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For the purposes of Platform Service Assurance, it's important to distinguish between metrics and events as well as how they are measured (from a timing perspective).
A metric (at any point in time) represents a measurement of an aspect of a particular platform resource for the purpose of monitoring. For Metric is a (standard) definition of a quantity describing the performance and/or reliability of a monitored function, which has an intended utility and is carefully specified to convey the exact meaning of the measured value. A measured value of a metric is produced in an assessment of a monitored function according to a method of measurement. For example the number of dropped packets for a networking interface is a metric.
An Event can be thought of as a notification about a notable condition (usually a message with an associated severity and time). Events are used to notify monitoring systems of the occurrence of something that they should be aware of. For example, is defined as an important state change in a monitored function. The monitor system is notified that an event has occurred using a message with a standard format. The Event notification describes the significant aspects of the event, such as the name and ID of the monitored function, the type of event, and the time the event occurred. For example, an event notification would take place if the link status of a networking device on a compute node suddenly changes from up to down on a node hosting VNFs in an NFV deployment.
Information to be collected in conjunction with NFVI Metrics/Events
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