.. This work is licensed under a Creative Commons Attribution 4.0 International License. .. http://creativecommons.org/licenses/by/4.0 .. (c) OPNFV, Intel Corporation and others. .. _barometer-ves-userguide: ========================== VES Application User Guide ========================== The Barometer repository contains a python based application for VES (VNF Event Stream) which receives the `collectd`_ specific metrics via `Kafka`_ bus, normalizes the metric data into the VES message format and sends it into the VES collector. The application currently supports pushing platform relevant metrics through the additional measurements field for VES. Collectd has a ``write_kafka`` plugin that sends collectd metrics and values to a Kafka Broker. The VES message formatting application, ves_app.py, receives metrics from the Kafka broker, normalises the data to VES message format for forwarding to VES collector. The VES message formatting application will be simply referred to as the "VES application" within this userguide The VES application can be run in host mode (baremetal), hypervisor mode (on a host with a hypervisor and VMs running) or guest mode(within a VM). The main software blocks that are required to run the VES application demo are: 1. Kafka 2. Collectd 3. VES Application 4. VES Collector Install Kafka Broker -------------------- 1. Dependencies: install JAVA & Zookeeper. Ubuntu 16.04: .. code:: bash $ sudo apt-get install default-jre $ sudo apt-get install zookeeperd $ sudo apt-get install python-pip CentOS: .. code:: bash $ sudo yum update -y $ sudo yum install java-1.8.0-openjdk $ sudo yum install epel-release $ sudo yum install python-pip $ sudo yum install zookeeper $ sudo yum install telnet $ sudo yum install wget .. note:: You may need to add the repository that contains zookeeper. To do so, follow the step below and try to install `zookeeper` again using steps above. Otherwise, skip next step. .. code:: bash $ sudo yum install https://archive.cloudera.com/cdh5/one-click-install/redhat/7/x86_64/cloudera-cdh-5-0.x86_64.rpm Start zookeeper: .. code:: bash $ sudo zookeeper-server start if you get the error message like ``ZooKeeper data directory is missing at /var/lib/zookeeper`` during the start of zookeeper, initialize zookeeper data directory using the command below and start zookeeper again, otherwise skip the next step. .. code:: bash $ sudo /usr/lib/zookeeper/bin/zkServer-initialize.sh No myid provided, be sure to specify it in /var/lib/zookeeper/myid if using non-standalone 2. Test if Zookeeper is running as a daemon. .. code:: bash $ telnet localhost 2181 Type 'ruok' & hit enter. Expected response is 'imok' which means that Zookeeper is up running. 3. Install Kafka .. note:: VES doesn't work with version 0.9.4 of kafka-python. The recommended/tested version is 1.3.3. .. code:: bash $ sudo pip install kafka-python $ wget "https://archive.apache.org/dist/kafka/1.0.0/kafka_2.11-1.0.0.tgz" $ tar -xvzf kafka_2.11-1.0.0.tgz $ sed -i -- 's/#delete.topic.enable=true/delete.topic.enable=true/' kafka_2.11-1.0.0/config/server.properties $ sudo nohup kafka_2.11-1.0.0/bin/kafka-server-start.sh \ kafka_2.11-1.0.0/config/server.properties > kafka_2.11-1.0.0/kafka.log 2>&1 & .. note:: If Kafka server fails to start, please check if the platform IP address is associated with the hostname in the static host lookup table. If it doesn't exist, use the following command to add it. .. code:: bash $ echo "$(ip route get 8.8.8.8 | awk '{print $NF; exit}') $HOSTNAME" | sudo tee -a /etc/hosts 4. Test the Kafka Installation To test if the installation worked correctly there are two scripts, producer and consumer scripts. These will allow you to see messages pushed to broker and receive from broker. Producer (Publish "Hello World"): .. code:: bash $ echo "Hello, World" | kafka_2.11-1.0.0/bin/kafka-console-producer.sh \ --broker-list localhost:9092 --topic TopicTest > /dev/null Consumer (Receive "Hello World"): .. code:: bash $ kafka_2.11-1.0.0/bin/kafka-console-consumer.sh --zookeeper \ localhost:2181 --topic TopicTest --from-beginning --max-messages 1 --timeout-ms 3000 Install collectd ---------------- Install development tools: Ubuntu 16.04: .. code:: bash $ sudo apt-get install build-essential bison autotools-dev autoconf $ sudo apt-get install pkg-config flex libtool CentOS: .. code:: bash $ sudo yum group install 'Development Tools' .. The libkafka installed via the package manager may not work with collectd (due to compilation issue). Thus, it's recommented to use the library installed from sources using latest stable version of libkafka. Install Apache Kafka C/C++ client library: .. code:: bash $ git clone https://github.com/edenhill/librdkafka.git ~/librdkafka $ cd ~/librdkafka $ git checkout -b v0.9.5 v0.9.5 $ ./configure --prefix=/usr $ make $ sudo make install Build collectd with Kafka support: .. code:: bash $ git clone https://github.com/collectd/collectd.git ~/collectd $ cd ~/collectd $ ./build.sh $ ./configure --with-librdkafka=/usr --without-perl-bindings --enable-perl=no $ make && sudo make install .. note:: If installing from git repository ``collectd.conf`` configuration file will be located in directory ``/opt/collectd/etc/``. If installing from via a package manager ``collectd.conf`` configuration file will be located in directory ``/etc/collectd/`` Configure and start collectd. Modify Collectd configuration file ``collectd.conf`` as following: - Within a VM: `Setup VES application (guest mode)`_ - On Host with VMs: `Setup VES application (hypervisor mode)`_ - No Virtualization: `Setup VES application (host mode)`_ Start collectd process as a service as described in :ref:`install-collectd-as-a-service`. Setup VES application (guest mode) ---------------------------------- In this mode Collectd runs from within a VM and sends metrics to the VES collector. .. figure:: ves-app-guest-mode.png VES guest mode setup Install dependencies: .. code:: bash $ sudo pip install pyyaml python-kafka Clone Barometer repo and start the VES application: .. code:: bash $ git clone https://gerrit.opnfv.org/gerrit/barometer $ cd barometer/3rd_party/collectd-ves-app/ves_app $ nohup python ves_app.py --events-schema=yaml/guest.yaml --config=config/ves_app_config.conf > ves_app.stdout.log & Modify Collectd configuration file ``collectd.conf`` as following: .. include:: collectd-ves-guest.conf :code: bash Start collectd process as a service as described in :ref:`install-collectd-as-a-service`. .. note:: The above configuration is used for a localhost. The VES application can be configured to use remote VES collector and remote Kafka server. To do so, the IP addresses/host names needs to be changed in ``collector.conf`` and ``ves_app_config.conf`` files accordingly. Setup VES application (hypervisor mode) ---------------------------------------- This mode is used to collect hypervisor statistics about guest VMs and to send those metrics into the VES collector. Also, this mode collects host statistics and send them as part of the guest VES message. .. figure:: ves-app-hypervisor-mode.png VES hypervisor mode setup Running the VES in hypervisor mode looks like steps described in `Setup VES application (guest mode)`_ but with the following exceptions: - The ``hypervisor.yaml`` configuration file should be used instead of ``guest.yaml`` file when VES application is running. - Collectd should be running on hypervisor machine only. - Addition ``libvirtd`` dependencies needs to be installed on where collectd daemon is running. To install those dependencies, see :ref:`virt-plugin` section of Barometer user guide. - The next (minimum) configuration needs to be provided to collectd to be able to generate the VES message to VES collector. .. note:: At least one VM instance should be up and running by hypervisor on the host. .. include:: collectd-ves-hypervisor.conf :code: bash Start collectd process as a service as described in :ref:`install-collectd-as-a-service`. .. note:: The above configuration is used for a localhost. The VES application can be configured to use remote VES collector and remote Kafka server. To do so, the IP addresses/host names needs to be changed in ``collector.conf`` and ``ves_app_config.conf`` files accordingly. .. note:: The list of the plugins can be extented depends on your needs. Setup VES application (host mode) ---------------------------------- This mode is used to collect platform wide metrics and to send those metrics into the VES collector. It is most suitable for running within a baremetal platform. Install dependencies: .. code:: bash $ sudo pip install pyyaml Clone Barometer repo and start the VES application: .. code:: bash $ git clone https://gerrit.opnfv.org/gerrit/barometer $ cd barometer/3rd_party/collectd-ves-app/ves_app $ nohup python ves_app.py --events-schema=yaml/host.yaml --config=config/ves_app_config.conf > ves_app.stdout.log & .. figure:: ves-app-host-mode.png VES Native mode setup Modify collectd configuration file ``collectd.conf`` as following: .. include:: collectd-ves-host.conf :code: bash Start collectd process as a service as described in :ref:`install-collectd-as-a-service`. .. note:: The above configuration is used for a localhost. The VES application can be configured to use remote VES collector and remote Kafka server. To do so, the IP addresses/host names needs to be changed in ``collector.conf`` and ``ves_app_config.conf`` files accordingly. .. note:: The list of the plugins can be extented depends on your needs. .. _Setup VES Test Collector: Setup VES Test Collector ------------------------ .. note:: Test Collector setup is required only for VES application testing purposes. Install dependencies: .. code:: bash $ sudo pip install jsonschema Clone VES Test Collector: .. code:: bash $ git clone https://github.com/att/evel-test-collector.git ~/evel-test-collector Modify VES Test Collector config file to point to existing log directory and schema file: .. code:: bash $ sed -i.back 's/^\(log_file[ ]*=[ ]*\).