官方操作手册
https://pve.proxmox.com/wiki/Upgrade_from_5.x_to_6.0
更新Proxmox VE 5.4到最新版本
修改debian的镜像源地址：
echo "deb https://mirrors.ustc.edu.cn/debian/ stretch main contrib non-free
deb-src https://mirrors.ustc.edu.cn/debian/ stretch main contrib non-free
deb https://mirrors.ustc.edu.cn/debian/ stretch-updates main contrib non-free
deb-src https://mirrors.ustc.edu.cn/debian/ stretch-updates main contrib non-free
deb https://mirrors.ustc.edu.cn/debian/ stretch-backports main contrib non-free
deb-src https://mirrors.ustc.edu.cn/debian/ stretch-backports main contrib non-free
deb https://mirrors.ustc.edu.cn/debian-security/ stretch/updates main contrib non-free
deb-src https://mirrors.ustc.edu.cn/debian-security/ stretch/updates main contrib non-free" > /etc/apt/sources.list
修改pve 5.x 更新源地址为 no subscription，不使用企业更新源
echo "deb http://mirrors.ustc.edu.cn/proxmox/debian/pve/ stretch pve-no-subscription" > /etc/apt/sources.list.d/pve-no-sub.list
修改 ceph镜像更新源
echo "deb http://mirrors.ustc.edu.cn/proxmox/debian/ceph-luminous stretch main" >> /etc/apt/sources.list.d/ceph.list
开始更新即可
apt update && apt dist-upgrade
2、升级Corosync到Corosync 3
关闭高可用服务，只有一台pve的可以忽略。
systemctl stop pve-ha-lrm
systemctl stop pve-ha-crm
添加Proxmox Corosync 3 Stretch存储库
echo "deb http://mirrors.ustc.edu.cn/proxmox/debian/corosync-3/ stretch main" > /etc/apt/sources.list.d/corosync3.list
运行命令更新
apt update
根据官方手册支持执行：
apt list --upgradeable
apt dist-upgrade --download-only
apt dist-upgrade
如果关闭了高可用服务的在更新完毕后需要重新启动高可用服务
systemctl start pve-ha-lrm
systemctl start pve-ha-crm
3、升级到Proxmox 6.0
执行以下更新命令确保最新：
apt update
apt dist-upgrade
执行镜像源更新命令，将Debian的镜像源更换为升级源
sed -i 's/stretch/buster/g' /etc/apt/sources.list
添加Proxmox VE 6的镜像存储库地址
echo "deb http://mirrors.ustc.edu.cn/proxmox/debian/pve buster pve-no-subscription " > /etc/apt/sources.list.d/pve-no-sub.list
修改其他镜像源的升级包地址
sed -i -e 's/stretch/buster/g' /etc/apt/sources.list.d/pve-install-repo.list
修改Ceph的升级包地址
echo "deb http://mirrors.ustc.edu.cn/proxmox/debian/ceph-luminous buster main" > /etc/apt/sources.list.d/ceph.list
开始运行更新命令
apt update
apt dist-upgrade
在更新的过程中会出现几次输入的交互，第一次提示apt相关信息，输入Q退出继续执行更新，后续直接确认回车即可。
相关参考地址转至
https://blog.51cto.com/tasnrh/2423364
