Symptoms
While creating OS template cache, the following error appears:
TypeError: an integer is required
error: python callback <bound method RPMTransaction.callback of <yum.rpmtrans.RPMTransaction instance at 0x220e5a8>> failed, aborting!
Error: /usr/share/vzyum/bin/yum failed, exitcode=1
Cause
/vz partition is mounted as NFS version 4, while ploop format can be used only with NFSv3 file system. OS Template cache creation procedure includes a temporary ploop container, which cannot be created due to NFSv4 restriction.
Resolution
Use NFSv3 for /vz instead.