openstack/monasca-specs
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Monasca Events Publishing Spec

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Monasca Events API was developed to store events
data in Elasticsearch.

There is still a need to collect and publish
Openstack Notifications as Monasca Events.

This commit includes a specification for creating a new Monasca
Events Listener service that would be independent of Ceilometer.
This is being proposed for the Stein cycle.

Monasca Ceilometer project currently publishes ceilometer samples
to Monasca API. An alternate specification proposes to extend Monasca
Ceilometer project and add a new events publisher which would publish
Openstack notifications (or events) to Monasca Events API.
This solution was proposed for Rocky but will not be implemented
as the Ceilometer Events feature has been deprecated on master.

Co-Authored-By: Joseph Davis <joseph.davis@suse.com>
Co-Authored-By: Ashwin Agate <ashwin.agate@suse.com>

Story: 2003023
Task: 23047

Change-Id: I8ed7a19c0565a0cd613866934eb2540ae46c847d
This commit is contained in:
Ashwin Agate 2018-07-18 17:54:40 -07:00 committed by Joseph Davis
parent 819eeb8fa5
commit f01ecbb9ad
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README.rst
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@ -25,11 +25,14 @@ The layout of this repository is::
priorities/<release>/
specs/<release>/
Where there are two sub-directories in ``specs``:
Where there are three sub-directories in ``specs``:
specs/<release>/approved
specifications approved, but not yet implemented
Specifications approved, but not yet implemented
specs/<release>/implemented
implemented specifications
Implemented specifications
specs/<release>/not-implemented
Specifications that were approved but are not expected to be implemented.
These are kept for historical reference.

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doc/source/specs/rocky/index.rst
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@ -24,3 +24,11 @@ Rocky approved (but not implemented) specs:
:maxdepth: 1
approved/*
Rocky deprecated specs:
.. toctree::
:glob:
:maxdepth: 1
not-implemented/*

1
doc/source/specs/rocky/not-implemented Symbolic link
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../../../../specs/rocky/not-implemented

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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
================================================
Monasca Events Publishing - from Ceilometer
================================================
https://storyboard.openstack.org/#!/story/2003023
Monasca Events API [1] was developed to store Openstack Notification data in Elasticsearch. There is
still a need to collect and publish Openstack Notifications to Monasca Events API. Monasca
Ceilometer project[2] currently publishes ceilometer samples[3] to Monasca API. We are proposing to
extend Monasca Ceilometer project and add a new events publisher which will publish Openstack
notifications (or events)[3] to Monasca Events API.
UPDATE: This spec is being superceded by the ../../stein/approved/monasca-events-listener.rst spec,
but is kept here for reference.
Problem description
===================
All Openstack services generate a lot of notifications or events which contain large amounts of
operational and state information about the service and its resources. This notification data is not
currently available in Monasca.
Ceilometer data processing pipeline[3] provides an extensible mechanism of publishing samples and
events using a custom publisher. Ceilometer samples represent a quantity that can be measured (for
e.g. the size of a volume) and events represent an occurrence of an event and do not have any
associated quantity (e.g. volume was created).
Monasca Ceilometer project currently provides a samples publisher. Monasca Ceilometer samples
publisher converts Ceilometer samples to Monasca Metrics format which are then published to Monasca
API. There is no corresponding events publisher to Monasca yet.
By adding an event publisher to Monasca Ceilometer project we could take advantage of Ceilometer's
event publishing mechanism to publish events to Monasca Events API.
Ceilometer consists of different data collection components - namely Polling Agent, Notification
Agent and Compute Agent. (Please see [7] for System Architecture diagram) Ceilometer also has a data
storage and retrieval component, which would be Monasca in our case.
Samples publisher and new proposed events publisher run within Ceilometer's Notification Agent
component and are part of Notifcation Agent's data processing pipeline. Monasca
Ceilometer presumes the need to install and deploy Ceilometer Notification Agent component (doesn't
need Polling Agent or Compute Agent deployed) on all the control nodes. Ceilometer Notification
Agent is Highly Available (HA) and can run on multiple nodes. We will have to evaluate its
performance in terms of scaling for events, but we haven't run into performance/scale problems
with current samples publisher.
