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1. Select which glance-server to upgrade first.
   1. In the node-specific hiera for this host you should set: 
      1. glance::api::enabled: false
      2. apache::service_ensure: 'stopped'
2. Run puppet with the zed modules/tags, run apt-get dist-upgrade, and run puppet again
3. Remove the glance::api::enable: false and apache::service_ensure: 'stopped' from the node-specific hiera, and run puppet again. This would re-start the glance api-server on this host.
   1. Test that this api-server works.
4. Upgrade the rest of the glance hosts (ie; step 2 for each of the remaining glance hosts)

Cinder

To upgrade cinder without any downtime, follow this procedure

1. Add the following three lines to the node-file of the first node you would like to upgrade:
   

   1. apache::service_ensure: 'stopped'

   2. cinder::scheduler::enabled: false

   3. cinder::volume::enabled: false

2. Run puppet with the zed modules/tags, run apt-get dist-upgrade, and run puppet again
3. Run cinder-manage db sync && cinder-manage db online_data_migrations
4. Remove the lines added at step 1, re-run puppet, and test that the upgraded cinder version works.
5. Perfom step 2 for the rest of the cinder nodes