报错 ：   

E: Failed to fetch https://developer.download.nvidia.cn/compute/cuda/repos/ubuntu2004/x86_64/by-hash/SHA256/60afcf24526893b1713a7ce2d773cabe942d80dd637ba44327e34e890118a730  404  Not Found [IP: 180.97.232.92 443]
E: Some index files failed to download. They have been ignored, or old ones used instead.

Err:11 https://developer.download.nvidia.cn/compute/cuda/repos/ubuntu2004/x86_64  Packages
  404  Not Found [IP: 180.97.232.92 443]

在如下网页中找到：

https://github.com/NVIDIA/nvidia-docker/issues/619

解决方法，执行

 rm /etc/apt/sources.list.d/cuda.list

FROM nvidia/cuda:8.0-cudnn6-devel-ubuntu16.04

RUN rm /etc/apt/sources.list.d/cuda.list

执行命令后 显示：

root@077dbe967071:/home/l1# apt-key adv --fetch-keys http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/7fa2af80.pub
Executing: /tmp/apt-key-gpghome.v9PegdjuZh/gpg.1.sh --fetch-keys http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/7fa2af80.pub
gpg: requesting key from 'http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/7fa2af80.pub'
gpg: key F60F4B3D7FA2AF80: "cudatools <cudatools@nvidia.com>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1

执行后  apt-get update   可以执行：

root@077dbe967071:/home/l1# apt-get update
Hit:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu bionic InRelease
Hit:2 https://mirrors.tuna.tsinghua.edu.cn/ubuntu bionic-updates InRelease
Hit:3 https://mirrors.tuna.tsinghua.edu.cn/ubuntu bionic-backports InRelease
Hit:4 https://mirrors.tuna.tsinghua.edu.cn/ubuntu bionic-security InRelease
Hit:5 https://nvidia.github.io/libnvidia-container/ubuntu16.04/amd64  InRelease
Hit:6 https://nvidia.github.io/nvidia-container-runtime/ubuntu16.04/amd64  InRelease
Hit:7 https://nvidia.github.io/nvidia-docker/ubuntu16.04/amd64  InRelease
Reading package lists... Done
root@077dbe967071:/home/l1#