Prometheus

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Prometheus

监控指标的 Prometheus 映射关系

对于 Metric Name 为 name, Tags 为 K1=V1, ..., Kn=Vn 的监控指标有如下映射，其中 value 为具体值

监控指标类型	映射关系
Counter	name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value
AutoGauge、Gauge	name{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value
Histogram	name_max{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_sum{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_count{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", quantile="0.5"} value name{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", quantile="0.99"} value
Rate	name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", rate="m1"} value name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", rate="m5"} value name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", rate="m15"} value name_total{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", rate="mean"} value
Timer	name_seconds_max{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_seconds_sum{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_seconds_count{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn"} value name_seconds{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", quantile="0.5"} value value name_seconds{cluster="clusterName", nodeType="nodeType", nodeId="nodeId",k1="V1" , ..., Kn="Vn", quantile="0.99"} value

修改配置文件

以 DataNode 为例，修改 iotdb-system.properties 配置文件如下：

dn_metric_reporter_list=PROMETHEUS
dn_metric_level=CORE
dn_metric_prometheus_reporter_port=9091

启动 IoTDB DataNode
打开浏览器或者用curl 访问 http://servier_ip:9091/metrics, 就能得到如下 metric 数据：

...
# HELP file_count
# TYPE file_count gauge
file_count{name="wal",} 0.0
file_count{name="unseq",} 0.0
file_count{name="seq",} 2.0
...

Prometheus + Grafana

如上所示，IoTDB 对外暴露出标准的 Prometheus 格式的监控指标数据，可以使用 Prometheus 采集并存储监控指标，使用 Grafana
可视化监控指标。

IoTDB、Prometheus、Grafana三者的关系如下图所示:

IoTDB在运行过程中持续收集监控指标数据。
Prometheus以固定的间隔（可配置）从IoTDB的HTTP接口拉取监控指标数据。
Prometheus将拉取到的监控指标数据存储到自己的TSDB中。
Grafana以固定的间隔（可配置）从Prometheus查询监控指标数据并绘图展示。

从交互流程可以看出，我们需要做一些额外的工作来部署和配置Prometheus和Grafana。

比如，你可以对Prometheus进行如下的配置（部分参数可以自行调整）来从IoTDB获取监控数据

job_name: pull-metrics
honor_labels: true
honor_timestamps: true
scrape_interval: 15s
scrape_timeout: 10s
metrics_path: /metrics
scheme: http
follow_redirects: true
static_configs:
  - targets:
      - localhost:9091