1、添加新的仓库，出现NO_PUBKEY 

    1. root@debian10-01:~# apt-get update
    2. Hit:1 http://mirrors.163.com/debian buster InRelease
    3. Hit:2 http://mirrors.163.com/debian buster-updates InRelease
    4. Hit:3 http://mirrors.163.com/debian buster-backports InRelease
    5. Get:4 http://mirrors.163.com/debian-security buster/updates InRelease [65.4 kB]
    6. Get:5 http://mirrors.163.com/debian-security buster/updates/main Sources [178 kB]
    7. Get:6 http://download.proxmox.com/debian/pve buster InRelease [3,051 B]
    8. Err:6 http://download.proxmox.com/debian/pve buster InRelease
    9.   The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7BF2812E8A6E88E0
    10. Reading package lists... Done
    11. W: GPG error: http://download.proxmox.com/debian/pve buster InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7BF2812E8A6E88E0
    12. E: The repository 'http://download.proxmox.com/debian/pve buster InRelease' is not signed.
    13. N: Updating from such a repository can't be done securely, and is therefore disabled by default.
    14. N: See apt-secure(8) manpage for repository creation and user configuration details.

    2、导入PUBKey

    1. root@debian10-01:~# sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 7BF2812E8A6E88E0
    2. Executing: /tmp/apt-key-gpghome.SiBo77scWm/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys 7BF2812E8A6E88E0
    3. gpg: key 7BF2812E8A6E88E0: public key "Proxmox Virtual Environment 6.x Release Key <proxmox-release@proxmox.com>" imported
    4. gpg: Total number processed: 1
    5. gpg:               imported: 1
    6. root@debian10-01:~# apt update
    7. Hit:1 http://mirrors.163.com/debian buster InRelease
    8. Hit:2 http://mirrors.163.com/debian buster-updates InRelease
    9. Hit:3 http://mirrors.163.com/debian buster-backports InRelease
    10. Hit:4 http://mirrors.163.com/debian-security buster/updates InRelease
    11. Get:5 http://download.proxmox.com/debian/pve buster InRelease [3,051 B]
    12. Get:6 http://download.proxmox.com/debian/pve buster/pve-no-subscription amd64 Packages [364 kB]
    13. Fetched 364 kB in 2min 32s (2,388 B/s)
    14. Reading package lists... Done
    15. Building dependency tree
    16. Reading state information... Done
    17. 11 packages can be upgraded. Run 'apt list --upgradable' to see them.