prometheus学习系列六： Prometheus relabel配置

relabel_config

重新标记是一个功能强大的工具，可以在目标的标签集被抓取之前重写它，每个采集配置可以配置多个重写标签设置，并按照配置的顺序来应用于每个目标的标签集。

目标重新标签之后，以__开头的标签将从标签集中删除的。

如果使用只需要临时的存储临时标签值的，可以使用_tmp作为前缀标识。

relabel的action类型

• replace: 对标签和标签值进行替换。
• keep: 满足特定条件的实例进行采集，其他的不采集。
• drop： 满足特定条件的实例不采集，其他的采集。
• hashmod： 这个我也没看懂啥意思，囧。
• labelmap： 这个我也没看懂啥意思，囧。
• labeldrop： 对抓取的实例特定标签进行删除。
• labelkeep：  对抓取的实例特定标签进行保留，其他标签删除。

常用action的测试

在测试前，同步下配置文件如下。

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files: 
      - "/usr/local/prometheus/prometheus/conf/node*.yml"


[root@node00 prometheus]# cat conf/node-dis.yml 
- targets: 
  - "192.168.100.10:20001"
  labels: 
    __hostname__: node00
    __businees_line__: "line_a"
    __region_id__: "cn-beijing"
    __availability_zone__: "a"
- targets: 
  - "192.168.100.11:20001"
  labels: 
    __hostname__: node01
    __businees_line__: "line_a"
    __region_id__: "cn-beijing"
    __availability_zone__: "a"
- targets: 
  - "192.168.100.12:20001"
  labels: 
    __hostname__: node02
    __businees_line__: "line_c"
    __region_id__: "cn-beijing"
    __availability_zone__: "b"

此时如果查看target信息，如下图。

因为我们的label都是以__开头的，目标重新标签之后，以__开头的标签将从标签集中删除的。

一个简单的relabel设置

将labels中的__hostname__替换为node_name。

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files:
      - "/usr/local/prometheus/prometheus/conf/node*.yml"
    relabel_configs:
    - source_labels:
      - "__hostname__"
      regex: "(.*)"
      target_label: "nodename"
      action: replace
      replacement: "$1"

重启服务查看target信息如下图：

说下上面的配置： source_labels指定我们我们需要处理的源标签， target_labels指定了我们要replace后的标签名字， action指定relabel动作，这里使用replace替换动作。 regex去匹配源标签（__hostname__）的值，"(.*)"代表__hostname__这个标签是什么值都匹配的，然后replacement指定的替换后的标签（target_label）对应的数值。采用正则引用方式获取的。

这里修改下上面的正则表达式为 ‘’regex: "(node00)"'的时候可以看到如下图。

keep

修改配置文件

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files:
      - "/usr/local/prometheus/prometheus/conf/node*.yml"

target如下图

修改配置文件如下

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files: 
      - "/usr/local/prometheus/prometheus/conf/node*.yml"
    relabel_configs:
    - source_labels:
      - "__hostname__"
      regex: "node00"
      action: keep

target如下图

action为keep，只要source_labels的值匹配regex（node00）的实例才能会被采集。 其他的实例不会被采集。

drop

在上面的基础上，修改action为drop。

target如下图

action为drop，其实和keep是相似的， 不过是相反的， 只要source_labels的值匹配regex（node00）的实例不会被采集。 其他的实例会被采集。

replace

我们的基础信息里面有__region_id__和__availability_zone__，但是我想融合2个字段在一起，可以通过replace来实现。

修改配置如下

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files:
      - "/usr/local/prometheus/prometheus/conf/node*.yml"
    relabel_configs:
    - source_labels:
      - "__region_id__"
      - "__availability_zone__"
      separator: "-"
      regex: "(.*)"
      target_label: "region_zone"
      action: replace
      replacement: "$1"

target如下图：

labelkeep

配置文件如下

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files:
      - "/usr/local/prometheus/prometheus/conf/node*.yml"
    relabel_configs:
    - source_labels:
      - "__hostname__"
      regex: "(.*)"
      target_label: "nodename"
      action: replace
      replacement: "$1"
    - source_labels:
      - "__businees_line__"
      regex: "(.*)"
      target_label: "businees_line"
      action: replace
      replacement: "$1"
    - source_labels:
      - "__datacenter__"
      regex: "(.*)"
      target_label: "datacenter"
      action: replace
      replacement: "$1"

target如下图

 修改配置文件如下

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']
  - job_name: "node"
    file_sd_configs:
    - refresh_interval: 1m
      files:
      - "/usr/local/prometheus/prometheus/conf/node*.yml"
    relabel_configs:
    - source_labels:
      - "__hostname__"
      regex: "(.*)"
      target_label: "nodename"
      action: replace
      replacement: "$1"
    - source_labels:
      - "__businees_line__"
      regex: "(.*)"
      target_label: "businees_line"
      action: replace
      replacement: "$1"
    - source_labels:
      - "__datacenter__"
      regex: "(.*)"
      target_label: "datacenter"
      action: replace
      replacement: "$1"
    - regex: "(nodename|datacenter)"
      action: labeldrop

target如下图