*/\1collector.log/' ~/evel-test-collector/config/collector.conf $ sed -i.back 's/^\(schema_file[ ]*=.*\)event_format_updated.json$/\1CommonEventFormat.json/' ~/evel-test-collector/config/collector.conf Start VES Test Collector: .. code:: bash $ cd ~/evel-test-collector/code/collector $ nohup python ./collector.py --config ../../config/collector.conf > collector.stdout.log & VES application configuration description ----------------------------------------- **Details of the Vendor Event Listener REST service** REST resources are defined with respect to a ``ServerRoot``:: ServerRoot = https://{Domain}:{Port}/{optionalRoutingPath} REST resources are of the form:: {ServerRoot}/eventListener/v{apiVersion}` {ServerRoot}/eventListener/v{apiVersion}/{topicName}` {ServerRoot}/eventListener/v{apiVersion}/eventBatch` Within the VES directory (``3rd_party/collectd-ves-app/ves_app/config``) there is a configuration file called ``ves_app_conf.conf``. The description of the configuration options are described below: **Domain** *"host"* VES domain name. It can be IP address or hostname of VES collector (default: ``127.0.0.1``) **Port** *port* VES port (default: ``30000``) **Path** *"path"* Used as the "optionalRoutingPath" element in the REST path (default: ``vendor_event_listener``) **Topic** *"path"* Used as the "topicName" element in the REST path (default: ``example_vnf``) **UseHttps** *true|false* Allow application to use HTTPS instead of HTTP (default: ``false``) **Username** *"username"* VES collector user name (default: empty) **Password** *"passwd"* VES collector password (default: empty) **SendEventInterval** *interval* This configuration option controls how often (sec) collectd data is sent to Vendor Event Listener (default: ``20``) **ApiVersion** *version* Used as the "apiVersion" element in the REST path (default: ``3``) **KafkaPort** *port* Kafka Port (Default ``9092``) **KafkaBroker** *host* Kafka Broker domain name. It can be an IP address or hostname of local or remote server (default: ``localhost``) VES YAML configuration format ----------------------------- The format of the VES message is generated by the VES application based on the YAML schema configuration file provided by user via ``--events-schema`` command-line option of the application. .. note:: Use ``--help`` option of VES application to see the description of all available options .. note:: The detailed installation guide of the VES application is described in the `VES Application User Guide`_. The message defined by YAML schema should correspond to format defined in `VES shema definition`_. .. warning:: This section doesn't explain the YAML language itself, so the knowledge of the YAML language is required before continue reading it! Since, the VES message output is a JSON format, it's recommended to understand how YAML document is converted to JSON before starting to create a new YAML definition for the VES. E.g.: The following YAML document: .. code:: yaml --- additionalMeasurements: plugin: somename instance: someinstance will be converted to JSON like this: .. code:: json { "additionalMeasurements": { "instance": "someinstance", "plugin": "somename" } } .. note:: The `YAML syntax` section of `PyYAML documentation`_ can be used as a reference for this. VES message types ----------------- The VES agent can generate two type of messages which are sent to the VES collector. Each message type must be specified in the YAML configuration file using a specific YAML tag. Measurements This type is used to send a message defined in YAML configuration to the VES collector with a specified interval (default is 20 sec and it's configurable via command line option of the application). This type can be specified in the configuration using ``!Measurements`` tag. For instance: .. code:: yaml --- # My comments My Host Measurements: !Measurements ... # message definition Events This type is used to send a message defined in YAML configuration to the VES collector