我使用以下Dockerfile构建一个Rails应用容器：

$ cat Dockerfile
FROM ruby:2.2

MAINTAINER Luca G. Soave <luca.soave@gmail.com>

RUN apt-get update && apt-get install -y nodejs --no-install-recommends && rm -rf /var/lib/apt/lists/*
RUN apt-get update && apt-get install -y mysql-client postgresql-client sqlite3 --no-install-recommends && rm -rf /var/lib/apt/lists/*

RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

COPY . /usr/src/app/
RUN bundle install

EXPOSE 3000
CMD ["rails", "server"]

构建成功：

$ docker build -t querier .
Sending build context to Docker daemon 46.75 MB
Sending build context to Docker daemon 
...
Step 10 : CMD rails server
 ---> Running in 8eb62f8a579a
 ---> 65eee929d518
Removing intermediate container 8eb62f8a579a
Successfully built 65eee929d518

容器正在运行：

$ docker logs -f 89ff3bb8c584
=> Booting WEBrick
=> Rails 4.2.0 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
[2015-01-06 19:56:56] INFO  WEBrick 1.3.1
[2015-01-06 19:56:56] INFO  ruby 2.2.0 (2014-12-25) [x86_64-linux]
[2015-01-06 19:56:56] INFO  WEBrick::HTTPServer#start: pid=1 port=3000

并且正在导出3000 / tcp端口：

$ docker ps -al
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                    NAMES
89ff3bb8c584        querier:latest      "rails server"      16 minutes ago      Up 16 minutes       0.0.0.0:3000->3000/tcp   gloomy_babbage

但无法从“内部”或“外部” Docker访问服务器：

$ curl 0.0.0.0:3000
curl: (56) Recv failure: Connection reset by peer
$ curl 172.17.0.24:3000
curl: (7) Failed to connect to 172.17.0.24 port 3000: Connection refused

但一切似乎还可以：

$ docker inspect --format '{{ .NetworkSettings.IPAddress }}' 89ff3bb8c584
172.17.0.24
$ netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         10.36.32.1      0.0.0.0         UG        0 0          0 wlan0
10.0.3.0        *               255.255.255.0   U         0 0          0 lxcbr0
10.36.32.0      *               255.255.248.0   U         0 0          0 wlan0
172.17.0.0      *               255.255.0.0     U         0 0          0 docker0

$ ping 0.0.0.0
PING 0.0.0.0 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.069 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.061 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.069 ms
^C
--- 0.0.0.0 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.061/0.066/0.069/0.007 ms

$ ping 172.17.0.24
PING 172.17.0.24 (172.17.0.24) 56(84) bytes of data.
64 bytes from 172.17.0.24: icmp_seq=1 ttl=64 time=0.085 ms
64 bytes from 172.17.0.24: icmp_seq=2 ttl=64 time=0.107 ms
64 bytes from 172.17.0.24: icmp_seq=3 ttl=64 time=0.076 ms
^C

我也在浏览器中尝试过，但是什么也没有。主机系统是：

$ docker -v
Docker version 1.4.1, build 5bc2ff8
$ uname -a 
Linux basenode 3.11.0-18-generic #32-Ubuntu SMP Tue Feb 18 21:11:14 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

任何的想法？