解决：Connecting to raw.githubusercontent.com failed 以及 Connection refused

用Dockerfile制作镜像 设置的 ubuntu环境下自动下载docker-compose和maven，刚开始连接的是 raw.githubusercontent.com 这个地址，一直报错。

找资料有的说是需要加参数 “wget --no-check-certificate”，有的说是因为dns污染需要添加地址到system32里面的hosts里面去，我自己试了都不行，只能考虑是墙的问题了。那没办法，换地址吧

docker-compose 下载地址 和 maven 安装包地址都更改成了 国内的地址如下（注意：该maven压缩包仓库版本不全，有的不存在，若更改版本请首先链接验证）：

FROM gitlab/gitlab-runner:v11.1.0
MAINTAINER Gbx <[email protected]>

# 修改软件源
RUN echo 'deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse' > /etc/apt/sources.list && \
    echo 'deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse' >> /etc/apt/sources.list && \
    echo 'deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse' >> /etc/apt/sources.list && \
    echo 'deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse' >> /etc/apt/sources.list && \
    apt-get update -y && \
    apt-get clean

# 安装 Docker
RUN apt-get -y install apt-transport-https ca-certificates curl software-properties-common && \
    curl -fsSL http://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg | apt-key add - && \
    add-apt-repository "deb [arch=amd64] http://mirrors.aliyun.com/docker-ce/linux/ubuntu $(lsb_release -cs) stable" && \
    apt-get update -y && \
    apt-get install -y docker-ce
COPY daemon.json /etc/docker/daemon.json

# 安装 Docker Compose
WORKDIR /usr/local/bin
RUN curl -L https://get.daocloud.io/docker/compose/releases/download/1.21.2/docker-compose-`uname -s`-`uname -m` > ./docker-compose
RUN chmod +x docker-compose

# 安装 Java
RUN mkdir -p /usr/local/java
WORKDIR /usr/local/java
COPY jdk-8u152-linux-x64.tar.gz /usr/local/java
RUN tar -zxvf jdk-8u152-linux-x64.tar.gz && \
    rm -fr jdk-8u152-linux-x64.tar.gz

# 安装 Maven
RUN mkdir -p /usr/local/maven
WORKDIR /usr/local/maven
RUN wget http://mirrors.hust.edu.cn/apache/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.tar.gz
# COPY apache-maven-3.6.3-bin.tar.gz /usr/local/maven
RUN tar -zxvf apache-maven-3.6.3-bin.tar.gz && \
    rm -fr apache-maven-3.6.3-bin.tar.gz
# COPY settings.xml /usr/local/maven/apache-maven-3.6.3/conf/settings.xml

# 配置环境变量
ENV JAVA_HOME /usr/local/java/jdk1.8.0_152
ENV MAVEN_HOME /usr/local/maven/apache-maven-3.6.3
ENV PATH $PATH:$JAVA_HOME/bin:$MAVEN_HOME/bin

WORKDIR /

再次构建就能成功运行了。

附：同目录下daemon.json:

{
  "registry-mirrors": [
    "https://registry.docker-cn.com"
  ],
  "insecure-registries": [
    "192.168.75.131:5000"
  ]
}