Use Cases
---------
#. Openstack notification data would be stored in Elasticsearch
via the Monasca Events API
Example sequence from Nova notification to Monasca API
#. Nova completes the creation of a VM
#. Nova generates a Notification message to oslo.messaging
#. Ceilometer Notification agent receives the Notification message
#. Ceilometer translates the Notification to a Monasca API format according to the configuration
#. Ceilometer Event Publisher publishes formatted Notification to Monasca Events API
#. Monasca Events API receives and validates formatted Notification
#. Monasca Events stores event Notification in configured Elasticsearch instance
Proposed change
===============
#. Openstack Notifications consist of envelope and payload fields
Example Openstack Notification data format:
.. code-block:: javascript
{
"_context_auth_token": "42630b3ea13242fcad20e0a92d0207f1",
"_context_domain": null,
"_context_instance_lock_checked": false,
"_context_is_admin": true,
"_context_project_domain": null,
"_context_project_id": "a4f77",
"_context_project_name": "admin",
"_context_quota_class": null,
"_context_read_deleted": "no",
"_context_read_only": false,
"_context_remote_address": "192.168.245.4",
"_context_request_id": "req-5948338c-f223-4fd8-9249-8769f7a3e460",
"_context_resource_uuid": null,
"_context_roles": [
"monasca-user",
"admin",
"KeystoneAdmin"
],
"_context_service_catalog": [
{
"endpoints": [
{
"adminURL": "http://192.168.245.8:8776/v2/a4f77",
"internalURL": "http://192.168.245.8:8776/v2/a4f77",
"publicURL": "http://192.168.245.9:8776/v2/a4f77",
"region": "region1"
}
],
"name": "cinderv2",
"type": "volumev2"
},
{
"endpoints": [
{
"adminURL": "http://192.168.245.8:8776/v1/a4f77",
"internalURL": "http://192.168.245.8:8776/v1/a4f77",
"publicURL": "http://192.168.245.9:8776/v1/a4f77",
"region": "region1"
}
],
"name": "cinder",
"type": "volume"
}
],
"_context_show_deleted": false,
"_context_tenant": "a4f77",
"_context_timestamp": "2015-09-18T20:54:23.468522",
"_context_user": "be396488c7034811a200a3cb1d103a28",
"_context_user_domain": null,
"_context_user_id": "be396488c7034811a200a3cb1d103a28",
"_context_user_identity": "be396488c7034811a200a3cb1d103a28 a4f77 - - -",
"_context_user_name": "admin",
"_unique_id": "ff9699d587bf4283a3c367ab88be1541",
"event_type": "compute.instance.create.start",
"message_id": "c6149ba1-34b3-4367-b8c2-b1d6f073742d",
"payload": {
"access_ip_v4": null,
"access_ip_v6": null,
"architecture": null,
"availability_zone": null,
"cell_name": "",
"created_at": "2015-09-18 20:55:25+00:00",
"deleted_at": "",
"disk_gb": 1,
"display_name": "testeee",
"ephemeral_gb": 0,
"host": null,
"hostname": "testeee",
"image_meta": {
"base_image_ref": "df0c8",
"container_format": "bare",
"disk_format": "qcow2",
"min_disk": "1",
"min_ram": "0"
},
"image_name": "glanceaaa3",
"image_ref_url": "http://192.168.245.5:9292/images/df0c8",
"instance_flavor_id": "1",
"instance_id": "abd2ef5c-0381-434a-8efc-d7b39b28a2b6",
"instance_type": "m1.tiny",
"instance_type_id": 4,
"kernel_id": "",
"launched_at": "",
"memory_mb": 512,
"metadata": {},
"node": null,
"os_type": null,
"progress": "",
"ramdisk_id": "",
"reservation_id": "r-1ghilddw",
"root_gb": 1,
"state": "building",
"state_description": "",
"tenant_id": "a4f77",
"terminated_at": "",
"user_id": "be396488c7034811a200a3cb1d103a28",
"vcpus": 1
},
"priority": "INFO",
"publisher_id": "compute.ccp-compute0001-mgmt",
"timestamp": "2015-09-18 20:55:37.639023"
}
#. All the fields with the prefix of '_context" are the envelope fields, the
other interesting fields are
#. 'message_id' - notification identifier
#. 'payload' - contains most of the relevant and useful information in JSON format
#. 'priority' - notification priority
#. 'publisher_id' - notification publisher
#. 'timestamp' - notification timestamp
#. Ceilometer event publishing framework converts the Openstack notifications to events format[4].
Event publishing framework also has the ability to extract only some of the 'payload' data into
a flat set of key-value pairs called 'traits' and publish the normalized 'event' with 'traits'
extracted from the payload using a custom publisher.
Extraction of certain fields into traits from the payload is
driven by configuration file, but by default "publisher_id",
'request_id', 'tenant_id', 'user_id' and 'project_id'
fields are always extracted and added as 'traits'.
The event can also have an optional field called 'raw' which has original
notification, provided 'store_raw' option is set in ceilometer.conf
Questions/TODO:
* Q1: Does the store_raw field only apply to events, or to all notifications processed by
Ceilometer?
* We will have to find it out if it has any adverse impact on sample publisher. Though in the
case of samples, monasca sample publisher definitely does not submit raw payload, so it must
be getting dropped.
Example Ceilometer Event data format:
.. code-block:: javascript
{
"event_type": "compute.instance.create.start",
"message_id": "c6149ba1-34b3-4367-b8c2-b1d6f073742d",
"generated": "2015-09-18 20:55:37.639023",
"traits": {
"publisher_id": "compute.ccp-compute0001-mgmt",
"request_id": "req-5948338c-f223-4fd8-9249-8769f7a3e460",
"tenant_id": "a4f77",
"project_id": "a4f77",
"user_id": "be396488c7034811a200a3cb1d103a28"
},
"raw": { "_context_auth_token": "42630b3ea13242fcad20e0a92d0207f1",
"_context_domain": null,
...
...
"event_type": "compute.instance.create.start",
"message_id": "c6149ba1-34b3-4367-b8c2-b1d6f073742d",
"payload": {
"access_ip_v4": null,
"access_ip_v6": null,
"architecture": null,
"availability_zone": null,
"cell_name": "",
"created_at": "2015-09-18 20:55:25+00:00",
"deleted_at": "",
"disk_gb": 1,
"display_name": "testeee",
"ephemeral_gb": 0,
"host": null,
"hostname": "testeee",
"image_meta": {
"base_image_ref": "df0c8",
"container_format": "bare",
"disk_format": "qcow2",
"min_disk": "1",
"min_ram": "0"
},
"image_name": "glanceaaa3",
"image_ref_url": "http://192.168.245.5:9292/images/df0c8",
"instance_flavor_id": "1",
"instance_id": "abd2ef5c-0381-434a-8efc-d7b39b28a2b6",
"instance_type": "m1.tiny",
"instance_type_id": 4,
"kernel_id": "",
"launched_at": "",
"memory_mb": 512,
"metadata": {},
"node": null,
"os_type": null,
"progress": "",
"ramdisk_id": "",
"reservation_id": "r-1ghilddw",
"root_gb": 1,
"state": "building",
"state_description": "",
"tenant_id": "a4f77",
"terminated_at": "",
"user_id": "be396488c7034811a200a3cb1d103a28",
"vcpus": 1
}
}
}
#. Key-Value pairs that can be extracted from 'payload' in form of traits
can be defined in events definitions file.
