Introduction to monitoring from Java Touching Prometheus

What is Prometheus?

Pull type monitoring system. OSS. A system that can monitor memory and CPU usage.

What is a pull-type monitoring system?

Normal surveillance systems (Meckerel, Sensu, etc.) Install an agent on the monitoring side and send information to the monitoring server.

On the contrary, the Pull type acquires information from the side monitored by the monitoring server.

merit and demerit

Push type

[merit] ・ Easy to install the app on the monitoring target -There are few changes in server settings even if the number of monitoring targets increases.

[Demerit] -When the amount of monitoring increases, the load on the monitoring server increases.

Pull type

[merit] ・ It is easier to see that the monitoring target is down than the Push type. -The load on the monitoring server is lower than Push

[Demerit] -You have to set the endpoint to be monitored. It's not just a simple installation. ・ When the number of monitoring targets increases, it is necessary to set each time.

This goal

In Spring application, link data to Promethus, Display nicely with Grafana.

procedure

Create Promethus endpoint in Spring

Added Spring Actuator from Spring Initializr [https://start.spring.io/]. Spring Actuator will be able to check Spring dumps and health checks.

Set Micrometer Registry Prometheus as a dependency. [ https://mvnrepository.com/artifact/io.micrometer/micrometer-registry-prometheus ]

Maven Repository:.png

Open the endpoint from the property file.

`application.properties`


#Full open
management.endpoints.web.exposure.include=*

Start the application and confirm that the endpoint is created.

http://localhost:8080/actuator/prometheus

Prometheus settings

Can be set with the following YML

`prometheus.yml`



global:
  #Frequency of target acquisition
  scrape_interval:     10s
  evaluation_interval: 10s

#Monitoring target settings
scrape_configs:
  #Spring Boot App Exporter monitoring settings
  - job_name: 'springboot'
    metrics_path: '/actuator/prometheus'
    static_configs:
      - targets: ['web:8080']
        labels:
          group: 'docker-springboot'

Launch Prometheus / Grafana / App

Start with Docker Compose.

`docker-compose.yml`


version: '3.1'
services:

  web:
    build: app/
    ports:
      - "8080:8080"

  monitor:
    build: prometheus/
    ports:
      - "9090:9090"
    depends_on:
      - "web"

  grafana:
    image: grafana/grafana
    ports:
      - "3000:3000"