2. Metrics Monitoring: Spring Boot 3 -- OpenTelemetry -- Prometheus -- Grafana 

Thank you very much 😍! your comment made my day, I really appreciate that 🥰

glad you found it useful, thanks so much for your nice words!

many thanks, I didn't use any special extension, and they're just java classes and supposed to be compiled and run the same for jvm.

if you look at the collector in our docker-compose file, you will see it exposed 2 ports: 8888 and 8889. 8888 is the default port that exposes the metrics of this collector itself, you can ignore it since we don't use it in this video. Let's talk about port 8889, this's actually the port that we define for our "prometheus exporters" in otel-collector.yml. We defined "prometheus exporters" at port 8889, so we had port 8889 in docker-compose file, so if "prometheus exporters" is at port X, we should had port X in in docker-compose file (so it's not required to be 8889). And to make a "prometheus exporters" active, we need to add it into a pipeline in otel-collector.yml. With that being set up, now OtelCollector opens port X (8889 for example) for Prometheus scraping data. Then in prometheus.yaml, let's set the scraping configuration to port X (8889). Hope you got the idea and I think you cannot see your custom metrics due to that as well. In this series, we also create a custom histogram metrics, hope it can help!

let's take a look at the diagram, you'll see the arrow from hello-service to collector, it means service "pushes" metrics to collector. On the other side, the arrow is from prometheus to collector, it means prometheus "pulls" (scrape) metrics from collector. Hope it will help you in later videos!

Yeah man got it

Thanks so much for watching the video, you can see the log of OtelCollector to see whether it starts successfully or not. Notice at some lines like "port xxxx" opened for grpc or http. For your case, be sure that: at receivers part of otel config file, you have specified: otlp.protocols.http. By default: http will open 0.0.0.0:4318 which the receiver is going to receive data. Similar to 8889, which is the port that Prometheus will pull data.

Bro, you need to check whether your Otel Collector run successfully or not by `docker logs`. In this video since we've been using http, you should see this line of log `Starting HTTP server "endpoint": "0.0.0.0:4318"`. Secondly, you should make sure you exposed this port to your local machine by specifying port "4318:4318" in otel-collector in your Dockerfile.

The error was a missing 's' hahahahaa Thanks very much brother!