Prometheus server
Targets, Units
Monitor Linux, Apache Server, Single Applicaations, service like Database, Targets has units to measure. Human readable metrics
Exporter - scrapes and exports data from the application. Prometheus is pull based monitoring solution. It can also do push with some configuration. Data is received on the /metrics endpoint of each application. Type – 3 metrics types
When you install helm 3 chart, this happens
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm install [RELEASE_NAME] prometheus-community/kube-prometheus-stack
2 Stateful Sets - 1 prometheus, 1 alertmanager 3 deployments - 1 grafana, 1 promethus operator, kube state metrics(out of the box) 1 daemonset - Node Exporter - runs on the every single worker Node(daemonset) - translates all data into prometheus data for prometheous to be scraped several services, several pods multiple configmap, secrets are created
CRD - custom resource definitions Prometheus includes crd pre built.
Sample application mongodb exposed to be monitored by prometheus, grafana. Pull metrics are gathered. Prometheus server finds the exporters and targets.
Create Prometheus UI, Grafana using PromQL.
There are many supported exporters for prometheus. https://prometheus.io/docs/instrumenting/exporters/
We get a mongodb exporter. Docker image for the mongo exporter.
Deploying an exporter
Prometheus must know the application is present to enable scraping. Create service monitor.
Configurations can be configured using a helm chart. https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus-mongodb-exporter
this chart is used.
release: prometheus needs to be added. Then prometheus can recognize the the service monitor.kubectl port-forward deployment/prometheus-grafana 3000
kubectl port-forward service/prometheus-kube-prometheus-prometheus 9090