There are urgent improvements in Installing and managing Red Hat OpenStack Platform with director.

The customer's feedback is around Chapter 11. Replacing Controller nodes.
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• In section 11.1.11, Stop tripleo_nova_compute.service and tripleo_nova_placement.service are failed,
  there are no longer exist.

• In section 11.3.8.i, the db file name "ovnnb_db.ctl" is wrong.　It should be "ovnsb_db.ctl".

• In section 11.8.11.ii, sudo is required when executing "podman exec".
  ~~~

Replacing controller node chapter is crucial part for the customer who needs to replace the node.
However, there are several points which will be failed or wrong command for steps.
We should fix it quickly to reduce the unnecessary support side workload.