码头工人:错误:不可满足的约束

Question

我试图从https://docs.docker.com/compose/gettingstarted/建立码头形象的例子。我得到了这个错误

Building web
Step 1/9 : FROM python:3.7-alpine
 ---> e854017db514
Step 2/9 : WORKDIR /code
 ---> Using cache
 ---> e15b6e62d8af
Step 3/9 : ENV FLASK_APP app.py
 ---> Using cache
 ---> 759c4bc8b254
Step 4/9 : ENV FLASK_RUN_HOST 0.0.0.0
 ---> Using cache
 ---> 6d40793f3089
Step 5/9 : RUN apk add --no-cache gcc musl-dev linux-headers
 ---> Running in 5e40bd670f1b
fetch http://dl-cdn.alpinelinux.org/alpine/v3.11/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.11/community/x86_64/APKINDEX.tar.gz
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.11/main/x86_64/APKINDEX.tar.gz: Permission denied
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.11/community/x86_64/APKINDEX.tar.gz: Permission denied
ERROR: unsatisfiable constraints:
  gcc (missing):
    required by: world[gcc]
  linux-headers (missing):
    required by: world[linux-headers]
  musl-dev (missing):
    required by: world[musl-dev]
ERROR: Service 'web' failed to build: The command '/bin/sh -c apk add --no-cache gcc musl-dev linux-headers' returned a non-zero code: 3

这是我的文件

FROM python:3.7-alpine
WORKDIR /code
ENV FLASK_APP app.py
ENV FLASK_RUN_HOST 0.0.0.0
RUN apk add --no-cache gcc musl-dev linux-headers
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
COPY . .
CMD ["flask", "run"]

你能帮我解决这个错误吗？谢谢大家！

Answer 1

要安装的包是否移动到另一个注册表？

有时，正在安装的包从不同的注册表分支中移动。默认的Docker阿尔卑斯映像只设置了某些注册表。添加其他注册中心可以扩展您的安装选项(YMMV)；我不能谈论与不同注册表分支相关联的稳定性、安全性和风险。这条线帮了我。

失败的尝试和错误消息：

❯ docker run -it alpine sh                                                                                                                                                                 
/ # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz
v3.12.0-175-g8b3334c57c [http://dl-cdn.alpinelinux.org/alpine/v3.12/main]
v3.12.0-178-gb27c83e867 [http://dl-cdn.alpinelinux.org/alpine/v3.12/community]
OK: 12749 distinct packages available
/ # apk add cowsay
ERROR: unsatisfiable constraints:
  cowsay (missing):
    required by: world[cowsay]
/ # 

1. 我们输出的第一条线索

ERROR: unsatisfiable constraints:
       cowsay (missing):
       required by: world[cowsay]

1. 输出的第二条线索

在日志的前面

fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz

溶化

1. 在DuckDuckGo上搜索package <package name>

• 告诉我网址：https://pkgs.org/download/cowsay

我使用的是哪种类型的内存？

• 答案在线索# 2. x86_64中找到

在包的页面上选择适当的链接。所以就我而言：

• 高寒测试x86_64 > cowsay-3.04-r0.apk

阅读该页面上的信息，我看到在下载下，该包的二进制位于

• http://dl-cdn.alpinelinux.org/alpine/edge/testing/x86_64/cowsay-3.04-r0.apk

与线索2相比，我发现高寒容器并没有用我想要安装的二进制文件引用注册表。

成功& TL;DR；

通过向停靠高寒容器添加附加注册表，将以前未找到的包添加到阿尔卑斯。

我将添加注册表，以找到要安装的包(步骤3)。在下面的代码块中，可以看到第三个注册表与第3部分中的URL的初始部分相匹配。我不想替换现有的注册中心(线索2)，所以我再次设置了这些注册中心。我不知道这是否有必要，但我还是做了。

$ docker run -it alpine sh
/# apk update && apk add cowsay \
        --update-cache \
        --repository https://alpine.global.ssl.fastly.net/alpine/edge/community \
        --repository https://alpine.global.ssl.fastly.net/alpine/edge/main \
        --repository https://dl-3.alpinelinux.org/alpine/edge/testing
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.12/community/x86_64/APKINDEX.tar.gz
v3.12.0-175-g8b3334c57c [http://dl-cdn.alpinelinux.org/alpine/v3.12/main]
v3.12.0-178-gb27c83e867 [http://dl-cdn.alpinelinux.org/alpine/v3.12/community]
OK: 12749 distinct packages available
fetch https://dl-3.alpinelinux.org/alpine/edge/testing/x86_64/APKINDEX.tar.gz
fetch https://alpine.global.ssl.fastly.net/alpine/edge/main/x86_64/APKINDEX.tar.gz
fetch https://alpine.global.ssl.fastly.net/alpine/edge/community/x86_64/APKINDEX.tar.gz
(1/3) Installing libbz2 (1.0.8-r1)
(2/3) Installing perl (5.30.3-r2)
(3/3) Installing cowsay (3.04-r0)
Executing busybox-1.31.1-r16.trigger
OK: 43 MiB in 17 packages
/ #

Dockerfile示例

FROM alpine
RUN apk update && apk add cowsay \
        --update-cache \
        --repository https://alpine.global.ssl.fastly.net/alpine/edge/community \
        --repository https://alpine.global.ssl.fastly.net/alpine/edge/main \
        --repository https://dl-3.alpinelinux.org/alpine/edge/testing
CMD ["cowsay", "hi stackoverflow"]

生成此文件后：

 ❯ docker run cowsay                                                                                                                                                                        [13:13:45]
 __________________ 
< hi stackoverflow >
 ------------------ 
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||