Comment 1 for bug 1754026

The DuplicateOptError is probably caused by reusing a ConfigOpts instance with a slightly different definition of the zfssa_rest_timeout option, and I do see at least 2 places that option is defined, in zfssaiscsi.py and zfssanfs.py:

 $ git grep zfssa_rest_timeout
 cinder/tests/unit/volume/drivers/test_zfssa.py: self.configuration.zfssa_rest_timeout = 60
 cinder/tests/unit/volume/drivers/test_zfssa.py: self.configuration.zfssa_rest_timeout = '30'
 cinder/volume/drivers/zfssa/zfssaiscsi.py: cfg.IntOpt('zfssa_rest_timeout',
 cinder/volume/drivers/zfssa/zfssaiscsi.py: self.zfssa.set_host(lcfg.san_ip, timeout=lcfg.zfssa_rest_timeout)
 cinder/volume/drivers/zfssa/zfssanfs.py: cfg.IntOpt('zfssa_rest_timeout',
 cinder/volume/drivers/zfssa/zfssanfs.py: self.zfssa.set_host(host, timeout=lcfg.zfssa_rest_timeout)
 doc/source/configuration/tables/cinder-zfssa-iscsi.inc: * - ``zfssa_rest_timeout`` = ``None``
 doc/source/configuration/tables/cinder-zfssa-nfs.inc: * - ``zfssa_rest_timeout`` = ``None``