Adding upgrade with os upgrade graphics.

Change-Id: I02b2fa916792f20536af92a94e8e685d4777dace
Implements: blueprint upgrades-with-os
Co-Authored-By: Jiri Stransky <jistr@redhat.com>

doc/source/upgrade/developer/upgrades/major_upgrade_with_os.plantuml

@@ -0,0 +1,214 @@
+' The png image can be generated by running:
+'
+'     plantuml major_upgrade_with_os.plantuml
+
+@startuml
+
+actor User
+participant "undercloud"
+participant "controller-0"
+participant "controller-1"
+participant "controller-2"
+
+' === PREPARE ===
+
+note left of undercloud #AAFFAA
+    If controllers == 1, env file
+    is given to prefer `persist/restore`
+    instead of `transfer` for MariaDB.
+end note
+User -> "undercloud" : openstack overcloud upgrade prepare
+note right
+         Update heat outputs using latest templates.
+end note
+User <-- "undercloud"
+
+' === REPROVISION ===
+
+User -> "controller-0" : openstack overcloud upgrade run\n --tags system-upgrade-prepare \n --playbook upgrade-playbook.yml \n --node controller-0
+note right
+         Persist data from the bootstrap node
+         while it is live.
+         (Fetch the data to the undercloud.)
+         - if controllers == 1:
+           mariadb and other data (composable)
+         - if controllers > 1:
+           only other data (composable)
+end note
+
+"undercloud" <- "controller-0"
+note left: /var/lib/mistral/tripleo-persist/
+User <-- "controller-0"
+
+User -> "controller-0" : openstack server rebuild controller-0
+note right
+         Reprovision to the new OS.
+end note
+
+User <-- "controller-0"
+
+User -> "controller-0" : openstack overcloud upgrade prepare\n(or enable-ssh-admin.sh, will be improved upon)
+note right
+         Install Mistral ssh keys
+end note
+
+User <-- "controller-0"
+
+User -> "controller-0" : openstack overcloud upgrade run\n --tags system-upgrade-run \n --playbook upgrade-playbook.yml \n --node controller-0
+note right
+         Restore the data onto bootstrap node.
+         (Push the data from the undercloud.)
+         - if controllers == 1:
+           mariadb and other data (composable)
+         - if controllers > 1:
+           only other data (composable)
+end note
+
+User <-- "controller-0"
+
+' === TRANSFER DATA ===
+
+group Transfer the data to the freshly re-installed controller\n(only required in multi-controller environments)
+note over "undercloud", "controller-2" #AAFFAA
+    Everything is composable, but diagram showcases MariaDB specifically
+end note
+User -> "undercloud" : openstack overcloud external-upgarde run
+"undercloud" -> "controller-1" : pcs resource disable\ngalera-bundle
+note right: Disable MariaDB
+"controller-1" -> "controller-2"
+note right: Disable MariaDB
+
+note over undercloud, "controller-2" #FFAAAA
+     control plane outage.
+end note
+
+
+"undercloud" -> "controller-1" : transfer module run in ansible
+note right
+        Transfer data:
+        - if controllers == 1:
+          nothing
+        - if controllers > 1:
+          mysql data
+end note
+
+"controller-1" -> "undercloud": get the data
+note left: /var/lib/mistral/tripleo-transfer/
+User <-- "controller-1"
+
+"undercloud" -> "controller-0": push the data
+note right
+    extract the data
+end note
+
+User <-- "undercloud"
+end
+
+' === START CONTROLLER 0 ===
+
+"User" -> "controller-0": openstack overcloud upgrade run --nodes controller-0
+note right
+     Configure OpenStack,
+     start a new cluster.
+     (1 node total)
+end note
+
+note over undercloud, "controller-2" #FFAAAA
+     controller-0 is a one node cluster running the latest version
+     of tripleo on the new os.
+     The controller plane is back.
+end note
+
+User <-- "controller-0"
+
+' === ADD CONTROLLER 1 ===
+
+User -> "controller-1" : openstack overcloud upgrade run\n --tags system-upgrade-prepare \n --playbook upgrade-playbook.yml \n --node controller-1
+note right
+         Persist data
+         (composable)
+end note
+
+"undercloud" <- "controller-1"
+note left: /var/lib/mistral/tripleo-persist/
+
+User -> "controller-1" : openstack server rebuild controller-1
+note right
+        Reprovision to the new OS.
+end note
+
+User <-- "controller-1"
+
+User -> "controller-1" : openstack overcloud upgrade prepare\n(os oc reprovision ssh-admin)
+note right
+         Install Mistral ssh keys
+end note
+
+User <-- "controller-1"
+
+User -> "controller-1" : openstack overcloud upgrade run\n --tags system-upgrade-run \n --playbook upgrade-playbook.yml \n --nodes controller-1
+note right
+         Restore data
+         (composable)
+end note
+
+User <-- "controller-1"
+
+"User" -> "controller-1": openstack overcloud upgrade run --nodes controller-0,controller-1
+"User" -> "controller-0":
+note right of "controller-1"
+     Configure OpenStack,
+     join the cluster.
+     (2 nodes total)
+end note
+
+User <-- "controller-1"
+
+' === ADD CONTROLLER 2 ===
+
+User -> "controller-2" : openstack overcloud upgrade run\n --tags system-upgrade-prepare \n --playbook upgrade-playbook.yml \n --node controller-2
+note right
+         Persist data
+         (composable)
+end note
+
+"undercloud" <- "controller-2"
+note left: /var/lib/mistral/tripleo-persist/
+User <-- "controller-2"
+
+User -> "controller-2" : openstack server rebuild controller-2
+note right
+    Reprovision
+    to the new OS.
+end note
+
+User <-- "controller-2"
+
+User -> "controller-2" : openstack overcloud upgrade prepare\n(os oc reprovision ssh-admin)
+note right
+         Install Mistral
+         ssh keys
+end note
+
+User <-- "controller-2"
+
+User -> "controller-2" : openstack overcloud upgrade run\n --tags system-upgrade-run \n --playbook upgrade-playbook.yml \n --nodes controller-2
+note right
+        Restore data
+        (composable)
+end note
+
+User <-- "controller-2"
+
+"User" -> "controller-2": openstack overcloud upgrade run --nodes controller-0,controller-1,controller-2
+"User" -> "controller-1":
+"User" -> "controller-0":
+note right of "controller-2"
+     Configure OpenStack,
+     join the cluster.
+     (3 nodes total)
+end note
+
+User <-- "controller-2"
+
+@enduml