For example the following events definitions yaml specifies that for
all events which have a prefix of "compute.instance.*" then
add "user_id", "instance_id", and "instance_type_id" as traits,
after extracting values from "payload.user_id", "payload.instance_id",
and "payload.instance_type_id" respectively.
.. code-block:: yaml
---
- event_type: compute.instance.*
traits: &instance_traits
user_id:
fields: payload.user_id
instance_id:
fields: payload.instance_id
instance_type_id:
type: int
fields: payload.instance_type_id
We are for now proposing not to use this feature, of defining traits for each event
extracting since we have the ability to store entire payload, via
Monasca Events API.
We can certainly look at enabling this feature in the future if we run into trouble storing
entire JSON "payload" in Elasticsearch. This is certainly a nifty way to trim the amount
of data that will be stored.
#. The proposed new Custom Monasca Ceilometer event publisher will run within Ceilometer's
Notification Agent component. It will leverage Ceilometer's data processing pipeline[3] which
converts notifications to Ceilometer's event format. At the end of its processing, Monasca
Ceilometer event publisher will convert Ceilometer Event data into Monasca Event format[6] and
publish the monasca event to Monasca Events API.
#. Monasca Events API allows a field called 'payload' which can be in an arbitrary
nested JSON format. Monasca-Ceilometer event publisher will extract JSON field called
'payload' from 'raw' (JSON path notation: 'raw.payload'), publish the payload from the
original notification to Monasca Events API.
Example Monasca Event Format:
.. code-block:: javascript
events: [
{
dimensions": {
"service": "compute.ccp-compute0001-mgmt",
"topic": "notification.sample",
"hostname": "nova-compute:compute
},
event: {
"event_type": "compute.instance.create.start",
"payload": {
"access_ip_v4": null,
"access_ip_v6": null,
"architecture": null,
"availability_zone": null,
"cell_name": "",
"created_at": "2015-09-18 20:55:25+00:00",
"deleted_at": "",
"disk_gb": 1,
"display_name": "testeee",
"ephemeral_gb": 0,
"host": null,
"hostname": "testeee",
"image_meta": {
"base_image_ref": "df0c8",
"container_format": "bare",
"disk_format": "qcow2",
"min_disk": "1",
"min_ram": "0"
},
"image_name": "glanceaaa3",
"image_ref_url": "http://192.168.245.5:9292/images/df0c8",
"instance_flavor_id": "1",
"instance_id": "abd2ef5c-0381-434a-8efc-d7b39b28a2b6",
"instance_type": "m1.tiny",
"instance_type_id": 4,
"kernel_id": "",
"launched_at": "",
"memory_mb": 512,
"metadata": {},
"node": null,
"os_type": null,
"progress": "",
"ramdisk_id": "",
"reservation_id": "r-1ghilddw",
"root_gb": 1,
"state": "building",
"state_description": "",
"tenant_id": "a4f77",
"terminated_at": "",
"user_id": "be396488c7034811a200a3cb1d103a28",
"vcpus": 1
}
},
publisher_id: "compute.ccp-compute0001-mgmt",
priority: "INFO"
}
]
#. If no traits are specified in events pipeline yaml configuration file for an event
Ceilometer's data processing pipeline will add the following default traits:
* service: (All notifications should have this) notification’s publisher
* tenant_id
* request_id
* project_id
* user_id
Note: "service" is not the service that produced the event as in say "compute", "glance",
"cinder" but rather notification RabbitMQ publisher that produced the event
e.g. "compute.ccp-compute0001-mgmt" so is not very useful.
#. Ceilometer event data is converted to Monasca event data format before being published to Monasca
Event API. Following fields in Monasca Event data are not available in current Ceilometer Event
data format:
* "service"
* "dimensions.topic"
* "event.priority"
We are proposing removing these fields from Monasca Event format (will be done as a separate
spec/implementation process) for the following reasons:
"service": Currently Openstack notifications do not specify a service, that
generated the notification in a consistent way. It might be possible to create an external
mapping file which maps event name to a service but its hard to maintain such mapping over a
period of time.
"dimensions.topic": This field is not available in the source Openstack notification
"event.priority": This field is not currently available in Ceilometer Event format. It is
available in the source Openstack notification. Note: If we think this field can be useful we can
propose adding it to the Ceilometer Event format.
#. Following new fields will be added to Monasca Event data as dimensions:
* "dimensions.publisher_id": Identifier for the publisher that generated the event. Maps to
"traits.publisher_id" in Ceilometer event data.
* "dimensions.user_id": Identifier for user that generated the event. Maps to "traits.user_id" in
Ceilometer event data.
* "dimensions.project_id": Identifier of the project that generated the event. Maps to
"traits.project_id" or "traits.tenant_id" in Ceilometer event data.
#. hostname is available in the event payload, but its location might differ from event to event. We
can use Ceilometer's event definitions config to always add a trait called "hostname" to all
events. e.g. for compute.instance.* will have a trait called "hostname", which grabs data from
"payload.hostname"
.. code-block:: yaml
---
- event_type: compute.instance.*
traits: &instance_traits
user_id:
fields: payload.hostname
#. The proposed new Monasca Ceilometer event publisher will have the ability to submit event
data in a batch and at a configurable frequency (similar to current samples publisher). The
event data will be published if the items in the current batch reach their maximum size
(config setting) or if certain time interval has elapsed since the last publish
(config setting). This will make sure that the batch does not get huge at the same time
there is no significant delay in publishing of the events to Monasca Events API.
