1 .. This work is licensed under a Creative Commons Attribution 4.0 International License.
2 .. http://creativecommons.org/licenses/by/4.0
3 .. (c) OPNFV, Intel Corporation and others.
4 .. _barometer-ves-userguide:
6 ==========================
7 VES Application User Guide
8 ==========================
10 The Barometer repository contains a python based application for VES (VNF Event
11 Stream) which receives the `collectd`_ specific metrics via `Kafka`_ bus,
12 normalizes the metric data into the VES message format and sends it into the VES
15 The application currently supports pushing platform relevant metrics through the
16 additional measurements field for VES.
18 Collectd has a ``write_kafka`` plugin that sends collectd metrics and values to
19 a Kafka Broker. The VES message formatting application, ves_app.py, receives metrics from
20 the Kafka broker, normalises the data to VES message format for forwarding to VES collector.
21 The VES message formatting application will be simply referred to as the "VES application"
24 The VES application can be run in host mode (baremetal), hypervisor mode (on a host with a hypervisor
25 and VMs running) or guest mode(within a VM). The main software blocks that are required to run the
26 VES application demo are:
36 1. Dependencies: install JAVA & Zookeeper.
42 $ sudo apt-get install default-jre
43 $ sudo apt-get install zookeeperd
44 $ sudo apt-get install python-pip
51 $ sudo yum install java-1.8.0-openjdk
52 $ sudo yum install epel-release
53 $ sudo yum install python-pip
54 $ sudo yum install zookeeper
55 $ sudo yum install telnet
56 $ sudo yum install wget
58 .. note:: You may need to add the repository that contains zookeeper.
59 To do so, follow the step below and try to install `zookeeper` again
60 using steps above. Otherwise, skip next step.
65 https://archive.cloudera.com/cdh5/one-click-install/redhat/7/x86_64/cloudera-cdh-5-0.x86_64.rpm
71 $ sudo zookeeper-server start
73 if you get the error message like ``ZooKeeper data directory is missing at /var/lib/zookeeper``
74 during the start of zookeeper, initialize zookeeper data directory using
75 the command below and start zookeeper again, otherwise skip the next step.
79 $ sudo /usr/lib/zookeeper/bin/zkServer-initialize.sh
80 No myid provided, be sure to specify it in /var/lib/zookeeper/myid if using non-standalone
82 2. Test if Zookeeper is running as a daemon.
86 $ telnet localhost 2181
88 Type 'ruok' & hit enter.
89 Expected response is 'imok' which means that Zookeeper is up running.
93 .. note:: VES doesn't work with version 0.9.4 of kafka-python. The
94 recommended/tested version is 1.3.3.
98 $ sudo pip install kafka-python
99 $ wget "https://archive.apache.org/dist/kafka/1.0.0/kafka_2.11-1.0.0.tgz"
100 $ tar -xvzf kafka_2.11-1.0.0.tgz
101 $ sed -i -- 's/#delete.topic.enable=true/delete.topic.enable=true/' kafka_2.11-1.0.0/config/server.properties
102 $ sudo nohup kafka_2.11-1.0.0/bin/kafka-server-start.sh \
103 kafka_2.11-1.0.0/config/server.properties > kafka_2.11-1.0.0/kafka.log 2>&1 &
105 .. note:: If Kafka server fails to start, please check if the platform IP
106 address is associated with the hostname in the static host lookup
107 table. If it doesn't exist, use the following command to add it.
111 $ echo "$(ip route get 8.8.8.8 | awk '{print $NF; exit}') $HOSTNAME" | sudo tee -a /etc/hosts
113 4. Test the Kafka Installation
115 To test if the installation worked correctly there are two scripts, producer and consumer scripts.
116 These will allow you to see messages pushed to broker and receive from broker.
118 Producer (Publish "Hello World"):
122 $ echo "Hello, World" | kafka_2.11-1.0.0/bin/kafka-console-producer.sh \
123 --broker-list localhost:9092 --topic TopicTest > /dev/null
125 Consumer (Receive "Hello World"):
129 $ kafka_2.11-1.0.0/bin/kafka-console-consumer.sh --zookeeper \
130 localhost:2181 --topic TopicTest --from-beginning --max-messages 1 --timeout-ms 3000
136 Install development tools:
142 $ sudo apt-get install build-essential bison autotools-dev autoconf
143 $ sudo apt-get install pkg-config flex libtool
149 $ sudo yum group install 'Development Tools'
151 .. The libkafka installed via the package manager may not work with collectd
152 (due to compilation issue). Thus, it's recommented to use the library installed
153 from sources using latest stable version of libkafka.
