I have the same problem with proxmox 3.2.
I created a container from debian-7.0-standard_7.0-2_i386.tar.gz which works until I try an update of openssh in this container (from version 6.0p1-4 to 6.0p1-4+deb7u1), then ssh does not start (PRNG is not seeded) and there are messages like...