How to set root password in overcloud nodes?

Issue

In default, root user in overcloud nodes does not have password configured, thus we can not login to the node via console.
How can we set root password to do some troubleshooting via console?
In Red Hat OpenStack Platform 17, NodeRootPassword described in Enabling root user login on Red Hat OpenStack Platform nodes and How to set root password in overcloud nodes? doesn't work.

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