Micrometer Metrics & Export

publishPercentiles computes percentiles inside each instance (not mergeable across instances). publishPercentileHistogram exports histogram buckets the backend aggregates to compute percentiles. serviceLevelObjectives adds explicit boundary buckets so you can measure the fraction meeting a target.

Expose a MeterBinder @Bean and Boot binds it to the registry automatically, just like the built-ins. To add tags to every meter (built-in included) register a MeterRegistryCustomizer or MeterFilter.commonTags. Prefer a MeterBinder when you're exposing the state of a long-lived resource.

Use @Timed/@Counted for quick, low-boilerplate, method-level metrics on Spring beans. Use programmatic Micrometer when you need dynamic tags, to time part of a method, or to avoid proxy limits. At scale watch tag cardinality, the AOP proxy constraints, and consistent naming.

Use Prometheus scraping for stable, discoverable services (free liveness via failed scrapes, monitor controls timing). Use OTLP push for ephemeral/serverless or unreachable apps. Often run both through an OpenTelemetry Collector, migrating incrementally.

Standardize a common-tag contract (application, env, region, instance) via a shared library, enforce tag hygiene with shared MeterFilters (ignoreTags, replaceTagValues, maximumAllowableTags as a backstop), keep ids in logs/traces, and monitor active-series cardinality as an SLO. Ship it as an auto-configured starter so every service inherits it by default.