Linux Ubuntu服务器证书问题 server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.

Linux ubuntu 16.04

使用apt-get update和apt-get install时报错： server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt 

Err:39 https://nvidia.github.io/libnvidia-container/ubuntu16.04/amd64  Packages
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
Err:40 https://nvidia.github.io/nvidia-container-runtime/ubuntu16.04/amd64  Packages
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
Ign:68 http://www.getdeb.net/ubuntu xenial-getdeb/apps amd64 DEP-11 Metadata
Err:41 https://nvidia.github.io/nvidia-docker/ubuntu16.04/amd64  Packages
  server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

原因：可能是没有CA证书。

解决：找同事或者其他途径获取到专用的CA证书（rootca.crt文件），然后更新证书

# 1，将获取到的证书文件放置到  /usr/local/share/ca-certificates 目录下
$ sudo cp ~/Downloads/rootca.crt /usr/local/share/ca-certificates/

# 更新证书，注意命令是 update-ca-certificates
$ sudo update-ca-certificates