A great starting place for an ec2 node exporter which binds metadata and tags.

ec2_sd_config

- job_name: service-ec2
  scrape_interval: 5s
  scrape_timeout: 5s
  metrics_path: /metrics
  scheme: http
  ec2_sd_configs:
  - region: us-east-1
    refresh_interval: 1m
    port: 9100
  relabel_configs:
  - source_labels: [__meta_ec2_tag_prometheus_io_scrape]
    separator: ;
    regex: "true"
    replacement: $1
    action: keep
  - separator: ;
    regex: __meta_ec2_tag_(.+)
    replacement: $1
    action: labelmap
  - source_labels: [__meta_ec2_instance_id]
    separator: ;
    regex: (.*)
    target_label: ec2_instance_id
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_availability_zone]
    separator: ;
    regex: (.*)
    target_label: ec2_availability_zone
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_instance_id]
    separator: ;
    regex: (.*)
    target_label: ec2_instance_id
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_instance_type]
    separator: ;
    regex: (.*)
    target_label: ec2_instance_type
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_instance_state]
    separator: ;
    regex: (.*)
    target_label: ec2_instance_state
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_vpc_id]
    separator: ;
    regex: (.*)
    target_label: ec2_vpc_id
    replacement: $1
    action: replace
  - source_labels: [__meta_ec2_subnet_id]
    separator: ;
    regex: (.*)
    target_label: ec2_subnet_id
    replacement: $1
    action: replace