155 Install Apache Kafka C/C++ client library:
159 $ git clone https://github.com/edenhill/librdkafka.git ~/librdkafka
161 $ git checkout -b v0.9.5 v0.9.5
162 $ ./configure --prefix=/usr
166 Build collectd with Kafka support:
170 $ git clone https://github.com/collectd/collectd.git ~/collectd
173 $ ./configure --with-librdkafka=/usr --without-perl-bindings --enable-perl=no
174 $ make && sudo make install
178 If installing from git repository ``collectd.conf`` configuration file will be located in
179 directory ``/opt/collectd/etc/``. If installing from via a package manager ``collectd.conf``
180 configuration file will be located in directory ``/etc/collectd/``
182 Configure and start collectd. Modify Collectd configuration file ``collectd.conf``
185 - Within a VM: `Setup VES application (guest mode)`_
186 - On Host with VMs: `Setup VES application (hypervisor mode)`_
187 - No Virtualization: `Setup VES application (host mode)`_
189 Start collectd process as a service as described in :ref:`install-collectd-as-a-service`.
191 Setup VES application (guest mode)
192 ----------------------------------
194 In this mode Collectd runs from within a VM and sends metrics to the VES collector.
196 .. figure:: ves-app-guest-mode.png
200 Install dependencies:
204 $ sudo pip install pyyaml python-kafka
206 Clone Barometer repo and start the VES application:
210 $ git clone https://gerrit.opnfv.org/gerrit/barometer
211 $ cd barometer/3rd_party/collectd-ves-app/ves_app
212 $ nohup python ves_app.py --events-schema=guest.yaml --config=ves_app_config.conf > ves_app.stdout.log &
215 Modify Collectd configuration file ``collectd.conf`` as following:
217 .. include:: collectd-ves-guest.conf
221 Start collectd process as a service as described in :ref:`install-collectd-as-a-service`.
225 The above configuration is used for a localhost. The VES application can be
226 configured to use remote VES collector and remote Kafka server. To do
227 so, the IP addresses/host names needs to be changed in ``collector.conf``
228 and ``ves_app_config.conf`` files accordingly.
231 Setup VES application (hypervisor mode)
232 ----------------------------------------
234 This mode is used to collect hypervisor statistics about guest VMs and to send
235 those metrics into the VES collector. Also, this mode collects host statistics
236 and send them as part of the guest VES message.
238 .. figure:: ves-app-hypervisor-mode.png
240 VES hypervisor mode setup
242 Running the VES in hypervisor mode looks like steps described in
243 `Setup VES application (guest mode)`_ but with the following exceptions:
245 - The ``hypervisor.yaml`` configuration file should be used instead of ``guest.yaml``
246 file when VES application is running.
248 - Collectd should be running on hypervisor machine only.
250 - Addition ``libvirtd`` dependencies needs to be installed on where
251 collectd daemon is running. To install those dependencies, see :ref:`virt-plugin`
252 section of Barometer user guide.
254 - The next (minimum) configuration needs to be provided to collectd to be able
255 to generate the VES message to VES collector.
258 At least one VM instance should be up and running by hypervisor on the host.
260 .. include:: collectd-ves-hypervisor.conf
264 Start collectd process as a service as described in :ref:`install-collectd-as-a-service`.
268 The above configuration is used for a localhost. The VES application can be
269 configured to use remote VES collector and remote Kafka server. To do
270 so, the IP addresses/host names needs to be changed in ``collector.conf``
271 and ``ves_app_config.conf`` files accordingly.
274 .. note:: The list of the plugins can be extented depends on your needs.