#. Monasca Ceilometer event publisher will use service credentials from ceilometer configuration
file (in "[monasca]" section) to get keystone token.
Example "[monasca]" section in ceilometer config file
.. code-block:: text
[monasca]
service_auth_url = https://localhost:5000/v3
service_password = secretpassword
service_username = ceilometer
service_interface = internalURL
service_auth_type = password
# service_project_id may also be used
service_project_name = admin
service_domain_name = Default
service_region_name = RegionOne
The publisher will then make a POST request to Monasca Events /v1.0/events REST api[8] to publish
events to Monasca Events API. The URL for the instance of Monasca Events API will be configured
in the Ceilometer 'events-pipeline.yaml' file. This has the added advantage of allowing
different events to be published differently (see Ceilometer pipeline documentation [10]).
#. "tenant_id" and "user_id" that the notification relates to are available in "payload" section
of the notification, and these notifications are generated by each service itself.
There is no additional "Openstack-operator-agent" like component or functionality required to
fetch that data from the service and publish to monasca event api on behalf of the original
tenant.
Ceilometer publishing pipeline simply extracts these "tenant_id" and "user_id" fields from the
"payload" and makes those fields available as "tenant_id" and "user_id" traits, which would then
be mapped to "dimensions.project_id" and "dimensions.user_id" fields in monasca events format.
In other words, original "tenant_id" and "user_id" values are available in
the payload of the notification, and will make its way to "dimensions.tenant_id"
and "dimensions.user_id" in Monasca Event.
Questions/TODO:
* Q: Do we need to do anything special to handle multi-tenancy in monasca-events api like being
done for metrics[9] ? Would original user_id and tenant_id in "dimensions.user_id" and
"dimensions.tenant_id" fields in dimensions serve this purpose?
* Q: In Ceilometer V2 API (which has been deprecated and removed), when querying data the role
"admin" could access data for all tenants, whereas a user with "ceilometer-admin" role could
access only data for a particular tenant. Can we implement something like this for
monasca-events api when querying for data?
#. Monasca Ceilometer event publisher will also retry submitting a batch, in case Monasca
Events API is temporarily unavailable or down. The retry frequency, the number of retries
and the number of items that can be in the retry batch will also be set via configuration.
Alternative Solutions
---------------------
#. Standalone monasca event agent which reads Openstack notifications published to RabbitMQ
(on "notification" topic) and publishes them to Monasca Events API.
Pro:
* No dependency on Telemetry project.
* May be simple to develop if leverage the oslo.messaging functionality.
* Ceilometer has *deprecated* the events functionality in the Stein release. [13]
Con:
* Another agent to convince users to install on their systems.
* Reinventing work already done in the Ceilometer agent. The OpenStack community already uses Ceilometer and contributes updates when something fails.
This alternate solution will be detailed in a separate spec, as it is likely
the long term solution Monasca will need.
#. Openstack Panko [5] is a event storage and REST API for Ceilometer.
Pro:
* An 'official' subproject within Telemetry, so there is some community recognition.
Con:
* Its primary storage is in a relational database which has problems with scale.
* It is not maintained actively and not ready for production. [11]
* It will be deprecated eventually. [12]
Data model impact
-----------------
None
REST API impact
---------------
#. We are proposing to tweak the Monasca Event data format by removing and adding following
fields as mentioned in "Proposed change" section above.
Remove fields (JSON path notation): "service", "dimensions.topic",
"dimensions.hostname" and "event.priority"
Add fields (JSON path notation): "dimensions.publisher_id", "dimensions.user_id" and
"dimensions.project_id"
This change will have an impact on Monasca Events API.
Security impact
---------------
The proposed Monasca Ceilometer events publisher will collect and publish
Openstack event (notification) data to Monasca API. Openstack notification
data does not have any sensitive data like 'tokens'.
Notifications do contain 'user_id' and 'project_id' fields but do not
contain any Personally Identifiable Information (PII) for the user or
the project.
Other end user impact
---------------------
None.
Performance Impact
------------------
#. The number of notifications(events) generated by different services will depend on the capacity
of the cloud along with the number of resources being created by the users.
For example, if there was a large number of compute VM's being created or destroyed it could
lead to a surge in number of notifications (events) that would have to be published. Optimum
configuration options related to say event batch size and event batch interval would have to be
documented, to reduce any adverse affect on performance.
#. Monasca Ceilometer publisher runs within Ceilometer Notification Agent component and invoked as a
last step in its data processing pipeline. It is an additional component that will have to to be
deployed on all the controller nodes. We will have to evaluate the performance impact of
Ceilometer Notification Agent when publishing events to Monasca Events API.
Other deployer impact
---------------------
#. The proposed new Monasca-Ceilometer events publisher will introduce
few new configuration options like
* events api endpoint
* events batch interval
* events batch size
* events retry interval
#. Monasca Ceilometer Events publisher will have to to be added to Ceilometer's
"[ceilometer.event.publisher]" section entry_points.txt
For example:
[ceilometer.event.publisher]
monasca = ceilometer.publisher.monclient:MonascaEventsPublisher
#. As part of developing new Monasca Ceilometer Events publisher devstack plugin would be updated to
add the above configuration changes.
Developer impact
----------------
#. The proposed change to Monasca Event Format will have an impact on existing Monasca Event API,
since Monasca Event Format will have to be tweaked. (See REST API Impact section above)
Implementation
==============
Assignee(s)
-----------
Primary assignee:
joadavis, aagate
Other contributors:
<launchpad-id or None>
Work Items
----------
#. Implement new Monasca Ceilometer Events publisher.
