一、添加依赖

Spring Boot 应用和Prometheus 集成，你需要增加micrometer-registry-prometheus依赖。

<!-- Micrometer Prometheus registry  -->

<dependency>

    <groupId>io.micrometer</groupId>

    <artifactId>micrometer-registry-prometheus</artifactId>

</dependency>

添加上述依赖项之后，Spring Boot 将会自动配置 PrometheusMeterRegistry 和 CollectorRegistry来以Prometheus 可以抓取的格式（即上文提到的 Metrics 格式）收集和导出指标数据。

所有的相关数据，都会在Actuator 的 /prometheus端点暴露出来。Prometheus 可以抓取该端点以定期获取度量标准数据。

1.1 Actuator 的 /prometheus端点

加micrometer-registry-prometheus依赖后，我们访问http://localhost:8080/actuator/prometheus地址，可以看到一下内容：

# HELP jvm_buffer_total_capacity_bytes An estimate of the total capacity of the buffers in this pool

# TYPE jvm_buffer_total_capacity_bytes gauge

jvm_buffer_total_capacity_bytes{id="direct",} 90112.0

jvm_buffer_total_capacity_bytes{id="mapped",} 0.0

# HELP tomcat_sessions_expired_sessions_total

# TYPE tomcat_sessions_expired_sessions_total counter

tomcat_sessions_expired_sessions_total 0.0

# HELP jvm_classes_unloaded_classes_total The total number of classes unloaded since the Java virtual machine has started execution

# TYPE jvm_classes_unloaded_classes_total counter

jvm_classes_unloaded_classes_total 1.0

# HELP jvm_buffer_count_buffers An estimate of the number of buffers in the pool

# TYPE jvm_buffer_count_buffers gauge

jvm_buffer_count_buffers{id="direct",} 11.0

jvm_buffer_count_buffers{id="mapped",} 0.0

# HELP system_cpu_usage The "recent cpu usage" for the whole system

# TYPE system_cpu_usage gauge

system_cpu_usage 0.0939447637893599

# HELP jvm_gc_max_data_size_bytes Max size of old generation memory pool

# TYPE jvm_gc_max_data_size_bytes gauge

jvm_gc_max_data_size_bytes 2.841116672E9

# 此处省略超多字...

这些都是按照上文提到的 Metrics 格式组织起来的程序监控指标数据。

metric name>{<label name>=<label value>, ...}

二、Prometheus 配置

配置Prometheus 去收集/actuator/prometheus的指标数据。

# my global config

global:

  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.

  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.

  # scrape_timeout is set to the global default (10s).

# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.

rule_files:

  # - "first_rules.yml"

  # - "second_rules.yml"

# A scrape configuration containing exactly one endpoint to scrape:

# Here it's Prometheus itself.

scrape_configs:

  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.

  - job_name: 'prometheus'

    # metrics_path defaults to '/metrics'

    # scheme defaults to 'http'.

    static_configs:

    - targets: ['localhost:9090']

  # demo job

  -  job_name: 'springboot-actuator-prometheus-test' # job name

     metrics_path: '/actuator/prometheus' # 指标获取路径

     scrape_interval: 5s # 间隔

     basic_auth: # Spring Security basic auth

       username: 'actuator'

       password: 'actuator'

     static_configs:

     - targets: ['10.60.45.113:8080'] # 实例的地址，默认的协议是http