277 Setup VES application (host mode)
278 ----------------------------------
280 This mode is used to collect platform wide metrics and to send those metrics into the VES collector.
281 It is most suitable for running within a baremetal platform.
283 Install dependencies:
287 $ sudo pip install pyyaml
289 Clone Barometer repo and start the VES application:
293 $ git clone https://gerrit.opnfv.org/gerrit/barometer
294 $ cd barometer/3rd_party/collectd-ves-app/ves_app
295 $ nohup python ves_app.py --events-schema=host.yaml --config=ves_app_config.conf > ves_app.stdout.log &
298 .. figure:: ves-app-host-mode.png
300 VES Native mode setup
302 Modify collectd configuration file ``collectd.conf`` as following:
304 .. include:: collectd-ves-host.conf
307 Start collectd process as a service as described in :ref:`install-collectd-as-a-service`.
311 The above configuration is used for a localhost. The VES application can be
312 configured to use remote VES collector and remote Kafka server. To do
313 so, the IP addresses/host names needs to be changed in ``collector.conf``
314 and ``ves_app_config.conf`` files accordingly.
317 .. note:: The list of the plugins can be extented depends on your needs.
321 Setup VES Test Collector
322 ------------------------
324 .. note:: Test Collector setup is required only for VES application testing
327 Install dependencies:
331 $ sudo pip install jsonschema
333 Clone VES Test Collector:
337 $ git clone https://github.com/att/evel-test-collector.git ~/evel-test-collector
339 Modify VES Test Collector config file to point to existing log directory and
344 $ sed -i.back 's/^\(log_file[ ]*=[ ]*\).*/\1collector.log/' ~/evel-test-collector/config/collector.conf
345 $ sed -i.back 's/^\(schema_file[ ]*=.*\)event_format_updated.json$/\1CommonEventFormat.json/' ~/evel-test-collector/config/collector.conf
347 Start VES Test Collector:
351 $ cd ~/evel-test-collector/code/collector
352 $ nohup python ./collector.py --config ../../config/collector.conf > collector.stdout.log &
355 VES application configuration description
356 -----------------------------------------
358 **Details of the Vendor Event Listener REST service**
360 REST resources are defined with respect to a ``ServerRoot``::
362 ServerRoot = https://{Domain}:{Port}/{optionalRoutingPath}
364 REST resources are of the form::
366 {ServerRoot}/eventListener/v{apiVersion}`
367 {ServerRoot}/eventListener/v{apiVersion}/{topicName}`
368 {ServerRoot}/eventListener/v{apiVersion}/eventBatch`
370 Within the VES directory (``3rd_party/collectd-ves-app/ves_app``) there is a
371 configuration file called ``ves_app_conf.conf``. The description of the
372 configuration options are described below:
375 VES domain name. It can be IP address or hostname of VES collector
376 (default: ``127.0.0.1``)
379 VES port (default: ``30000``)
382 Used as the "optionalRoutingPath" element in the REST path (default: ``vendor_event_listener``)
385 Used as the "topicName" element in the REST path (default: ``example_vnf``)
387 **UseHttps** *true|false*
388 Allow application to use HTTPS instead of HTTP (default: ``false``)
390 **Username** *"username"*
391 VES collector user name (default: empty)
393 **Password** *"passwd"*
394 VES collector password (default: empty)
396 **SendEventInterval** *interval*
397 This configuration option controls how often (sec) collectd data is sent to
398 Vendor Event Listener (default: ``20``)
400 **ApiVersion** *version*
401 Used as the "apiVersion" element in the REST path (default: ``3``)
404 Kafka Port (Default ``9092``)
406 **KafkaBroker** *host*
407 Kafka Broker domain name. It can be an IP address or hostname of local or remote server
408 (default: ``localhost``)
411 VES YAML configuration format
412 -----------------------------
414 The format of the VES message is generated by the VES application based on the
415 YAML schema configuration file provided by user via ``--events-schema``
416 command-line option of the application.
418 .. note:: Use ``--help`` option of VES application to see the
419 description of all available options
421 .. note:: The detailed installation guide of the VES application is described in
422 the `VES Application User Guide`_.
424 The message defined by YAML schema should correspond to format defined in
425 `VES shema definition`_.
427 .. warning:: This section doesn't explain the YAML language itself, so the
428 knowledge of the YAML language is required before continue reading it!
430 Since, the VES message output is a JSON format, it's recommended to understand
431 how YAML document is converted to JSON before starting to create a new YAML
432 definition for the VES. E.g.:
434 The following YAML document:
439 additionalMeasurements:
441 instance: someinstance
443 will be converted to JSON like this:
448 "additionalMeasurements": {
449 "instance": "someinstance",
454 .. note:: The `YAML syntax` section of `PyYAML documentation`_ can be used
455 as a reference for this.