#. Implement monasca-ceilometer devstack plugin changes to deploy
new events publisher.
#. Implement unit tests for Events publisher.
#. Implement change to Monasca Event format in Monasca Events API.
Dependencies
============
#. Monasca Events API 1.0: https://storyboard.openstack.org/#!/story/2001654
#. Monasca Ceilometer project: https://github.com/openstack/monasca-ceilometer
#. Ceilometer Data processing and pipelines:
https://docs.openstack.org/ceilometer/pike/admin/telemetry-data-pipelines.html
Testing
=======
#. New Monasca Ceilometer Event publisher unit tests will be added, which can test publishing with
various config options events batch size, events batch interval, handling retry when Monasca
Event API is not available.
#. Adding tempest tests for Monasca Ceilometer events publisher could be looked at as part of
separate effort.
Please note that current Monasca Ceilometer samples publisher does not have tempest tests either
so having tempest tests for both events and samples publisher could be considered in the future.
Documentation Impact
====================
#. New Monasca Events Publisher config options will be documented
* events api endpoint
* events batch interval
* events batch size
* events retry interval
#. Recommended values for each of the config options will also be documented based on the size of
the cloud and resources for Cloud Operators.
References
==========
[1] Monasca Events API 1.0: https://storyboard.openstack.org/#!/story/2001654
[2] Monasca Ceilometer project: https://github.com/openstack/monasca-ceilometer
[3] Ceilometer Data processing and pipelines:
https://docs.openstack.org/ceilometer/pike/admin/telemetry-data-pipelines.html
[4] Ceilometer Events: https://docs.openstack.org/ceilometer/latest/admin/telemetry-events.html
[5] Openstack Panko: https://github.com/openstack/panko
[6] Monasca Event Format:
https://github.com/openstack/monasca-events-api/blob/master/doc/api-samples/v1/req_simple_event.json
[7] Ceilometer System Architecture Diagram:
https://docs.openstack.org/ceilometer/ocata/architecture.html
[8] Monasca Events POST v1.0 API:
https://github.com/openstack/monasca-events-api/blob/master/api-ref/source/events.inc
[9] Cross-Tenant Metric Submission:
https://github.com/openstack/monasca-agent/blob/master/docs/MonascaMetrics.md#cross-tenant-metric-submission
[10] Ceilometer pipeline yaml documentation:
https://docs.openstack.org/ceilometer/latest/admin/telemetry-data-pipelines.html
[11] No future for Panko or Aodh:
https://julien.danjou.info/lessons-from-openstack-telemetry-deflation/
[12] Ceilometer Events deprecated means Panko also deprecated:
http://eavesdrop.openstack.org/irclogs/%23openstack-telemetry/%23openstack-telemetry.2018-10-10.log.html
[13] Ceilometer Events marked as deprecated in Stein:
https://review.openstack.org/#/c/603336/

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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
=======================
Monasca Events Listener
=======================
https://storyboard.openstack.org/#!/story/2003023
Monasca Events API [1]_ was developed to store event data in Elasticsearch.
A new application could use the Monasca Events API to post an event directly for processing
and storage.
However, a general collection service is needed to capture the existing OpenStack Notifications
already generated by OpenStack Services and pass them to Monasca for storage and processing.
This specification proposes creating a new Monasca Events Listener to capture events and pass
them to Monasca services.
Problem description
===================
All Openstack services generate a lot of notifications or events which contain large amounts of
operational and state information about the service and its resources. Services such as Nova [14]_
already publish to a RabbitMQ topic.
This notification data is not currently available in Monasca.
Ceilometer data processing pipeline [3]_ provides an extensible mechanism of publishing samples and
events using a custom publisher. Ceilometer samples represent a quantity that can be measured
(e.g. the size of a volume) and events represent an occurrence of an event and do not have any
associated quantity (e.g. volume was created). The Telemetry project also has the Panko [5]_
service for indexing and storing these events.
A previous `spec <../../rocky/not-implemented/monasca-events-publishing.html>`_ was created to
specify an enhancement to Ceilometer to allow collected events to be published to the Monasca
Events API.
However, with the recent deprecation of Ceilometer's Event functionality [13]_, this is no longer
a long-term option.
This spec is for creating a new Monasca service which would listen for OpenStack Event messages
(often called notifications) and process them through Monasca by consuming the RabbitMQ message
and producing a post to the Monasca Events API with that event.
This service could use Ceilometer, Vitrage, Watcher, or another service as an example of how to
listen to notifications from OpenStack services such as Nova [14]_.
It is being proposed to make the Monasca Events Listener service a part of the Monasca Agent
code base and reuse code, including the existing monasca_setup script and config.
Use Cases
---------
#. Openstack notification data would be stored in Elasticsearch via the Monasca services
Example sequence:
#. Nova completes the creation of a VM
#. Nova generates a Notification message to oslo.messaging
#. oslo.messaging posts the message to RabbitMQ
#. Monasca Event Listener receives the Notification message from RabbitMQ
#. Monasca Event Listener validates and translates the Notification to a Monasca Events
API format according to the configuration
#. Monasca Event Listener publishes formatted Notification to Monasca Events API
#. Monasca Events API receives and validates formatted Notification
#. Monasca Events API stores event Notification in configured Elasticsearch instance
Proposed change
===============
#. Monasca Event Listener will be a new service which can be run in a Highly
Available configuration by running an instance of Monasca Event Listener
on each Controller node in a cloud. Each node will listen to OpenStack
notifications in RabbitMQ and convert notifications to a post to the Monasca
Events API. The Monasca Events API then passes the notification on as Kafka
messages on the 'monevents' topic, where the Monasca Persister will receive
and store them. By the nature of RabbitMQ clients, the load will be
distributed between the Monasca Events Listener instances (only one listener
will process each RabbitMQ message).
