From 2bb8c4857689cabe69d3d2d3d54dffa78d8f4a9f Mon Sep 17 00:00:00 2001 From: Maryam Tahhan Date: Thu, 16 Feb 2017 14:28:05 +0000 Subject: docs: moving to new doc structure Change-Id: I91188deec2bd4e8aa405a9e023acde42b3fb31f7 Signed-off-by: Maryam Tahhan --- docs/development/requirements/02-collectd.rst | 103 ++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100755 docs/development/requirements/02-collectd.rst (limited to 'docs/development/requirements/02-collectd.rst') diff --git a/docs/development/requirements/02-collectd.rst b/docs/development/requirements/02-collectd.rst new file mode 100755 index 00000000..2303fadc --- /dev/null +++ b/docs/development/requirements/02-collectd.rst @@ -0,0 +1,103 @@ +.. 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. + +collectd +~~~~~~~~ +collectd is a daemon which collects system performance statistics periodically +and provides a variety of mechanisms to publish the collected metrics. It +supports more than 90 different input and output plugins. Input plugins retrieve +metrics and publish them to the collectd deamon, while output plugins publish +the data they receive to an end point. collectd also has infrastructure to +support thresholding and notification. + +collectd statistics and Notifications +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Within collectd notifications and performance data are dispatched in the same +way. There are producer plugins (plugins that create notifications/metrics), +and consumer plugins (plugins that receive notifications/metrics and do +something with them). + +Statistics in collectd consist of a value list. A value list includes: + +* Values, can be one of: + + * Derive: used for values where a change in the value since it's last been + read is of interest. Can be used to calculate and store a rate. + + * Counter: similar to derive values, but take the possibility of a counter + wrap around into consideration. + + * Gauge: used for values that are stored as is. + + * Absolute: used for counters that are reset after reading. + +* Value length: the number of values in the data set. + +* Time: timestamp at which the value was collected. + +* Interval: interval at which to expect a new value. + +* Host: used to identify the host. + +* Plugin: used to identify the plugin. + +* Plugin instance (optional): used to group a set of values together. For e.g. + values belonging to a DPDK interface. + +* Type: unit used to measure a value. In other words used to refer to a data + set. + +* Type instance (optional): used to distinguish between values that have an + identical type. + +* meta data: an opaque data structure that enables the passing of additional + information about a value list. "Meta data in the global cache can be used to + store arbitrary information about an identifier" [7]. + +Host, plugin, plugin instance, type and type instance uniquely identify a +collectd value. + +Values lists are often accompanied by data sets that describe the values in more +detail. Data sets consist of: + +* A type: a name which uniquely identifies a data set. + +* One or more data sources (entries in a data set) which include: + + * The name of the data source. If there is only a single data source this is + set to "value". + + * The type of the data source, one of: counter, gauge, absolute or derive. + + * A min and a max value. + +Types in collectd are defined in types.db. Examples of types in types.db: + +.. code-block:: console + + bitrate value:GAUGE:0:4294967295 + counter value:COUNTER:U:U + if_octets rx:COUNTER:0:4294967295, tx:COUNTER:0:4294967295 + +In the example above if_octets has two data sources: tx and rx. + +Notifications in collectd are generic messages containing: + +* An associated severity, which can be one of OKAY, WARNING, and FAILURE. + +* A time. + +* A Message + +* A host. + +* A plugin. + +* A plugin instance (optional). + +* A type. + +* A types instance (optional). + +* Meta-data. -- cgit 1.2.3-korg