461 The VES agent can generate two type of messages which are sent to the VES
462 collector. Each message type must be specified in the YAML configuration file
463 using a specific YAML tag.
466 This type is used to send a message defined in YAML configuration to the VES
467 collector with a specified interval (default is 20 sec and it's configurable
468 via command line option of the application). This type can be specified in
469 the configuration using ``!Measurements`` tag. For instance:
475 My Host Measurements: !Measurements
476 ... # message definition
479 This type is used to send a message defined in YAML configuration to the VES
480 collector when collectd notification is received from Kafka bus (collectd
481 ``write_kafka`` plugin). This type can be specified in the configuration
482 using ``!Events`` tag. For instance:
489 ... # event definition
492 Collectd metrics in VES
493 -----------------------
495 The VES application caches collectd metrics received via Kafka bus. The data
496 is stored in a table format. It's important to know it before mapping collectd
497 metric values to message defined in YAML configuration file.
499 VES collectd metric cache example:
501 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
502 | host | plugin | plugin_instance | type | type_instace | time | value | ds_name | interval |
503 +===========+===========+====================+===========+================+===================+========+=========+==========+
504 | localhost | cpu | | percent | user | 1509535512.30567 | 16 | value | 10 |
505 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
506 | localhost | memory | | memory | free | 1509535573.448014 | 798456 | value | 10 |
507 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
508 | localhost | interface | | eth0 | if_packets | 1509544183.956496 | 253 | rx | 10 |
509 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
510 | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | percent | virt_cpu_total | 1509544402.378035 | 0.2 | value | 10 |
511 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
512 | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | memory | rss | 1509544638.55119 | 123405 | value | 10 |
513 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
514 | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | if_octets | vnet1 | 1509544646.27108 | 67 | tx | 10 |
515 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
516 | cc659a52 | virt | Ubuntu-16.04 | percent | virt_cpu_total | 1509544745.617207 | 0.3 | value | 10 |
517 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
518 | cc659a52 | virt | Ubuntu-16.04 | memory | rss | 1509544754.329411 | 4567 | value | 10 |
519 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
520 | cc659a52 | virt | Ubuntu-16.04 | if_octets | vnet0 | 1509544760.720381 | 0 | rx | 10 |
521 +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+
523 It's possible from YAML configuration file to refer to any field of any row of
524 the table via special YAML tags like ``ValueItem`` or ``ArrayItem``. See the
525 `Collectd metric reference`_ reference for more details.
527 .. note:: The `collectd data types file`_ contains map of ``type`` to
528 ``ds_name`` field. It can be used to get possible value for ``ds_name``
529 field. See the `collectd data types description`_ for more details on
533 Aging of collectd metric
534 ~~~~~~~~~~~~~~~~~~~~~~~~
536 If the metric will not be updated by the collectd during the double metric
537 interval time, it will be removed (aged) from VES internal cache.
543 There are four type of references supported by the YAML format: System,
544 Config, Collectd metric and Collectd notification. The format of the reference
549 "{<ref type>.<attribute name>}"
551 .. note:: Possible values for ``<ref type>`` and ``<attribute name>`` are
552 described in farther sections.
558 This reference is used to get system statistics like time, date etc. The system
559 reference (``<ref type>`` = ``system``) can be used in any place of the YAML
560 configuration file. This type of reference provides the following attributes:
563 The name of the host where VES application is running.
566 Unique ID during VES application runtime.
569 Current time in seconds since the Epoch. For example ``1509641411.631951``.
572 Current date in ISO 8601 format, ``YYYY-MM-DD``. For instance ``2017-11-02``.
579 Date: "{system.date}"
585 This reference is used to get VES configuration described in `VES application
586 configuration description`_ sectoin. The reference (``<ref type>`` = ``config``)
587 can be used in any place of the YAML configuration file. This type of reference
588 provides the following attributes:
591 Measurements dispatch interval. It referenses to ``SendEventInterval``
592 configuration of the VES application.
