84 lines
3.5 KiB
XML
84 lines
3.5 KiB
XML
<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
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xml:id="metering-service">
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<title>Telemetry</title>
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<para>The Telemetry module:</para>
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<para>
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<itemizedlist>
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<listitem>
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<para>Efficiently collects the metering data about the CPU
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and network costs.</para>
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</listitem>
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<listitem>
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<para>Collects data by monitoring notifications sent from
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services or by polling the infrastructure.</para>
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</listitem>
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<listitem>
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<para>Configures the type of collected data to meet
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various operating requirements. Accessing and inserting the
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metering data through the REST API.</para>
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</listitem>
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<listitem>
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<para>Expands the framework to collect custom usage data
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by additional plug-ins.</para>
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</listitem>
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<listitem>
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<para>Produces signed metering messages that cannot be
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repudiated.</para>
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</listitem>
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</itemizedlist>
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</para>
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<para>The system consists of the following basic
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components:</para>
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<itemizedlist>
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<listitem>
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<para>A compute agent (<systemitem class="service"
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>ceilometer-agent-compute</systemitem>). Runs on each
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compute node and polls
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for resource utilization statistics. There may be other
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types of agents in the future, but for now we will focus
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on creating the compute agent.</para>
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</listitem>
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<listitem>
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<para>A central agent (<systemitem class="service"
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>ceilometer-agent-central</systemitem>). Runs on a central
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management server
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to poll for resource utilization statistics for resources
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not tied to instances or compute nodes.</para>
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</listitem>
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<listitem>
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<para>A collector (<systemitem class="service"
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>ceilometer-collector</systemitem>). Runs on one or more
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central management
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servers to monitor the message queues (for notifications
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and for metering data coming from the agent). Notification
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messages are processed and turned into metering messages
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and sent back out onto the message bus using the
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appropriate topic. Telemetry messages are written to the
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data store without modification.</para>
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</listitem>
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<listitem>
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<para>An alarm notifier (<systemitem class="service"
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>ceilometer-alarm-notifier</systemitem>). Runs on one or more
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central management servers to allow settting alarms based on
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threshold evaluation for a collection of samples.
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</para>
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</listitem>
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<listitem>
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<para>A data store. A database capable of handling
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concurrent writes (from one or more collector instances)
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and reads (from the API server).</para>
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</listitem>
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<listitem>
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<para>An API server (<systemitem class="service"
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>ceilometer-api</systemitem>). Runs on one or more central
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management
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servers to provide access to the data from the data store.</para>
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</listitem>
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</itemizedlist>
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<para>These services communicate by using the standard OpenStack
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messaging bus. Only the collector and API server have access
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to the data store.</para>
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</section>
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