Use Your Load Balancer to Monitor Application Health

blog20220304-01.sh

$ haproxy -vv | grep "Prometheus exporter"

Built with the Prometheus exporter as a service

blog20220304-02.cfg

frontend metrics
  bind :8404
  stats enable
  stats uri /
  stats refresh 5s
  http-request use-service prometheus-exporter if { path /metrics }

blog20220304-03.sh

$ sudo systemctl restart haproxy

blog20220304-04.yml

global:
  scrape_interval: 5s
  evaluation_interval: 5s

scrape_configs:
  - job_name: 'haproxy'
    static_configs:
      - targets: ['127.0.0.1:8404']

blog20220304-05.sh

$ sudo systemctl restart prometheus

blog20220304-06.sh

haproxy_backend_agg_server_check_status{proxy="webservers", state="UP"}

blog20220304-07.sh

rate(haproxy_server_http_responses_total{proxy="webservers",code=~"2xx|4xx|5xx"}[30s])