#. Monasca Event Listener will filter messages from OpenStack services based on
specification of event_types to be collected. This will reduce 'noise' and
focus event collection on those events that are deemed valuable.
This filtering specification can be from a configuration file, or optionally
could be controlled through a new API implemented as part of the Monasca
Events API service.
#. OpenStack Notifications consist of envelope and payload fields. See [15]_ and [16]_ for
examples.
Example OpenStack Notification data format:
.. code-block:: javascript
{
"_context_auth_token": "42630b3ea13242fcad20e0a92d0207f1",
"_context_domain": null,
"_context_instance_lock_checked": false,
"_context_is_admin": true,
"_context_project_domain": null,
"_context_project_id": "a4f77",
"_context_project_name": "admin",
"_context_quota_class": null,
"_context_read_deleted": "no",
"_context_read_only": false,
"_context_remote_address": "192.168.245.4",
"_context_request_id": "req-5948338c-f223-4fd8-9249-8769f7a3e460",
"_context_resource_uuid": null,
"_context_roles": [
"monasca-user",
"admin",
"KeystoneAdmin"
],
"_context_service_catalog": [
{
"endpoints": [
{
"adminURL": "http://192.168.245.8:8776/v2/a4f77",
"internalURL": "http://192.168.245.8:8776/v2/a4f77",
"publicURL": "http://192.168.245.9:8776/v2/a4f77",
"region": "region1"
}
],
"name": "cinderv2",
"type": "volumev2"
},
{
"endpoints": [
{
"adminURL": "http://192.168.245.8:8776/v1/a4f77",
"internalURL": "http://192.168.245.8:8776/v1/a4f77",
"publicURL": "http://192.168.245.9:8776/v1/a4f77",
"region": "region1"
}
],
"name": "cinder",
"type": "volume"
}
],
"_context_show_deleted": false,
"_context_tenant": "a4f77",
"_context_timestamp": "2015-09-18T20:54:23.468522",
"_context_user": "be396488c7034811a200a3cb1d103a28",
"_context_user_domain": null,
"_context_user_id": "be396488c7034811a200a3cb1d103a28",
"_context_user_identity": "be396488c7034811a200a3cb1d103a28 a4f77 - - -",
"_context_user_name": "admin",
"_unique_id": "ff9699d587bf4283a3c367ab88be1541",
"event_type": "compute.instance.create.start",
"message_id": "c6149ba1-34b3-4367-b8c2-b1d6f073742d",
"payload": {
"access_ip_v4": null,
"access_ip_v6": null,
"architecture": null,
"availability_zone": null,
"cell_name": "",
"created_at": "2015-09-18 20:55:25+00:00",
"deleted_at": "",
"disk_gb": 1,
"display_name": "testeee",
"ephemeral_gb": 0,
"host": null,
"hostname": "testeee",
"image_meta": {
"base_image_ref": "df0c8",
"container_format": "bare",
"disk_format": "qcow2",
"min_disk": "1",
"min_ram": "0"
},
"image_name": "glanceaaa3",
"image_ref_url": "http://192.168.245.5:9292/images/df0c8",
"instance_flavor_id": "1",
"instance_id": "abd2ef5c-0381-434a-8efc-d7b39b28a2b6",
"instance_type": "m1.tiny",
"instance_type_id": 4,
"kernel_id": "",
"launched_at": "",
"memory_mb": 512,
"metadata": {},
"node": null,
"os_type": null,
"progress": "",
"ramdisk_id": "",
"reservation_id": "r-1ghilddw",
"root_gb": 1,
"state": "building",
"state_description": "",
"tenant_id": "a4f77",
"terminated_at": "",
"user_id": "be396488c7034811a200a3cb1d103a28",
"vcpus": 1
},
"priority": "INFO",
"publisher_id": "compute.ccp-compute0001-mgmt",
"timestamp": "2015-09-18 20:55:37.639023"
}
#. All the fields with the prefix of '_context' are the envelope fields, the
other interesting fields are
#. 'message_id' - notification identifier
#. 'payload' - contains most of the relevant and useful information in JSON format
#. 'priority' - notification priority
#. 'publisher_id' - notification publisher
#. 'timestamp' - notification timestamp
#. Monasca Event Listener converts the OpenStack notifications to Monasca events format.
This format will be suitable for Kafka messaging and will match the expected data fields
of the Monasca Persister. This conversion and validation should be common between the
Monasca Event Listener and Monasca Event API.
#. The Kafka client connection will handle communication issues such as reconnections and
resending as needed.
#. Monasca Events API allows a field called 'payload' which can be in an arbitrary
nested JSON format.
