使用 Prometheus 监控 Pod 内部

Question

I want to know if it's possible to get metrics for the services inside the pods using Prometheus.

I don't mean monitoring the pods but the processes inside those pods . For example, containers which have apache or nginx running inside them along other main services, so I can retrieve metrics for the web server and the other main service (for example a wordpress image which aso comes with an apache configured).

The cluster already has running kube-state-metrics, node-exporter and blackbox exporter.

Is it possible? If so, how can I manage to do it?

Thanks in advance

Answer 1

Prometheus works by scraping an HTTP endpoint that provides the actual metrics. That's where you get the term "exporter". So if you want to get metrics from the processes running inside of pods you have three primary steps:

1. You must modify those processes to export the metrics you care about. This is inherently something that must be custom for each kind of application. The good news is that there are lots of pre-built ones including things like nginx and apache that you mention. Most application frameworks also have capability to export prometheus metrics. ex: Microprofile , Quarkus , and many more.
2. You must then modify your pod definition to expose the HTTP endpoint that those processes are now providing. Very straightfoward, but will depend on the configuration you specify for your exporters.
3. You must then modify your Prometheus to scrape those targets. This will depend on your monitoring stack. For Openshift you will find the docs here for enabling user workload monitoring , and here for providing exporter details.