An Event is a record generated during engine execution. Such an event captures what has happened inside the senlin-engine. The senlin-engine service generates event records when it is performing some actions or checking policies.
An event has a level
property which can be interpreted as the severity
level value of the event:
DEBUG
level. Events at this level can be ignored
safely by users. For developers they may provide some useful information for
debugging the code.INFO
level. Events at this level are mostly about
notifying that some operations have been successfully performed.WARNING
level. Events at this level are used to
signal some unhealthy status or anomalies detected by the engine. These
events should be monitored and checked when operating a cluster.ERROR
level. Events at this level signifies some
failures in engine operations. These event should be monitored and checked
when operating a cluster. Usually some user intervention is expected to
recover a cluster from this status.CRITICAL
level. Events at this level are about
serious problems encountered by the engine. The engine service may have
run into some bugs. User intervention is required to do a recovery.Senlin provides an open architecture for event dispatching. Two of the
built-in dispatchers are database
and message
.
1. The database
dispatcher dumps the events into database tables and it
is enabled by default.
2. The message
dispatcher converts the event objects into versioned event
notifications and published on the global message queue. This dispatcher is
by default disabled. To enable it, you can add the following line to the
[DEFAULT]
section of the senlin.conf
file and then restart the service
engine:
[default]
event_dispatchers = message
Based on your deployment settings, you have to add the following lines to
the senlin.conf
file as well when using message
dispatcher. This lines
set messaging
as the default driver used by the oslo.messaging
package:
[oslo_messaging_notifications]
driver = messaging
With this configuration, the database dispatcher will be disabled, which means you can only access to the events by the message queue.
3. The event_dispatchers
field is MultiString
, you can enable
both the database
and message
dispatchers if needed by the following
configuration:
[default]
event_dispatchers = database
event_dispatchers = message
[oslo_messaging_notifications]
driver = messaging
Note that unprocessed event notifications which are not associated with a
TTL (time to live) value by default will remain queued at the message bus,
please make sure the Senlin event notifications will be subscribed and
processed by some services before enabling the message
dispatcher.
By default, we use the senlin
exchange which type is TOPIC
to route
the notifications to queues with different routing_key
. The queues name
could be versioned_notifications.debug
, versioned_notifications.info
,
versioned_notifications.warn
and versioned_notifications.error
that
depends on the log level you are using in senlin.conf
. The corresponding
routing_key
are the same as the queues’ name.
There are two options to consume the notifications:
senlin
exchange with
corresponding routing_key
to customize the flow.Since the event dispatchers are designed as plug-ins, you can develop your own event dispatchers and have senlin engine load them on startup. For more details on developing and plugging in your own event dispatchers, please refer to the Plugin Writer’s Guide document.
The following sections are about examining events when using the database
dispatcher which creates database records when events happen.
The following command lists the events by the Senlin engine:
$ openstack cluster event list
+----------+---------------------+---------------+----------+--------------+-----------------------+-----------+-------+------------+
| id | generated_at | obj_type | obj_id | obj_name | action | status | level | cluster_id |
+----------+---------------------+---------------+----------+--------------+-----------------------+-----------+-------+------------+
| 1f72eb5e | 2015-12-17T15:41:48 | NODE | 427e64f3 | node-7171... | update | ACTIVE | 20 | |
| 20b8eb9a | 2015-12-17T15:41:49 | NODE | 6da22a49 | node-7171... | update | ACTIVE | 20 | |
| 23721815 | 2015-12-17T15:42:51 | NODEACTION | 5e9a9d3d | node_dele... | NODE_DELETE | START | 20 | |
| 54f9eae4 | 2015-12-17T15:41:36 | CLUSTERACTION | 1bffa11d | cluster_c... | CLUSTER_CREATE | SUCCEEDED | 20 | 9f1883a7 |
| 7e30df62 | 2015-12-17T15:42:51 | CLUSTERACTION | d3cef701 | cluster_d... | CLUSTER_DELETE | START | 20 | 9f1883a7 |
| bf51f23c | 2015-12-17T15:41:54 | CLUSTERACTION | d4dbbcea | cluster_s... | CLUSTER_SCALE_OUT | START | 20 | 9f1883a7 |
| c58063e9 | 2015-12-17T15:42:51 | NODEACTION | b2292bb1 | node_dele... | NODE_DELETE | START | 20 | |
| ca7d30c6 | 2015-12-17T15:41:38 | CLUSTERACTION | 0be70b0f | attach_po... | CLUSTER_ATTACH_POLICY | START | 20 | 9f1883a7 |
| cfe5d0d7 | 2015-12-17T15:42:51 | CLUSTERACTION | 42cf5baa | cluster_d... | CLUSTER_DELETE | START | 20 | 9f1883a7 |
| fe2fc810 | 2015-12-17T15:41:49 | CLUSTERACTION | 0be70b0f | attach_po... | CLUSTER_ATTACH_POLICY | SUCCEEDED | 20 | 9f1883a7 |
+----------+---------------------+---------------+----------+--------------+-----------------------+-----------+-------+------------+
The openstack cluster event list command line supports various options when listing the events.
You can specify the sorting keys and sorting direction when list events,
using the option --sort
. The --sort
option accepts a
string of format key1[:dir1],key2[:dir2],key3[:dir3]
, where the keys used
are event properties and the dirs can be one of asc
and desc
. When
omitted, Senlin sorts a given key using asc
as the default direction.
For example, the following command sorts the events using the timestamp
property in descending order:
$ openstack cluster event list --sort timestamp:desc
When sorting the list of events, you can use one of timestamp
, level
,
otype
, oname
, user
, action
and status
.
You can filter the list of events using the --filters`
. For example,
the following command filters the event list by the otype
property:
$ openstack cluster event list --filters otype=NODE
The option --filters
accepts a list of key-value pairs separated by
semicolon (;
), where each pair is expected to be of format key=val
.
The valid keys for filtering include oname
, otype
, oid
,
cluster_id
, action
, level
or any combination of them.
In case you have a huge collection of events (which is highly likely the case),
you can limit the number of events returned using the option
--limit
. For example:
$ openstack cluster event list --limit 10
Another option you can specify is the ID of an event after which you want to
see the returned list starts. In other words, you don’t want to see those
events with IDs that is or come before the one you specify. You can use the
option --marker
for this purpose. For example:
$ openstack cluster event list --limit 20 \
--marker 2959122e-11c7-4e82-b12f-f49dc5dac270
At most 20 action records will be returned in this example and its UUID comes after the one specified from the command line.
You can use the senlin command line to show the details about an event you are interested in. When specifying the identity of the event, you can use its name, its ID or its “short ID” . Senlin API and engine will verify if the identifier you specified can uniquely identify an event. An error message will be returned if there is no event matching the identifier or if more than one event matching it.
An example is shown below:
$ openstack cluster event show 19ba155a
+---------------+--------------------------------------+
| Field | Value |
+---------------+--------------------------------------+
| action | NODE_DELETE |
| cluster_id | ce85d842-aa2a-4d83-965c-2cab5133aedc |
| generated_at | 2015-12-17T15:43:26+00:00 |
| id | 19ba155a-d327-490f-aa0f-589f67194b2c |
| level | INFO |
| location | None |
| name | None |
| obj_id | cd9f519a-5589-4cbf-8a74-03b12fd9436c |
| obj_name | node-ce85d842-003 |
| obj_type | NODE |
| project_id | 42d9e9663331431f97b75e25136307ff |
| status | end |
| status_reason | Node deleted successfully. |
| user_id | 5e5bf8027826429c96af157f68dc9072 |
+---------------+--------------------------------------+
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