric 1024 pref medium
default via 2001:288:1234:2::ff dev ens192 proto static metric 100 pref medium

4. 網頁測試

index.php

<?php
phpinfo();

查看 REMOTE_ADDR 是不是外部的ip6 ?