Support Vitrage resources in Heat

The purpose is to automate the auto-healing process that
involves external monitoring, Vitrage alarm deduction and
Mistral workflow execution.

Story: 2002684
Task: 22527

Depends-On: Ie28ba2087c6d87aec57198afe9c328542a4c25ca
Change-Id: If66248e07a662a225799a2bd3fc88a31d1539021

specs/rocky/vitrage-resources.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
+
+=========================
+Support Vitrage Resources
+=========================
+
+https://storyboard.openstack.org/#!/story/2002684
+
+This Blueprint proposes to add support for Vitrage resources in Heat.
+The purpose is to automate the auto-healing process that involves external
+monitoring, Vitrage alarm deduction and Mistral workflow execution.
+
+Problem description
+===================
+
+Auto-healing a Heat stack when an instance is down is extremely important.
+This use case is already handled when Nova sends a notification about the
+instance state, Aodh raises an event alarm and as a result a Mistral healing
+workflow is executed.
+
+However, there are cases where Nova is not aware about the real state of the
+instance. One example is a network failure: a NIC that is down can result in no
+network connectivity to certain instances, while their state in Nova remains
+'Active'. We would like to support auto-healing in such cases as well.
+
+Proposed change
+===============
+
+An OS::Vitrage::Template resource will be added in Heat, under
+heat/engine/resources/openstack/vitrage.
+
+Its role will be to create, based on the properties given in HOT template,
+a Vitrage template with a condition->action scenario that will handle the
+healing.
+
+The VitrageTemplate resource will support the following use case:
+
+#. An external monitor detects a network failure
+#. Vitrage is notified, and based on its topology-graph it identifies all
+   affected resources
+#. If an instance that belongs to a Heat stack is affected, Vitrage executes
+   a Mistral healing workflow
+
+The VitrageTemplate definition:
+
+.. code-block:: yaml
+
+   resources:
+     name:
+       type: OS::Vitrage::Template
+       properties:
+         description: String
+         alarm_name: String
+         stack_id: String
+         workflow_id: String
+         workflow_input: {...}
+
+
+Properties:
+
+ - description - Description of the Vitrage template
+ - alarm_name - The name of the alarm that should trigger the workflow
+   execution. This can be an alarm from an external monitor (like Zabbix,
+   Nagios, Collectd, or Prometheus), or a deduced alarm that was raised by
+   Vitrage.
+ - workflow_id - Id of the Mistral workflow to be executed
+ - workflow_input - values to be passed as inputs to the workflow
+
+
+Example:
+
+.. code-block:: yaml
+
+   resources:
+     execute_healing:
+       type: OS::Vitrage::Template
+       properties:
+         description: Execute Mistral healing workflow if the instance is down
+         alarm_name: Instance down
+         stack_id: {get_param: "OS::stack_id"}
+         workflow_id: auto_heal
+         workflow_input:
+           heat_stack_id: {get_param: "OS::stack_id"}
+
+
+The implementation will be done in two phases.
+
+**Phase 1:** A simple Vitrage template will be created with and will support
+the following scenario:
+
+If an alarm named input_alarm_name is raised **on an instance that is part of
+the given Heat stack** -> execute the Mistral workflow
+
+**Phase 2:** We should enable creation of more complex Vitrage templates, like
+the one in the network failure use case. This will require additional
+development in Vitrage, so it will provide "template skeletons" for different
+scenarios.
+
+
+Alternatives
+------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  ifat_afek
+
+Milestones
+----------
+
+Target Milestone for completion:
+  rocky-3
+
+Work Items
+----------
+
+Phase 1:
+
+- Implement the VitrageTemplate resource
+- Add unit tests and tempest tests
+- Add a HOT template example to heat-templates
+
+Phase 2 (future):
+
+- Create different types of Vitrage templates
+
+Dependencies
+============
+
+No dependencies for phase 1.
+Phase 2 depends on future Vitrage development.