Vitrage/Blueprints/rca calculation

Overview

This feature will allow us to track the cause-and-effect path of an alarm raised in OpenStack. In order to track the local causal relationships between alarm-pairs we shall use one or more RCA templates which will specify which alarms cause which alarms. These local relationships between alarm pairs will be updated and persisted in our Topology Graph database.

When we query Vitrage for the RCA of an alarm, we will look for the alarm in our Topology Graph database. If the alarm is found, we then perform a graph walk along all "causes" relationships and return a sub-portion of the Topology Graph database, which represents the (root) cause of this alarm, as well as it's effects on other alarms in the system.

For example, in the figure below, we can see the representation of a topology consisting of a host (compute) hosting a VM, and which is attached to a physical switch. We also see edges labeled "causes" to represent the alarm-pair local causal relationships. Then,

• if we look on an alarm X then we will show that alarm Y caused alarm Z that caused alarm X
• if we look on alarm Z then we will show that alarm Y caused alarm Z
• if we look on alarm Y then we will show that alarm Y caused alarm Z that cause alarm X