OpenStack host maintenance and upgrade in interaction with application on top of it

Gerrit User 22348 b44da4ba6e Update patch set 1 ... Patch Set 1: Verified+1 Build succeeded (check pipeline). - openstack-tox-pep8 https://zuul.opendev.org/t/openstack/build/15618dd918c64e778512f0ffa2df21a4 : SUCCESS in 3m 24s - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/f94c1b2a2b0246d7962ebadb3b00320d : SUCCESS in 3m 40s Patch-set: 1 Tag: autogenerated:zuul:check Label: Verified=+1		2020-04-20 07:20:04 +00:00