Trying to understand the doc for using enablePrometheusMerge and env var ISTIO_PROMETHEUS_ANNOTATIONS.
Does not mention what port the users app should be using in order for the merge with Envoy metrics to work. What port should be used?
The enablePrometheusMerge will automatically add the annotations:
prometheus.io path: /stats/prometheus prometheus.io port: "15020" prometheus.io scrape: "true"
That is the “merged” metrics port, but what to understand the envoy and app ports that feed into that.
From the code, looks like that env VAR ISTIO_PROMETHEUS_ANNOTATIONS is used and default to “80:/metrics”
That doc is also missing: https://istio.io/latest/docs/reference/commands/pilot-agent/#envvars