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1. Add the following key to hiera:

   1. placement::policy::purge_config: true

2. Install the first node; either by resintaling it with the xena modules/tags, or follow this list:
   1. Run puppet with xena modules/tags

   2. Run systemctl stop puppet apache2

   3. Run apt-get purge placement-api placement-common python3-placement && apt-get autoremove && apt-get dist-upgrade
   4. Run puppet again
3. Run placement-manage db sync; placement-manage db online_data_migrations on the new node.
4. upgrade the rest of the nodes, skipping step 23.

Nova

To upgrade nova without any downtime, follow this procedure

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