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+****************
+Design Documents
+****************
+
+This is the directory to store design documents which may include draft
+versions of blueprints written before proposing to upstream OSS communities
+such as OpenStack, in order to keep the original blueprint as reviewed in
+OPNFV. That means there could be out-dated blueprints as result of further
+refinements in the upstream OSS community. Please refer to the link in each
+document to find the latest version of the blueprint and status of development
+in the relevant OSS community.
+
+See also https://wiki.opnfv.org/requirements_projects .
+
+.. toctree::
+ :numbered:
+ :maxdepth: 4
+
+ report-host-fault-to-update-server-state-immediately.rst
+ notification-alarm-evaluator.rst
diff --git a/docs/design/notification-alarm-evaluator.rst b/docs/design/notification-alarm-evaluator.rst
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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+============================
+Notification Alarm Evaluator
+============================
+
+.. NOTE::
+ This is spec draft of brlueprint for OpenStack Ceilomter Liberty.
+ To see current version: https://review.openstack.org/172893
+ To track development activity:
+ https://blueprints.launchpad.net/ceilometer/+spec/notification-alarm-evaluator
+
+https://blueprints.launchpad.net/ceilometer/+spec/notification-alarm-evaluator
+
+This blueprint proposes to add a new alarm evaluator for handling alarms on
+events passed from other OpenStack services, that provides event-driven alarm
+evaluation which makes new sequence in Ceilometer instead of the polling-based
+approach of the existing Alarm Evaluator, and realizes immediate alarm
+notification to end users.
+
+Problem description
+===================
+
+As an end user, I need to receive alarm notification immediately once
+Ceilometer captured an event which would make alarm fired, so that I can
+perform recovery actions promptly to shorten downtime of my service.
+The typical use case is that an end user set alarm on "compute.instance.update"
+in order to trigger recovery actions once the instance status has changed to
+'shutdown' or 'error'. It should be nice that an end user can receive
+notification within 1 second after fault observed as the same as other helth-
+check mechanisms can do in some cases.
+
+The existing Alarm Evaluator is periodically querying/polling the databases
+in order to check all alarms independently from other processes. This is good
+approach for evaluating an alarm on samples stored in a certain period.
+However, this is not efficient to evaluate an alarm on events which are emitted
+by other OpenStack servers once in a while.
+
+The periodical evaluation leads delay on sending alarm notification to users.
+The default period of evaluation cycle is 60 seconds. It is recommended that
+an operator set longer interval than configured pipeline interval for
+underlying metrics, and also longer enough to evaluate all defined alarms
+in certain period while taking into account the number of resources, users and
+alarms.
+
+Proposed change
+===============
+
+The proposal is to add a new event-driven alarm evaluator which receives
+messages from Notification Agent and finds related Alarms, then evaluates each
+alarms;
+
+* New alarm evaluator could receive event notification from Notification Agent
+ by which adding a dedicated notifier as a publisher in pipeline.yaml
+ (e.g. notifier://?topic=event_eval).
+
+* When new alarm evaluator received event notification, it queries alarm
+ database by Project ID and Resource ID written in the event notification.
+
+* Found alarms are evaluated by referring event notification.
+
+* Depending on the result of evaluation, those alarms would be fired through
+ Alarm Notifier as the same as existing Alarm Evaluator does.
+
+This proposal also adds new alarm type "notification" and "notification_rule".
+This enables users to create alarms on events. The separation from other alarm
+types (such as "threshold" type) is intended to show different timing of
+evaluation and different format of condition, since the new evaluator will
+check each event notification once it received whereas "threshold" alarm can
+evaluate average of values in certain period calculated from multiple samples.
+
+The new alarm evaluator handles Notification type alarms, so we have to change
+existing alarm evaluator to exclude "notification" type alarms from evaluation
+targets.
+
+Alternatives
+------------
+
+There was similar blueprint proposal "Alarm type based on notification", but
+the approach is different. The old proposal was to adding new step (alarm
+evaluations) in Notification Agent every time it received event from other
+OpenStack services, whereas this proposal intends to execute alarm evaluation
+in another component which can minimize impact to existing pipeline processing.
+
+Another approach is enhancement of existing alarm evaluator by adding
+notification listener. However, there are two issues; 1) this approach could
+cause stall of periodical evaluations when it receives bulk of notifications,
+and 2) this could break the alarm portioning i.e. when alarm evaluator received
+notification, it might have to evaluate some alarms which are not assign to it.
+
+Data model impact
+-----------------
+
+Resource ID will be added to Alarm model as an optional attribute.
+This would help the new alarm evaluator to filter out non-related alarms
+while querying alarms, otherwise it have to evaluate all alarms in the project.
