Add Usage Scenarios Examples to Capacity Management Story

Change-Id: Iea9ae46daab9190b086b37f16ff507431f831b30

user-stories/proposed/capacity_management.rst

@@ -145,7 +145,74 @@ Usage Scenarios Examples
 .. 1. Usage Scenario Title a. 1st Step b. 2nd Step 2. Usage Scenario Title a. 1st
 .. Step b. 2nd Step 3. [...]
 
-TBD
+1. Reserve resources for upcoming events
+
+   a. `Wei the project owner of a Telco operator`_ is in charge of network
+      planning for big events, like mega-concerts and festival, where local
+      traffic spikes are expected.
+   b. In order to ensure sufficient network capacity for the upcoming Fuji Rock
+      Festival on 22-24 July 2017, Wei reserves additional capacity by creating
+      a RUR which describes the aforementioned dates and the amount of
+      additional resources, e.g., 4 instances with 1 vCPU, 1GB of RAM, 10GB of
+      disk, and a guaranteed minimum bandwidth of 1Gbps between the instances
+      which are required for scaling the service.
+   c. After the RUR having successfully processed, Wei is acknowledged that the
+      appropriate resource is reserved for the event dates.
+
+2. Reserve resources for maintenance works
+
+   a. Wei is responsible for updating his services and
+      `Rey the cloud operator`_ is responsible for maintaining the underlying
+      cloud environment including its hardware. Now, the team plans a
+      maintenance window for several compute hosts on next Monday.
+   b. To avoid impact on the service, Wei plans to migrate all VMs running on
+      those hosts to other hosts that are not affected by the maintenance work
+      on Sunday, i.e., a day before the maintenance window.
+   c. In order to ensure that those other hosts are available from Sunday to the
+      end of the maintenance window, Wei reserves the required resources
+      through his frontend tools.
+   d. In the backend, the system creates respective RURs for this time window
+      to guarantee the availability of the resources and the system returns a
+      reservation ID to Wei.
+   e. On Sunday, Wei triggers the migration of the affected VMs referring to
+      the reservation ID. Rey then triggers the maintenance work on the cloud.
+      The work can be finished earlier than expected and after having migrated
+      back the VMs, Wei can release the reservation ahead of the planned
+      reservation end time.
+
+3. Reserve resources for disaster recovery
+
+   a. Wei is in charge of ensuring core services are running in disaster cases.
+      In order to be able to immediately react to a disaster situation, the
+      services maintains a disaster configuration for its core services and
+      keeps respective resources reserved for such situations.
+   b. Just now, an earthquake has hit the country and an automated tsunami
+      warning was issued by the government. Wei has a short time window to
+      prepare for the tsunami hitting the coastlines and its effects, e.g. a
+      high volume of extraordinary communication such as emergency
+      communication, evacuation instructions, and safety confirmations.
+   c. Wei switches the service to a pre-configured disaster configuration.
+      Switching to the disaster configuration is supported by resources that
+      had been exclusively reserved for such situations.
+
+4. Reserve resources for launching new services
+
+   a. Wei is in charge of introducing a new service that has complex
+      requirements on the infrastructure resources. In order to avoid the risk
+      that one requirement during the allocation of the resources cannot be met
+      and the allocation of resources has to be rolled back or be changed to
+      meet the requirements, Wei first creates a reservation for the required
+      resources specifying in the request also all parameters and conditions
+      the resources have to fulfil.
+   b. The reservation service tries to reserve the resources with the specified
+      criteria. After having successfully created the reservation, a reservation
+      ID is returned to Wei.
+   c. Wei then triggers the setup of the service referencing the reservation ID
+      knowing that all resource requirements can be met. The new service is
+      initialized without conflicts.
+
+.. _Wei the project owner of a Telco operator: http://docs.openstack.org/contributor-guide/ux-ui-guidelines/ux-personas/project-owner.html
+.. _Rey the cloud operator: http://docs.openstack.org/contributor-guide/ux-ui-guidelines/ux-personas/cloud-ops.html
 
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