docs: export metrics

docs/v0.5/en/user-guide/operations/configuration.md

@@ -451,6 +451,42 @@ append_stdout = true
 
 How to use distributed tracing, please reference [Tracing](./tracing.md)
 
+### Export metrics options
+
+`frontend`, `metasrv`, `datanode` and `standalone` support collecting metrics generated by themselves and sending the collected metrics to [Prometheus RemoteWrite protocol](https://prometheus.io/docs/concepts/remote_write_spec/) compatible receiver, such as sending to `greptimedb` itself. **Note: Export metrics has nothing to do with using Prometheus to scape metrics generated by `greptimedb`. Export metrics is only used as a way for `greptimedb` to export the metrics generated by itself.** Users can configure related export parameters through the `[export_metrics]` section.
+
+There are two ways to export metrics data:
+1. `remote_write` method: All components can be exported using this method. The user specifies a URL that supports the Prometheus RemoteWrite protocol through the relevant configuration under `[export_metrics.remote_write]`, and sends the metrics to the receiver through the URL.
+2. `self_import` method: Only `frontend` and `standalone` support exporting metrics using `self_import` method. Choosing the `self_import` method means that the user specifies that the collected metrics will be sent back to `greptimedb` itself. Users can export metrics by specifying the database name to which the metrics is exported through the relevant configuration under `[export_metrics.self_import]`.
+
+A configuration file exported using `remote_write` method:
+
+```toml
+[export_metrics]
+# Whether to enable export_metrics
+enable=true
+# Export time interval
+write_interval = "30s"
+[export_metrics.remote_write]
+# URL specified by Prometheus RemoteWrite protocol
+url = "http://127.0.0.1:4000/v1/prometheus/write?db=information_schema"
+# Some optional HTTP parameters, such as authentication information
+headers = { Authorization = "Basic Z3JlcHRpbWVfdXNlcjpncmVwdGltZV9wd2Q=" }
+```
+
+A configuration file exported using `self_import`:
+
+```toml
+[export_metrics]
+# Whether to enable export_metrics
+enable=true
+# Export time interval
+write_interval = "30s"
+[export_metrics.self_import]
+#Select the imported database name
+db = "information_schema"
+```
+
 ## Environment variable
 
 Every item in the configuration file can be mapped into environment variables. For example, if we want to set the configuration item `max_inflight_tasks` of datanode by environment variable:

docs/v0.5/zh/user-guide/operations/configuration.md

@@ -450,6 +450,43 @@ append_stdout = true
 
 如何使用分布式追踪，请参考 [Tracing](./tracing.md)
 
+### Export metrics 选项
+
+`frontend`、`metasrv`、`datanode` 和 `standalone` 支持收集自身产生的 metrics 数据，并将采集到的 metrics 数据发送到[Prometheus RemoteWrite 协议](https://prometheus.io/docs/concepts/remote_write_spec/)兼容的接收端，比如发送到 `greptimedb` 自身。**注意：该功能和使用 Prometheus 收集 `greptimedb` 产生的 metrics 没有关系，该功能仅作为 `greptimedb` 导出自身产生 metrics 的一种方式。** 用户可以通过 `[export_metrics]` 部分配置相关导出参数。
+
+总共有两种方式用于导出 metrics 数据：
+1. `remote_write` 方式：所有组件均可使用该方式导出。用户通过 `[export_metrics.remote_write]` 下的相关配置，指定一个支持 Prometheus RemoteWrite 协议的 URL，将产生的数据通过 URL 发送到接收端。
+2. `self_import` 方式：只有 `frontend`、`standalone` 支持使用 `self_import` 方式导出数据。选择 `self_import` 方式意味着用户指定了将收集到的 metrics 数据又送回到  `greptimedb` 自身。用户通过 `[export_metrics.self_import]` 下的相关配置，指定数据导出到的数据库库名，即可将数据导出到自身。
+
+一份使用 `remote_write` 方式导出的配置文件：
+
+```toml
+[export_metrics]
+# 是否启用 export_metrics
+enable = true
+# 导出时间间隔
+write_interval = "30s"
+[export_metrics.remote_write]
+# Prometheus RemoteWrite 协议规定的 URL
+url = "http://127.0.0.1:4000/v1/prometheus/write?db=information_schema"
+# 一些可选的 HTTP 参数，如鉴权信息
+headers = { Authorization = "Basic Z3JlcHRpbWVfdXNlcjpncmVwdGltZV9wd2Q=" }
+```
+
+
+一份使用 `self_import` 方式导出的配置文件：
+
+```toml
+[export_metrics]
+# 是否启用 export_metrics
+enable = true
+# 导出时间间隔
+write_interval = "30s"
+[export_metrics.self_import]
+# 选择导入的数据库库名
+db = "information_schema"
+```
+
 ## 环境变量配置
 
 配置文件中的每一项都可以映射到环境变量。例如，如果我们想通过环境变量设置 datanode 的配置项 `data_home`：