+
+REST API impact
+---------------
+
+Alarm API will be extended as follows;
+
+* Add "notification" type into alarm type list
+* Add "resource_id" to "alarm"
+* Add "notification_rule" to "alarm"
+
+Sample data of Notification-type alarm::
+
+ {
+ "alarm_actions": [
+ "http://site:8000/alarm"
+ ],
+ "alarm_id": null,
+ "description": "An alarm",
+ "enabled": true,
+ "insufficient_data_actions": [
+ "http://site:8000/nodata"
+ ],
+ "name": "InstanceStatusAlarm",
+ "notification_rule": {
+ "event_type": "compute.instance.update",
+ "query" : [
+ {
+ "field" : "traits.state",
+ "type" : "string",
+ "value" : "error",
+ "op" : "eq",
+ },
+ ]
+ },
+ "ok_actions": [],
+ "project_id": "c96c887c216949acbdfbd8b494863567",
+ "repeat_actions": false,
+ "resource_id": "153462d0-a9b8-4b5b-8175-9e4b05e9b856",
+ "severity": "moderate",
+ "state": "ok",
+ "state_timestamp": "2015-04-03T17:49:38.406845",
+ "timestamp": "2015-04-03T17:49:38.406839",
+ "type": "notification",
+ "user_id": "c96c887c216949acbdfbd8b494863567"
+ }
+
+"resource_id" will be refered to query alarm and will not be check permission
+and belonging of project.
+
+Security impact
+---------------
+
+None
+
+Pipeline impact
+---------------
+
+None
+
+Other end user impact
+---------------------
+
+None
+
+Performance/Scalability Impacts
+-------------------------------
+
+When Ceilomter received a number of events from other OpenStack services in
+short period, this alarm evaluator can keep working since events are queued in
+a messaging queue system, but it can cause delay of alarm notification to users
+and increase the number of read and write access to alarm database.
+
+"resource_id" can be optional, but restricting it to mandatory could be reduce
+performance impact. If user create "notification" alarm without "resource_id",
+those alarms will be evaluated every time event occurred in the project.
+That may lead new evaluator heavy.
+
+Other deployer impact
+---------------------
+
+New service process have to be run.
+
+Developer impact
+----------------
+
+Developers should be aware that events could be notified to end users and avoid
+passing raw infra information to end users, while defining events and traits.
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+ r-mibu
+
+Other contributors:
+ None
+
+Ongoing maintainer:
+ None
+
+Work Items
+----------
+
+* New event-driven alarm evaluator
+
+* Add new alarm type "notification" as well as AlarmNotificationRule
+
+* Add "resource_id" to Alarm model
+
+* Modify existing alarm evaluator to filter out "notification" alarms
+
+* Add new config parameter for alarm request check whether accepting alarms
+ without specifying "resource_id" or not
+
+Future lifecycle
+================
+
+This proposal is key feature to provide information of cloud resources to end
+users in real-time that enables efficient integration with user-side manager
+or Orchestrator, whereas currently those information are considered to be
+consumed by admin side tool or service.
+Based on this change, we will seek orchestrating scenarios including fault
+recovery and add useful event definition as well as additional traits.
+
+Dependencies
+============
+
+None
+
+Testing
+=======
+
+New unit/scenario tests are required for this change.
+
+Documentation Impact
+====================
+
+* Proposed evaluator will be described in the developer document.
+
+* New alarm type and how to use will be explained in user guide.
+
+References
+==========
+
+* OPNFV Doctor project: https://wiki.opnfv.org/doctor
+
+* Blueprint "Alarm type based on notification":
+ https://blueprints.launchpad.net/ceilometer/+spec/alarm-on-notification
diff --git a/docs/design/report-host-fault-to-update-server-state-immediately.rst b/docs/design/report-host-fault-to-update-server-state-immediately.rst
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+====================================================
+Report host fault to update server state immediately
+====================================================
+
+https://blueprints.launchpad.net/nova/+spec/update-server-state-immediately
+
+A new API is needed to report a host fault to change the state of the
+instances and compute node immediately. This allows usage of evacuate API
+without a delay. The new API provides the possibility for external monitoring
+system to detect any kind of host failure fast and reliably and inform
+OpenStack about it. Nova updates the compute node state and states of the
+instances. This way the states in the Nova DB will be in sync with the
+real state of the system.
+
+Problem description
+===================
+* Nova state change for failed or unreachable host is slow and does not
+ reliably state compute node is down or not. This might cause same instance
+ to run twice if action taken to evacuate instance to another host.
+* Nova state for instances on failed compute node will not change,
+ but remains active and running. This gives user a false information about
+ instance state. Currently one would need to call "nova reset-state" for each
+ instance to have them in error state.
+* OpenStack user cannot make HA actions fast and reliably by trusting instance
+ state and compute node state.
+* As compute node state changes slowly one cannot evacuate instances.
+
+Use Cases
+---------
+Use case in general is that in case there is a host fault one should change
+compute node state fast and reliably when using DB servicegroup backend.
+On top of this here is the use cases that are not covered currently to have
+instance states changed correctly:
+* Management network connectivity lost between controller and compute node.
+* Host HW failed.
+
+Generic use case flow:
+
+* The external monitoring system detects a host fault.
+* The external monitoring system fences the host if not down already.
+* The external system calls the new Nova API to force the failed compute node
+ into down state as well as instances running on it.
+* Nova updates the compute node state and state of the effected instances to
+ Nova DB.
