{D4} - Prometheus的Relabeling机制

http_requests_time{code="200", path="/api/v1/query", instance="10.0.0.2"}

global:
...

rule_files:
...

scrape_configs:
  - job_name: sample_job_1
    kubernetes_sd_configs:
    - ...
    relabel_configs:           # <-
    - source_labels: [...]
       ...
    - source_labels: [...]
      ...
    metric_relabel_configs:    # <-
    - source_labels: [...]
      ...
    - source_labels: [...]
      ...
  - job_name: sample_job_2
    static_configs:
    - targets: [...]
    metric_relabel_configs:    # <-
    - source_labels: [...]
      ...

alerting:
  alert_relabel_configs:       # <-
    [ - <relabel_config> ... ]
  alertmanagers:
    [ - <alertmanager_config> ... ]

remote_write:
- url: ...
  write_relabel_configs:       # <-
  - source_labels: [...]
    ...
  - source_labels: [...]
    ...

# metric
my_counter_total{server="web01",project="dadou"} 192  1644075044000
my_counter_total{server="cache01",project="dadou"} 147  1644075044000

# relabel_config:
source_labels: [project, server]
separator: "@"

# after relabeling:
dadou@web01
dadou@cache01

# relabel_config:
source_labels: [project, server]
separator: "@"
regex: "(.*)@(.*)"
replacement: "${2}+${1}"

# after relabeling:
web01+dadou
cache01+dadou

# relabel_config:
source_labels: [project, server]
separator: "@"
regex: "(.*)@(.*)"
replacement: "${2}/${1}"
target_label: "my_new_label"
action: "replace"

# after relabeling:
{my_new_label="web01/dadou"}
{my_new_label="cache01/dadou"}

# relabel_config 1:dadou
source_labels: [project, server]
separator: "@"
regex: "dadou@web"
action: "drop"

# relabel_config 2:
source_labels: [project, server]
separator: "@"
regex: "dadou@(.*)"
action: keep

# relabel_config 3:
source_labels: [__name__]
regex: "my_custom_counter_total|my_custom_counter_sum|my_custom_gauge"
action: keep

# relabel_config 4:
source_labels: [__meta_kubernetes_namespace]
regex: "testing|staging"
action: drop

# relabel_config 1:
regex: "project"
action: labeldrop

# relabel_config 2:
regex: "project|server|shard"
action: labelkeep

# 设置一个固定的标签值
# relabel_config 1:
action: replace
replacement: production
target_label: env

# 替换标签的值
# relabel_config 2:
action: replace
source_labels: [__meta_kubernetes_pod_name,__meta_kubernetes_pod_container_port_number]
separator: ":"
target_label: address

# metric
my_custom_metric{name="node",val="42"} 100

# relabel_config
action: hashmod
source_labels: [name, val]
separator: "-"
modulus: 8
target_label: __tmp_hashmod

# 连接的结果是字符串“node-42”，字符串模数 8 的 MD5 是5
$ python3
>>> import hashlib
>>> m = hashlib.md5(b"node-42")
>>> int(m.hexdigest(), 16) % 8
5
# 所以最终{__tmp=5}会被附加到指标的标签集中。
#
# 这最常用于在一组Prometheus实例中对多个目标进行分片。
# 以下规则可用于在8个Prometheus实例之间分配负载，
# 每个实例负责抓取最终在`[0, 7]` 范围内
# 产生特定值的目标子集，并忽略所有其他实例。

# relabel_config
action: keep
source_labels: [__tmp_hashmod]
regex: 5

    __meta_kubernetes_node_name: The name of the node object.
    __meta_kubernetes_node_provider_id: The cloud provider's name for the node object.
    __meta_kubernetes_node_address_<address_type>: The first address for each node address type, if it exists.
…
    __meta_kubernetes_namespace: The namespace of the service object.
    __meta_kubernetes_service_external_name: The DNS name of the service. (Applies to services of type ExternalName)
    __meta_kubernetes_service_name: The name of the service object.
    __meta_kubernetes_service_port_name: Name of the service port for the target.
…
    __meta_kubernetes_pod_name: The name of the pod object.
    __meta_kubernetes_pod_ip: The pod IP of the pod object.
    __meta_kubernetes_pod_container_init: true if the container is an InitContainer
    __meta_kubernetes_pod_container_name: Name of the container the target address points to.

action: labelmap
regex: "__meta_kubernetes_(.*)"
replacement: "k8s_${1}"