We know that 3.6 is capable of creating bad files in /var/lib/dockershim/sandbox. After we drain a node in preparation to upgrade we should delete all of those files (on a well behaved system there would not be any such files after a drain).
A future 3.7.z version of openshift will correctly clean those files up themselves. However this is needed to clean up after 3.6 when running 3.7.4 (the GA version).
Verified on openshift-ansible-3.7.8-1.git.0.9a3db79.el7.noarch.
Monitor /var/lib/dockershim/sandbox/ directory during upgrade v3.6 to v3.7, the files in the directory will be cleaned up after drain node. And new files will be created when new pod created.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.