TODO: mappings
Example Monasca Event Format:
.. code-block:: javascript
events: [
{
dimensions": {
"service": "compute.ccp-compute0001-mgmt",
"topic": "notification.sample",
"hostname": "nova-compute:compute
},
event: {
"event_type": "compute.instance.create.start",
"payload": {
"access_ip_v4": null,
"access_ip_v6": null,
"architecture": null,
"availability_zone": null,
"cell_name": "",
"created_at": "2015-09-18 20:55:25+00:00",
"deleted_at": "",
"disk_gb": 1,
"display_name": "testeee",
"ephemeral_gb": 0,
"host": null,
"hostname": "testeee",
"image_meta": {
"base_image_ref": "df0c8",
"container_format": "bare",
"disk_format": "qcow2",
"min_disk": "1",
"min_ram": "0"
},
"image_name": "glanceaaa3",
"image_ref_url": "http://192.168.245.5:9292/images/df0c8",
"instance_flavor_id": "1",
"instance_id": "abd2ef5c-0381-434a-8efc-d7b39b28a2b6",
"instance_type": "m1.tiny",
"instance_type_id": 4,
"kernel_id": "",
"launched_at": "",
"memory_mb": 512,
"metadata": {},
"node": null,
"os_type": null,
"progress": "",
"ramdisk_id": "",
"reservation_id": "r-1ghilddw",
"root_gb": 1,
"state": "building",
"state_description": "",
"tenant_id": "a4f77",
"terminated_at": "",
"user_id": "be396488c7034811a200a3cb1d103a28",
"vcpus": 1
}
},
publisher_id: "compute.ccp-compute0001-mgmt",
priority: "INFO"
}
]
#. Following fields in Monasca Event data may not be available in the OpenStack notification
data format:
* "service"
* "dimensions.topic"
* "event.priority"
We are proposing removing these fields from Monasca Event format (will be done as a separate
spec/implementation process) for the following reasons:
"service": Currently OpenStack notifications do not specify a service, that
generated the notification in a consistent way. It might be possible to create an external
mapping file which maps event name to a service but its hard to maintain such mapping over a
period of time.
"dimensions.topic": This field is not available in the source OpenStack notification.
However, the Monasca Event Listener may be able to save the RabbitMQ topic that the notification
was collected from. In that case, this field should be used.
"event.priority": This field is not currently available in Ceilometer Event format. It is
available in the source OpenStack notification. Note: If we think this field can be useful we can
propose adding it to the Monasca Event Listener format.
#. Following new fields will be added to Monasca Event data as dimensions:
* "dimensions.publisher_id": Identifier for the publisher that generated the event.
* "dimensions.user_id": Identifier for user that generated the event.
* "dimensions.project_id": Identifier of the project that generated the event.
#. 'hostname' is available in the event payload, but its location might differ from event to event.
#. The proposed new Monasca Event Listener will have the ability to submit event
data in a batch and at a configurable frequency (similar to current samples publisher). The
event data will be published if the items in the current batch reach their maximum size
(config setting) or if certain time interval has elapsed since the last publish
(config setting). This will make sure that the batch does not get huge at the same time
there is no significant delay in publishing of the events to Monasca Events API.
#. Monasca Event Listener will have a configuration file to configure connection information for
both RabbitMQ and Monasca Events API.
#. The "tenant_id" and "user_id" that the notification relates to are available in "payload"
section of the notification, and these notifications are generated by each service itself.
There is no additional "OpenStack-operator-agent" like component or functionality required to
fetch that data from the service and publish to monasca event api on behalf of the original
tenant.
(Ceilometer publishing pipeline simply extracts these "tenant_id" and "user_id" fields from the
"payload" and makes those fields available as "tenant_id" and "user_id" traits, which would then
be mapped to "dimensions.project_id" and "dimensions.user_id" fields in monasca events format.)
In other words, original "tenant_id" and "user_id" values are available in
the payload of the notification, and will make its way to "dimensions.tenant_id"
and "dimensions.user_id" in Monasca Event.
Questions/TODO:
* Q: Do we need to do anything special to handle multi-tenancy in monasca-events api like being
done for metrics [9]_ ? Would original user_id and tenant_id in "dimensions.user_id" and
"dimensions.tenant_id" fields in dimensions serve this purpose?
* A: Monasca Events Listener can start with sending all events to a single "admin" tenant
and if required in the future some other process could copy select metrics back to tenant
projects.
* Q: In Ceilometer V2 API (which has been deprecated and removed), when querying data the role
"admin" could access data for all tenants, whereas a user with "ceilometer-admin" role could
access only data for a particular tenant. Can we implement something like this for
monasca-events api when querying for data?
* A: In Monasca API every request is scoped to the project, so there is no equivalent of
Ceilometer's "admin" role to query data for all projects. So placing all events in to
an "admin" project may be the best approach.
* Q: How should services which generate notifications but do not include a tenant_id be
handled? For example Keystone [16]_.
How does Ceilometer handle such events?
* A: If all events are in an "admin" project then admin metrics like shared ceph cluster
load or provider network load can be copied back to tenants so they may understand how
infrastructure is affecting their workload.
* Note: Configuration of Elasticsearch cluster is out of scope for this spec. If needed
could assign a separate Elasticsearch cluster to the events API to avoid overloads.
Alternative Solutions
---------------------
#. Reuse the Ceilometer functionality to collect and publish events to the
Monasca Events API. While this may be less work initially, Ceilometer has
deprecated the Events functionality as of Stein. [13]_
#. An alternate Events Listener was proposed that would listen for RabbitMQ events
then publish them directly to the 'monevents' topic in Kafka. Discussion on this
can be seen in the git history for this document and in IRC logs [18]_.
Pro:
* A much simpler approach, more efficient that HTTP hop through another service.
* No need for batching in service, as RabbitMQ and Kafka clients would handle fast
throughput and short network interruptions.
Con:
* Nova Cells v2 each have their own RabbitMQ instances. While most deployments
would likely have a centralized RabbitMQ, it is not required in the documented
architecture.
* Regions may also cause separation of RabbitMQ instances that need to be monitored.
* While it might be possible to have a service/agent in each Cell publish back to
a centralized to Kafka directly, our authentication and networking for Kafka was
not designed to support that.
#. OpenStack Panko [5]_ is a event storage and REST API for Ceilometer and could
be used instead of a Monasca solution.
Pro:
* An 'official' subproject within Telemetry, so there is some community recognition.
Con:
* Its primary storage is in a relational database which has problems with scale.