599 Interval: "{config.interval}"
602 Collectd metric reference
603 ~~~~~~~~~~~~~~~~~~~~~~~~~
605 This reference is used to get the attribute value of collectd metric from the
606 VES cache. The reference (``<ref type>`` = ``vl``) can be used ONLY inside
607 ``Measurements``, ``ValueItem`` and ``ArrayItem`` tags. Using the reference
608 inside a helper tag is also allowed if the helper tag is located inside the
609 tag where the reference is allowed (e.g.: ``ArrayItem``). The
610 ``<attribute name>`` name corresponds to the table field name described in
611 `Collectd metrics in VES`_ section. For example:
615 name: "{vl.type}-{vl.type_instance}"
618 Collectd notification reference
619 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
621 This reference is used to get the attribute value of received collectd
622 notification. The reference (``<ref type>`` = ``n``) can be used ONLY inside
623 ``Events`` tag. Using the reference inside a helper tag is also allowed if
624 the helper tag is located inside the ``Events`` tag. This type of reference
625 provides the following attributes:
628 The hostname of received collectd notification.
631 The plugin name of received collectd notification.
634 The plugin instance of the received collectd notification.
637 The type name of the received collectd notification.
640 The type instance of the received collectd notification.
643 The severity of the received collectd notification.
646 The message of the received collectd notification.
649 .. note:: The exact value for each attribute depends on the collectd plugin
650 which may generate the notification. Please refer to the
651 `collectd plugin description`_ document to get more details on the specific
658 sourceId: "{n.plugin_instance}"
661 Collectd metric mapping YAML tags
662 ---------------------------------
664 This section describes the YAML tags used to map collectd metric values in the
665 YAML configuration file.
671 This tag is a YAML map which is used to define the VES measurement message. It's
672 allowed to be used multiple times in the document (e.g.: you can define multiple
673 VES messages in one YAML document). This tag works in the same way as `ArrayItem
674 tag`_ does and all keys have the same description/rules.
680 This tag is used to select a collectd metric and get its attribute value using
681 `Collectd metric reference`_. The type of this tag is a YAML array of maps with
682 the possible keys described below.
684 ``SELECT`` (required)
685 Is a YAML map which describes the select metric criteria. Each key name of the
686 map must correspond to the table field name described in `Collectd metrics in VES`_
690 Describes the value to be assigned. If not provided, the default
691 ``!Number "{vl.value}"`` expression is used.
693 ``DEFAULT`` (optional)
694 Describes the default value which will be assigned if no metric is selected
695 by ``SELECT`` criteria.
698 ValueItem tag description example:
702 memoryFree: !ValueItem
707 - VALUE: !Bytes2Kibibytes "{vl.value}"
710 The tag process workflow is described on the figure below.
712 .. figure:: value-item-parse-workflow.png
714 YAML ValueItem tag process workflow
720 This tag is used to select a list of collectd metrics and generate a YAML array
721 of YAML items described by ``ITEM-DESC`` key. If no collectd metrics are
722 selected by the given criteria, the empty array will be returned.
724 ``SELECT`` (optional)
725 Is a YAML map which describes the select metrics criteria. Each key name of
726 the map must correspond to the table field name described in `Collectd
727 metrics in VES`_ section. The value of the key may be regular expression. To
728 enable regular expression in the value, the YAML string containing ``/`` char
729 at the beginning and at the end should be used. For example:
733 plugin: "/^(?!virt).*$/" # selected all metrics except ``virt`` plugin
735 The VES application uses the python RE library to work with regular
736 expression specified in the YAML configuration. Please refer to `python
737 regular expression syntax`_ documentation for more details on a syntax
740 Multiple ``SELECT`` keys are allowed by the tag. If nor ``SELECT`` or
741 ``INDEX-KEY`` key is specified, the VES error is generated.
743 ``INDEX-KEY`` (optional)
744 Is a YAML array which describes the unique fields to be selected by the tag.
745 Each element of array is a YAML string which should be one of the table field
746 name described in `Collectd metrics in VES`_ section. Please note, if this
747 key is used, only fields specified by the key can be used as a collectd
748 reference in the ``ITEM-DESC`` key.
750 ``ITEM-DESC`` (required)
751 Is a YAML map which describes each element of the YAML array generated by
752 the tag. Using ``ArrayItem`` tags and other `Helper YAML tags`_ are also
753 allowed in the definition of the key.
755 In the example below, the ArrayItem tag is used to generate an array of
756 ``ITEM-DESC`` items for each collectd metrics except ``virt`` plugin with
757 unique ``plugin``, ``plugin_instance`` attribute values.
