Chapter 13

1. A service-level indicator (SLI) is a type of metric that allows us to quantify the perceived quality of the service from the perspective of the end user (for example, metrics such as availability, throughput, and latency). A service-level objective (SLO) is the range of values for some SLIs that allow us to deliver a particular level of service to an end user or customer.
2. A service-level agreement (SLA) is an implicit or explicit contract between a service provider and one or more service consumers. The SLA outlines a set of SLOs that have to be met and the consequences (financial or not) for meeting and failing to meet them.
3. In a push-based metrics collection system, the metric-producing clients connect to the metrics collection and aggregation service over a TCP or UDP connection and publish their metrics. In a pull-based system, the metrics collection system, at...