when collectd notification is received from Kafka bus (collectd ``write_kafka`` plugin). This type can be specified in the configuration using ``!Events`` tag. For instance: .. code:: yaml --- # My comments My Events: !Events ... # event definition Collectd metrics in VES ----------------------- The VES application caches collectd metrics received via Kafka bus. The data is stored in a table format. It's important to know it before mapping collectd metric values to message defined in YAML configuration file. VES collectd metric cache example: +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | host | plugin | plugin_instance | type | type_instace | time | value | ds_name | interval | +===========+===========+====================+===========+================+===================+========+=========+==========+ | localhost | cpu | | percent | user | 1509535512.30567 | 16 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | localhost | memory | | memory | free | 1509535573.448014 | 798456 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | localhost | interface | | eth0 | if_packets | 1509544183.956496 | 253 | rx | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | percent | virt_cpu_total | 1509544402.378035 | 0.2 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | memory | rss | 1509544638.55119 | 123405 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | 7ec333e7 | virt | Ubuntu-12.04.5-LTS | if_octets | vnet1 | 1509544646.27108 | 67 | tx | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | cc659a52 | virt | Ubuntu-16.04 | percent | virt_cpu_total | 1509544745.617207 | 0.3 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | cc659a52 | virt | Ubuntu-16.04 | memory | rss | 1509544754.329411 | 4567 | value | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ | cc659a52 | virt | Ubuntu-16.04 | if_octets | vnet0 | 1509544760.720381 | 0 | rx | 10 | +-----------+-----------+--------------------+-----------+----------------+-------------------+--------+---------+----------+ It's possible from YAML configuration file to refer to any field of any row of the table via special YAML tags like ``ValueItem`` or ``ArrayItem``. See the `Collectd metric reference`_ reference for more details. .. note:: The `collectd data types file`_ contains map of ``type`` to ``ds_name`` field. It can be used to get possible value for ``ds_name`` field. See the `collectd data types description`_ for more details on collectd data types. Aging of collectd metric ~~~~~~~~~~~~~~~~~~~~~~~~ If the metric will not be updated by the collectd during the double metric interval time, it will be removed (aged) from VES internal cache. VES YAML references ------------------- There are four type of references supported by the YAML format: System, Config, Collectd metric and Collectd notification. The format of the reference is the following: .. code:: yaml "{.}" .. note:: Possible values for ```` and ```` are described in farther sections. System reference ~~~~~~~~~~~~~~~~ This reference is used to get system statistics like time, date etc. The system reference (```` = ``system``) can be used in any place of the YAML configuration file. This type of reference provides the following attributes: ``hostname`` The name of the host where VES application is running. ``id`` Unique ID during VES application runtime. ``time`` Current time in seconds since the Epoch. For example ``1509641411.631951``. ``date`` Current date in ISO 8601 format, ``YYYY-MM-DD``. For instance ``2017-11-02``. For example: .. code:: yaml Date: "{system.date}" Config reference ~~~~~~~~~~~~~~~~ This reference is used to get VES configuration described in `VES application configuration description`_ sectoin. The reference (```` = ``config``) can be used in any place of the YAML configuration file. This type of reference provides the following attributes: ``interval`` Measurements dispatch interval. It referenses to ``SendEventInterval`` configuration of the VES application. For example: .. code:: yaml Interval: "{config.interval}" Collectd metric reference ~~~~~~~~~~~~~~~~~~~~~~~~~ This reference is used to get the attribute value of collectd metric from the VES cache. The reference (```` = ``vl``) can be used ONLY inside ``Measurements``, ``ValueItem`` and ``ArrayItem`` tags. Using the reference inside a helper tag is also allowed if the helper tag is located inside the tag where the reference is allowed (e.g.: ``ArrayItem``). The ```` name corresponds to the table field name described in `Collectd metrics in VES`_ section. For example: .. code:: yaml name: "{vl.type}-{vl.type_instance}" Collectd notification reference ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This reference is used to get the attribute value of received collectd notification. The reference (```` = ``n``) can be used ONLY inside ``Events`` tag. Using the reference inside a helper tag is also allowed if the helper tag is located inside the ``Events`` tag. This type of reference provides the following attributes: ``host`` The hostname of received collectd notification. ``plugin`` The plugin name of received collectd notification. ``plugin_instance`` The plugin instance of the received collectd notification. ``type`` The type name of the received collectd notification. ``type_instance`` The type instance of the received collectd notification. ``severity`` The severity of the received collectd notification. ``message`` The message of the received collectd notification. .. note:: The exact value for each attribute depends on the collectd plugin which may generate the notification. Please refer to the `collectd plugin description`_ document to get more details on the specific collectd plugin. YAML config example: .. code:: yaml sourceId: "{n.plugin_instance}" Collectd metric mapping YAML tags --------------------------------- This section describes the YAML tags used to map collectd metric values in the YAML configuration file. Measurements tag ~~~~~~~~~~~~~~~~ This tag is a YAML map which is used to define the VES measurement message. It's allowed to be used multiple times in the document (e.g.: you can define multiple VES messages in one YAML document). This tag works in the same way as `ArrayItem tag`_ does and all keys have the same description/rules. ValueItem tag ~~~~~~~~~~~~~ This tag is used to select a collectd metric and get its attribute value using `Collectd metric reference`_. The type of this tag is a YAML array of maps with the possible keys described below. ``SELECT`` (required) Is a YAML map which describes the select metric criteria. Each key name of the map must correspond to the table field name described in `Collectd metrics in VES`_ section. ``VALUE`` (optional) Describes the value to be assigned. If not provided, the default ``!Number "{vl.value}"`` expression is used. ``DEFAULT`` (optional) Describes the default value which will be assigned if no metric is selected by ``SELECT`` criteria. ValueItem tag description example: .. code:: yaml memoryFree: !ValueItem - SELECT: plugin: memory type: memory type_instance: rss - VALUE: !Bytes2Kibibytes "{vl.value}" - DEFAULT: 0 The tag process workflow is described on the figure below. .. figure:: value-item-parse-workflow.png YAML ValueItem tag process workflow ArrayItem tag ~~~~~~~~~~~~~ This tag is used to select a list of collectd metrics and generate a YAML array of YAML items described by ``ITEM-DESC`` key. If no collectd metrics are selected by the given criteria, the empty array will be returned. ``SELECT`` (optional) Is a YAML map which describes the select metrics criteria. Each key name of the map must correspond to the table field name described in `Collectd metrics in VES`_ section. The value of the key may be regular expression. To enable regular expression in the value, the YAML string containing ``/`` char at the beginning and at the end should be used. For example: .. code:: yaml plugin: "/^(?!virt).*$/" # selected all metrics except ``virt`` plugin The VES application uses the python RE library to work with regular expression specified in the YAML configuration. Please refer to `python regular expression syntax`_ documentation for more details on a syntax used by the VES. Multiple ``SELECT`` keys are allowed by the tag. If nor ``SELECT`` or ``INDEX-KEY`` key is specified, the VES error is generated. ``INDEX-KEY`` (optional) Is a YAML array which describes the unique fields to be selected by the tag. Each element of array is a YAML string which should be one of the table field name described in `Collectd metrics in VES`_ section. Please note, if this key is used, only fields specified by the key can be used as a collectd reference in the ``ITEM-DESC`` key. ``ITEM-DESC`` (required) Is a YAML map which describes each element of the YAML array generated by the tag. Using ``ArrayItem`` tags and other `Helper YAML tags`_ are also allowed in the definition of the key. In the example below, the ArrayItem tag is used to generate an array of ``ITEM-DESC`` items for each collectd metrics except ``virt`` plugin with unique ``plugin``, ``plugin_instance`` attribute values. .. code:: yaml Measurements: !ArrayItem - SELECT: plugin: "/^(?!virt).