为什么Docker中httpd容器会立即退出而没有任何错误

Question

我是 Docker 新手。我的 Dockerfile（从教程中获得）是：

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FROM ubuntu\n\nENV DEBIAN_FRONTEND noninteractive\n\nRUN apt-get update \\\n&& apt-get install -y --no-install-recommends apache2 \\\n                        libapache2-mod-jk\nVOLUME ["/var/log/apache2"]\nRUN echo \'ServerName localhost\' >> /etc/apache2/apache2.conf\nEXPOSE 80 443\n\nENTRYPOINT ["apache2ctl", "-D", "FOREGROUND"]\n

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我给了docker build -t mg:httpd apache\\。没有错误。

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\xce\xbb docker images\nREPOSITORY          TAG                 IMAGE ID            CREATED                SIZE\nmg                  httpd               262d7a4f85fc        About an hour ago      248MB\n

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docker run -it mg:httpd

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没有错误，但光标立即返回到命令提示符。继续Unable to connect服用http://localhost/浏览器。

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\xce\xbb docker ps -a\nCONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                         PORTS                \n600231bbd461        mg:httpd            "apache2ctl -D FOR..."   2 minutes ago       Exited (0) 2 minutes ago             \n

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docker 日志为空

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\xce\xbb docker events\n2017-09-08T15:26:10.726720800+05:30 container create 5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157 (image=mg:httpd, name=zealous_ritchie)\n2017-09-08T15:26:10.740310700+05:30 container attach 5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157 (image=mg:httpd, name=zealous_ritchie)\n2017-09-08T15:26:11.035777100+05:30 network connect 2b8829b336575a2aa2210f55105d793e8f1b196d51845d38d3dc8ff322af6143 (container=5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157, name=bridge, type=bridge)\n2017-09-08T15:26:11.090873500+05:30 volume mount e8421cbd867fca04f0dd3ee6da815c59cad5fc32c5a427710d144213b43caa26 (container=5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157, destination=/var/log/apache2, driver=local, propagation=, read/write=true)\n2017-09-08T15:26:11.548736900+05:30 container start 5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157 (image=mg:httpd, name=zealous_ritchie)\n2017-09-08T15:26:11.573272300+05:30 container resize 5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157 (height=41, image=mg:httpd, name=zealous_ritchie, width=168)\n2017-09-08T15:26:12.733164900+05:30 container die 5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157 (exitCode=0, image=mg:httpd, name=zealous_ritchie)\n2017-09-08T15:26:13.227455500+05:30 network disconnect 2b8829b336575a2aa2210f55105d793e8f1b196d51845d38d3dc8ff322af6143 (container=5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157, name=bridge, type=bridge)\n2017-09-08T15:26:13.306885700+05:30 volume unmount e8421cbd867fca04f0dd3ee6da815c59cad5fc32c5a427710d144213b43caa26 (container=5325b79abe1988312952629165551c169a8bdc3fbe6e473cf0177859db7c0157, driver=local)\n

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可能是什么原因？容器未启动时如何查看apache log\\conf文件？

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Answer 1

所以你的Web服务器没有作为前台进程启动，这就是容器立即停止的原因。

我认为你应该改变

ENTRYPOINT ["apache2ctl", "-D", "FOREGROUND"]

到

CMD ["apache2ctl", "-D", "FOREGROUND"]

因为您希望在安装容器时运行该命令。

该ENTRYPOINT指令声明了用于执行CMD.

ENTRYPOINT ["apache2ctl", "-D", "FOREGROUND"]
results in:
$  apache2ctl -D FOREGROUND <command either from the run command line or the CMD directive>

我能找到的 Ubuntu 映像的默认命令是/bin/bash. 因此，当您使用以下命令运行容器时：

docker run -it mg:httpd

执行的结果命令将是：

$  apache2ctl -D FOREGROUND /bin/bash

这显然没有多大意义。我建议仔细阅读那篇文章，它很好地解释了细节。

经过上述更改后，它将如下所示：

(default) ENTRYPOINT ["/bin/sh", "-c"]
CMD ["apache2ctl", "-D", "FOREGROUND"]
what results in:
$  /bin/sh -c "apache2ctl -D FOREGROUND"