This page describes the best practices for OPA agent deployment.
When will decisions be dropped?
SLP has a configurable queue size. If SLP cannot keep up with the decisions rate, it will send errors back to OPA. OPA will buffer these rejected decisions in memory. If the buildup is too much, then OPA will Out Of Memory (OOM) at some point, K8s will restart it and things will get to normal. OOM is easier to identify or monitor than silent drop of decisions somewhere in SLP queue.