@haraoka Welcome to the Rockstor community and thanks for confirming this potential fixed in upstream bug in our now old CenOS installer.
We do have the following issue regarding updating our CentOS installer:
But we also have the following work which is now months into development:
Which in turn would give us far more options for installing Rockstor. I’m hoping to generate both a Leap 15 and a Tumblweed based install for instance. With the Leap 15 being recommended and Tumbleweed as a more experimental option. We have a lot of work to do before that stage though and the referenced post should have updates as we go.