This normally happens when you interrupt the install of Ceph:
update available package list
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
gdisk is already the newest version (1.0.6-1.1).
ceph-common is already the newest version (15.2.15-pve1).
ceph-fuse is already the newest version (15.2.15-pve1).
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
ceph-base : Depends: ceph-common (= 14.2.21-1) but 15.2.15-pve1 is to be installed
ceph-osd : PreDepends: ceph-common (= 14.2.21-1) but 15.2.15-pve1 is to be installed
E: Unable to correct problems, you have held broken packages.
apt failed during ceph installation (25600)
I have not been able to make it work without reinstalling Proxmox, it seems to completely break things if you interrupt the Ceph install.
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