761 Measurements: !ArrayItem
763 plugin: "/^(?!virt).*$/"
768 name: !StripExtraDash "{vl.plugin}-{vl.plugin_instance}"
770 The tag process workflow is described on the figure below.
772 .. figure:: array-item-parse-workflow.png
774 YAML ArrayItem tag process workflow
777 Collectd event mapping YAML tags
778 --------------------------------
780 This section describes the YAML tags used to map the collectd notification to
781 the VES event message in the YAML configuration file.
787 This tag is a YAML map which is used to define the VES event message. It's
788 allowed to be used multiple times in the document (e.g.: you can map multiple
789 collectd notification into VES message in one YAML document). The possible
790 keys of the tag are described below.
792 ``CONDITION`` (optional)
793 Is a YAML map which describes the select metric criteria. Each key name of
794 the map must correspond to the name of attribute provided by `Collectd
795 notification reference`_. If no such key provided, any collectd notification
796 will map the defined YAML message.
798 ``ITEM-DESC`` (required)
799 Is a YAML map which describes the message generated by this tag. Only `Helper
800 YAML tags`_ are allowed in the definition of the key.
802 The example of the VES event message which will be generate by the VES
803 application when collectd notification of the ``virt`` plugin is triggered
814 eventType: Notification
815 sourceId: &event_sourceId "{n.plugin_instance}"
816 sourceName: *event_sourceId
817 lastEpochMicrosec: !Number "{n.time}"
818 startEpochMicrosec: !Number "{n.time}"
820 alarmInterfaceA: !StripExtraDash "{n.plugin}-{n.plugin_instance}"
821 alarmCondition: "{n.severity}"
822 faultFieldsVersion: 1.1
830 This section describes the YAML tags used as utilities for formatting the output
831 message. The YAML configuration process workflow is described on the figure
834 .. figure:: parse-work-flow.png
836 YAML configuration process workflow
839 Convert string to number tag
840 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
842 The ``!Number`` tag is used in YAML configuration file to convert string value into
843 the number type. For instance:
847 lastEpochMicrosec: !Number "3456"
849 The output of the tag will be the JSON number.
854 lastEpochMicrosec: 3456
858 Convert bytes to Kibibytes tag
859 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
861 The ``!Bytes2Kibibytes`` tag is used in YAML configuration file to convert
862 bytes into kibibytes (1 kibibyte = 1024 bytes). For instance:
866 memoryConfigured: !Bytes2Kibibytes 4098
867 memoryConfigured: !Bytes2Kibibytes "1024"
869 The output of the tag will be the JSON number.
879 Convert one value to another tag
880 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
882 The ``!MapValue`` tag is used in YAML configuration file to map one value
883 into another value defined in the configuration. For instance:
893 The output of the tag will be the mapped value.
905 The ``!StripExtraDash`` tag is used in YAML configuration file to strip extra
906 dashes in the string (dashes at the beginning, at the end and double dashes).
911 name: !StripExtraDash string-with--extra-dashes-
913 The output of the tag will be the JSON string with extra dashes removed.
918 name: string-with-extra-dashes
925 #. Only one document can be defined in the same YAML configuration file.
927 #. The collectd notification is not supported by `Kafka collectd plugin`_. Due to
928 this limitation, the collectd notifications cannot be received by the VES
929 application and the defined YAML event will not be generated and sent to the
930 VES collector. Please note, that VES YAML format already supports the events
931 definition and the format is descibed in the document.
934 .. _collectd: http://collectd.org/
935 .. _Kafka: https://kafka.apache.org/
936 .. _`VES`: https://wiki.opnfv.org/display/fastpath/VES+plugin+updates
937 .. _`VES shema definition`: https://gerrit.onap.org/r/gitweb?p=demo.git;a=tree;f=vnfs/VES5.0/evel/evel-test-collector/docs/att_interface_definition;hb=refs/heads/master
938 .. _`PyYAML documentation`: https://pyyaml.org/wiki/PyYAMLDocumentation
939 .. _`collectd plugin description`: https://github.com/collectd/collectd/blob/master/src/collectd.conf.pod
940 .. _`collectd data types file`: https://github.com/collectd/collectd/blob/master/src/types.db
941 .. _`collectd data types description`: https://github.com/collectd/collectd/blob/master/src/types.db.pod
942 .. _`python regular expression syntax`: https://docs.python.org/2/library/re.html#regular-expression-syntax
943 .. _`Kafka collectd plugin`: https://collectd.org/wiki/index.php/Plugin:Write_Kafka