+
+Currently nova-compute state will be changing "down", but it takes a long
+time. Server state keeps as "vm_state: active" and "power_state:
+running", which is not correct. By having external tool to detect host faults
+fast, fence host by powering down and then report host down to OpenStack, all
+these states would reflect to actual situation. Also if OpenStack will not
+implement automatic actions for fault correlation, external tool can do that.
+This could be configured for example in server instance METADATA easily and be
+read by external tool.
+
+Project Priority
+-----------------
+Liberty priorities have not yet been defined.
+
+Proposed change
+===============
+There needs to be a new API for Admin to state host is down. This API is used
+to mark compute node and instances running on it down to reflect the real
+situation.
+
+Example on compute node is:
+
+* When compute node is up and running:
+ vm_state: active and power_state: running
+ nova-compute state: up status: enabled
+* When compute node goes down and new API is called to state host is down:
+ vm_state: stopped power_state: shutdown
+ nova-compute state: down status: enabled
+
+vm_state values: soft-delete, deleted, resized and error
+should not be touched.
+task_state effect needs to be worked out if needs to be touched.
+
+Alternatives
+------------
+There is no attractive alternatives to detect all different host faults than
+to have a external tool to detect different host faults. For this kind of tool
+to exist there needs to be new API in Nova to report fault. Currently there
+must have been some kind of workarounds implemented as cannot trust or get the
+states from OpenStack fast enough.
+
+Data model impact
+-----------------
+None
+
+REST API impact
+---------------
+* Update CLI to report host is down
+
+ nova host-update command
+
+ usage: nova host-update [--status <enable|disable>]
+ [--maintenance <enable|disable>]
+ [--report-host-down]
+ <hostname>
+
+ Update host settings.
+
+ Positional arguments
+
+ <hostname>
+ Name of host.
+
+ Optional arguments
+
+ --status <enable|disable>
+ Either enable or disable a host.
+
+ --maintenance <enable|disable>
+ Either put or resume host to/from maintenance.
+
+ --down
+ Report host down to update instance and compute node state in db.
+
+* Update Compute API to report host is down:
+
+ /v2.1/{tenant_id}/os-hosts/{host_name}
+
+ Normal response codes: 200
+ Request parameters
+
+ Parameter Style Type Description
+ host_name URI xsd:string The name of the host of interest to you.
+
+ {
+ "host": {
+ "status": "enable",
+ "maintenance_mode": "enable"
+ "host_down_reported": "true"
+
+ }
+
+ }
+
+ {
+ "host": {
+ "host": "65c5d5b7e3bd44308e67fc50f362aee6",
+ "maintenance_mode": "enabled",
+ "status": "enabled"
+ "host_down_reported": "true"
+
+ }
+
+ }
+
+* New method to nova.compute.api module HostAPI class to have a
+ to mark host related instances and compute node down:
+ set_host_down(context, host_name)
+
+* class novaclient.v2.hosts.HostManager(api) method update(host, values)
+ Needs to handle reporting host down.
+
+* Schema does not need changes as in db only service and server states are to
+ be changed.
+
+Security impact
+---------------
+API call needs admin privileges (in the default policy configuration).
+
+Notifications impact
+--------------------
+None
+
+Other end user impact
+---------------------
+None
+
+Performance Impact
+------------------
+Only impact is that user can get information faster about instance and
+compute node state. This also gives possibility to evacuate faster.
+No impact that would slow down. Host down should be rare occurrence.
+
+Other deployer impact
+---------------------
+Developer can make use of any external tool to detect host fault and report it
+to OpenStack.
+
+Developer impact
+----------------
+None
+
+Implementation
+==============
+Assignee(s)
+-----------
+Primary assignee: Tomi Juvonen
+Other contributors: Ryota Mibu
+
+Work Items
+----------
+* Test cases.
+* API changes.
+* Documentation.
+
+Dependencies
+============
+None
+
+Testing
+=======
+Test cases that exists for enabling or putting host to maintenance should be
+altered or similar new cases made test new functionality.
+
+Documentation Impact
+====================
+
+New API needs to be documented:
+
+* Compute API extensions documentation.
+ http://developer.openstack.org/api-ref-compute-v2.1.html
+* Nova commands documentation.
+ http://docs.openstack.org/user-guide-admin/content/novaclient_commands.html
+* Compute command-line client documentation.
+ http://docs.openstack.org/cli-reference/content/novaclient_commands.html
+* nova.compute.api documentation.
+ http://docs.openstack.org/developer/nova/api/nova.compute.api.html
+* High Availability guide might have page to tell external tool could provide
+ ability to provide faster HA as able to update states by new API.
+ http://docs.openstack.org/high-availability-guide/content/index.html
+
+References
+==========
+* OPNFV Doctor project: https://wiki.opnfv.org/doctor
+* OpenStack Instance HA Proposal:
+ http://blog.russellbryant.net/2014/10/15/openstack-instance-ha-proposal/
+* The Different Facets of OpenStack HA:
+ http://blog.russellbryant.net/2015/03/10/
+ the-different-facets-of-openstack-ha/