*$/" - INDEX-KEY: - plugin - plugin_instance - ITEM-DESC: name: !StripExtraDash "{vl.plugin}-{vl.plugin_instance}" The tag process workflow is described on the figure below. .. figure:: array-item-parse-workflow.png YAML ArrayItem tag process workflow Collectd event mapping YAML tags -------------------------------- This section describes the YAML tags used to map the collectd notification to the VES event message in the YAML configuration file. Events tag ~~~~~~~~~~ This tag is a YAML map which is used to define the VES event message. It's allowed to be used multiple times in the document (e.g.: you can map multiple collectd notification into VES message in one YAML document). The possible keys of the tag are described below. ``CONDITION`` (optional) Is a YAML map which describes the select metric criteria. Each key name of the map must correspond to the name of attribute provided by `Collectd notification reference`_. If no such key provided, any collectd notification will map the defined YAML message. ``ITEM-DESC`` (required) Is a YAML map which describes the message generated by this tag. Only `Helper YAML tags`_ are allowed in the definition of the key. The example of the VES event message which will be generate by the VES application when collectd notification of the ``virt`` plugin is triggered is described below. .. code:: yaml --- Virt Event: !Events - ITEM-DESC: event: commonEventHeader: domain: fault eventType: Notification sourceId: &event_sourceId "{n.plugin_instance}" sourceName: *event_sourceId lastEpochMicrosec: !Number "{n.time}" startEpochMicrosec: !Number "{n.time}" faultFields: alarmInterfaceA: !StripExtraDash "{n.plugin}-{n.plugin_instance}" alarmCondition: "{n.severity}" faultFieldsVersion: 1.1 - CONDITION: plugin: virt Helper YAML tags ---------------- This section describes the YAML tags used as utilities for formatting the output message. The YAML configuration process workflow is described on the figure below. .. figure:: parse-work-flow.png YAML configuration process workflow Convert string to number tag ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ``!Number`` tag is used in YAML configuration file to convert string value into the number type. For instance: .. code:: yaml lastEpochMicrosec: !Number "3456" The output of the tag will be the JSON number. .. code:: json { lastEpochMicrosec: 3456 } Convert bytes to Kibibytes tag ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ``!Bytes2Kibibytes`` tag is used in YAML configuration file to convert bytes into kibibytes (1 kibibyte = 1024 bytes). For instance: .. code:: yaml memoryConfigured: !Bytes2Kibibytes 4098 memoryConfigured: !Bytes2Kibibytes "1024" The output of the tag will be the JSON number. .. code:: json { memoryConfigured: 4 memoryConfigured: 1 } Convert one value to another tag ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ``!MapValue`` tag is used in YAML configuration file to map one value into another value defined in the configuration. For instance: .. code:: yaml Severity: !MapValue VALUE: Failure TO: Failure: Critical Error: Warnign The output of the tag will be the mapped value. .. code:: json { Severity: Critical } Strip extra dash tag ~~~~~~~~~~~~~~~~~~~~ The ``!StripExtraDash`` tag is used in YAML configuration file to strip extra dashes in the string (dashes at the beginning, at the end and double dashes). For example: .. code:: yaml name: !StripExtraDash string-with--extra-dashes- The output of the tag will be the JSON string with extra dashes removed. .. code:: json { name: string-with-extra-dashes } Limitations ----------- #. Only one document can be defined in the same YAML configuration file. #. The collectd notification is not supported by `Kafka collectd plugin`_. Due to this limitation, the collectd notifications cannot be received by the VES application and the defined YAML event will not be generated and sent to the VES collector. Please note, that VES YAML format already supports the events definition and the format is descibed in the document. .. _collectd: http://collectd.org/ .. _Kafka: https://kafka.apache.org/ .. _`VES`: https://wiki.opnfv.org/display/fastpath/VES+plugin+updates .. _`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 .. _`PyYAML documentation`: https://pyyaml.org/wiki/PyYAMLDocumentation .. _`collectd plugin description`: https://github.com/collectd/collectd/blob/master/src/collectd.conf.pod .. _`collectd data types file`: https://github.com/collectd/collectd/blob/master/src/types.db .. _`collectd data types description`: https://github.com/collectd/collectd/blob/master/src/types.db.pod .. _`python regular expression syntax`: https://docs.python.org/2/library/re.html#regular-expression-syntax .. _`Kafka collectd plugin`: https://collectd.org/wiki/index.php/Plugin:Write_Kafka