* It is not maintained actively and not ready for production. [11]_
* It will be deprecated eventually. [12]_
Data model impact
-----------------
None
REST API impact
---------------
#. We are proposing to tweak the Monasca Event data format by removing and adding following
fields as mentioned in "Proposed change" section above.
Remove fields or make them optional (JSON path notation): "service", "dimensions.topic",
"dimensions.hostname" and "event.priority"
Add fields (JSON path notation): "dimensions.publisher_id", "dimensions.user_id" and
"dimensions.project_id"
This change will have an impact on Monasca Events API.
Security impact
---------------
The proposed Monasca Event Listener will collect and publish OpenStack event
(notification) data to Monasca Events API. OpenStack notification data does not
have any sensitive data like 'tokens'.
Notifications do contain 'user_id' and 'project_id' fields but do not
contain any Personally Identifiable Information (PII) for the user or
the project.
Other end user impact
---------------------
None.
Performance Impact
------------------
#. The number of notifications(events) generated by different services will depend on the capacity
of the cloud along with the number of resources being created by the users.
For example, if there was a large number of compute VM's being created or destroyed it could
lead to a surge in number of notifications (events) that would have to be published. Optimum
configuration options related to say event batch size and event batch interval would have to be
documented, to reduce any adverse affect on performance.
#. The proposed Monasca Event Listener is a new service, so performance is unknown. However, the
Monasca API has been shown to have a high performance throughput.
Other deployer impact
---------------------
#. The proposed Monasca Event Listener will introduce a
few new configuration options like
* RabbitMQ connection information
* Monasca Events API endpoint URL
* events batch interval
* events batch size
* events retry interval
* Keystone credentials for obtaining a token
* Conversion options for OpenStack notifications to the Monasca Event format. This may
be stored in separate pipeline configuration files, similar to how transform specs
are configured in Monasca Transform.
#. As part of developing new Monasca Event Listener devstack plugin would be
updated to add the above configuration changes.
Developer impact
----------------
#. The proposed change to Monasca Event Format will have an impact on existing Monasca Event API,
since Monasca Event Format will have to be tweaked. (See REST API Impact section above)
Implementation
==============
Assignee(s)
-----------
Primary assignee:
joadavis, aagate
Other contributors:
<launchpad-id or None>
Work Items
----------
#. Implement new Monasca Event Listener.
* Connection to RabbitMQ for OpenStack Notifications
* Add filtering of notifications for configured event_types
* Specification in configuration file
* (Optional) Creation of a new API to configure event_type subscriptions
* Validation of OpenStack Notification data and format
* Conversion of data format to meet Monasca Events requirements
* Publishing to Monasca Events API
* Configuration of conversion specifications per-event type
#. Implement monasca devstack plugin changes to deploy
new Events Listener service.
#. Implement unit tests for Monasca Event Listener.
Dependencies
============
None
Testing
=======
#. New Monasca Event Listener unit tests will be added, which can test publishing with
various config options events batch size, events batch interval, handling retry when Monasca
Event API is not available.
#. Adding tempest tests for Monasca Event Listener could be looked at as part of
separate effort.
Documentation Impact
====================
#. New Monasca Event Listener config options will be documented
#. Recommended values for each of the config options will also be documented based on the size of
the cloud and resources for Cloud Operators.
References
==========
.. [1] Monasca Events API 1.0: https://git.openstack.org/cgit/openstack/monasca-events-api/
[2] Monasca Ceilometer project: https://github.com/openstack/monasca-ceilometer
.. [3] Ceilometer Data processing and pipelines: https://docs.openstack.org/ceilometer/pike/admin/telemetry-data-pipelines.html
[4] Ceilometer Events: https://docs.openstack.org/ceilometer/latest/admin/telemetry-events.html
.. [5] Openstack Panko: https://github.com/openstack/panko
[6] Monasca Event Format: https://github.com/openstack/monasca-events-api/blob/master/doc/api-samples/v1/req_simple_event.json
[7] Ceilometer System Architecture Diagram: https://docs.openstack.org/ceilometer/ocata/architecture.html
[8] Monasca Events POST v1.0 API: https://github.com/openstack/monasca-events-api/blob/master/api-ref/source/events.inc
.. [9] Cross-Tenant Metric Submission: https://github.com/openstack/monasca-agent/blob/master/docs/MonascaMetrics.md#cross-tenant-metric-submission
[10] Ceilometer pipeline yaml documentation: https://docs.openstack.org/ceilometer/latest/admin/telemetry-data-pipelines.html
.. [11] No future for Panko or Aodh: https://julien.danjou.info/lessons-from-openstack-telemetry-deflation/
.. [12] Ceilometer Events deprecated means Panko also deprecated: http://eavesdrop.openstack.org/irclogs/%23openstack-telemetry/%23openstack-telemetry.2018-10-10.log.html
.. [13] Ceilometer Events marked as deprecated in Stein: https://review.openstack.org/#/c/603336/
.. [14] Nova notification version update lists services effected (see "Deprecating legacy notifications"): https://etherpad.openstack.org/p/nova-ptg-stein
.. [15] Nova notification reference: https://docs.openstack.org/nova/latest/reference/notifications.html#existing-versioned-notifications
.. [16] Keystone notification reference: https://docs.openstack.org/keystone/latest/advanced-topics/event_notifications.html#example-notification-project-create
[17] Monasca Events API publisher to Kafka: https://github.com/openstack/monasca-events-api/blob/master/monasca_events_api/app/common/events_publisher.py
.. [18] Monasca IRC meeting Dec 15, 2018: http://eavesdrop.openstack.org/meetings/monasca/2018/monasca.2018-12-12-15.00.log.html