是在docker虚拟机中运行的命令
Err:1 http://mirrors.ustc.edu.cn/ubuntu xenial InRelease
Connection failed [IP: 202.38.95.110 80]
Get:2 http://mirrors.ustc.edu.cn/ubuntu xenial-security InRelease [109 kB]
Err:2 http://mirrors.ustc.edu.cn/ubuntu xenial-security InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY xxx NO_PUBKEY zzz
Get:3 http://mirrors.ustc.edu.cn/ubuntu xenial-updates InRelease [109 kB]
Err:3 http://mirrors.ustc.edu.cn/ubuntu xenial-updates InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY xxx NO_PUBKEY zzz
Get:4 http://mirrors.ustc.edu.cn/ubuntu xenial-proposed InRelease [260 kB]
Err:4 http://mirrors.ustc.edu.cn/ubuntu xenial-proposed InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY xxx NO_PUBKEY zzz
Get:5 http://mirrors.ustc.edu.cn/ubuntu xenial-backports InRelease [107 kB]