8.2 Starting the Docker Engine with User Namespace Remapping set to default can fail

Starting the Docker Engine with User Namespace Remapping set to default can fail with an error during the creation of the dockremap user. For example:

# dockerd --userns-remap default
Error during "dockremap" user creation: Couldn't create subordinate ID
ranges: Unable to add subuid range to user: "dockremap"; output: usermod:
invalid option -- 'v'
Usage: usermod [options] LOGIN

Creating a manual map file is unaffected by this issue.