Proxmox apt-get update 更新报错：

Err:4 https://enterprise.proxmox.com/debian/pve stretch/pve-enterprise amd64 Packages
  401  Unauthorized
Ign:5 https://enterprise.proxmox.com/debian/pve stretch/pve-enterprise all Packages
Ign:6 https://enterprise.proxmox.com/debian/pve stretch/pve-enterprise Translation-en
Ign:8 http://ftp.debian.org/debian stretch InRelease
Ign:7 https://enterprise.proxmox.com/debian/pve stretch/pve-enterprise Translation-en_US
Hit:9 http://ftp.debian.org/debian stretch Release
Reading package lists... Done
W: The repository 'https://enterprise.proxmox.com/debian/pve stretch Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch https://enterprise.proxmox.com/debian/pve/dists/stretch/pve-enterprise/binary-amd64/Packages  401  Unauthorized
E: Some index files failed to download. They have been ignored, or old ones used instead.

这个是因为没有购买401无权使用这个更新源,可以修改/etc/apt/sources.list.d/pve-enterprise.list注释掉解决
#deb https://enterprise.proxmox.com/debian/pve stretch pve-enterprise

Proxmox VE 无订阅更新源,不建议生产环境使用.
修改/etc/apt/sources.list
deb http://ftp.debian.org/debian stretch main contrib
# PVE pve-no-subscription repository provided by proxmox.com,
# NOT recommended for production use
deb http://download.proxmox.com/debian/pve stretch pve-no-subscription
# security updates
deb http://security.debian.org stretch/updates main contrib