```bash
RUN mv /etc/apt/sources.list /etc/apt/sources.list.bak
RUN echo "deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse" >>/etc/apt/sources.list
RUN echo "deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse" >>/etc/apt/sources.list
RUN echo "deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse" >>/etc/apt/sources.list

直接在dockerfile修改即可