HAProxy Now Exposes a Prometheus Metrics Endpoint

blog20190412-01.sh

sudo apt update
sudo apt install -y git ca-certificates gcc libc6-dev liblua5.3-dev libpcre3-dev libssl-dev libsystemd-dev make wget zlib1g-dev
git clone https://github.com/haproxy/haproxy.git
cd haproxy
make TARGET=linux-glibc USE_LUA=1 USE_OPENSSL=1 USE_PCRE=1 USE_ZLIB=1 USE_SYSTEMD=1 USE_PROMEX=1
sudo make install-bin

blog20190412-02.sh

sudo systemctl stop haproxy
sudo cp /usr/local/sbin/haproxy /usr/sbin/haproxy
sudo systemctl start haproxy

blog20190412-03.sh

haproxy -vv

Built with the Prometheus exporter as a service

blog20190412-04.cfg

frontend stats
   bind *:8404
   option http-use-htx
   http-request use-service prometheus-exporter if { path /metrics }
   stats enable
   stats uri /stats
   stats refresh 10s

blog20190412-05.yml

- job_name: 'haproxy'
  static_configs:
  - targets: ['localhost:8404']

blog20190412-06.sh

haproxy_frontend_http_requests_rate_current

blog20190412-07.sh

sum(haproxy_frontend_http_requests_rate_current{proxy="fe_main",job="haproxy"})

blog20190412-08.yml

rule_files:
  - 'alerts.yml'

blog20190412-09.yml

alerting:
  alertmanagers:
  - static_configs:
    - targets:
      - localhost:9093

blog20190412-10.yml

groups:
- name: be_servers_alert
  rules:
  - alert: be_servers_no_backends
    expr: haproxy_backend_active_servers{proxy="be_servers"} < 1
    for: 15s
    labels:
      severity: page      
    annotations:
      summary: HAProxy reports all servers are unhealthy for be_app.

blog20190412-11.yml

global:
  resolve_timeout: 5m
  smtp_from: 'alertmanager@example.com'
  smtp_smarthost: example.com:587
  smtp_auth_username: 'username'
  smtp_auth_password: 'password'

route:
  group_by: ['alertname']
  group_wait: 10s
  group_interval: 10s
  repeat_interval: 1h
  receiver: 'email'

blog20190412-12.yml

- alert: fe_main_rate_double
  expr: haproxy_frontend_http_requests_rate_current{proxy="fe_main"} > avg_over_time(haproxy_frontend_http_requests_rate_current{proxy="fe_main"}[24h])*2
  for: 15s
  labels:
    severity: page
  annotations:
    summary: HAProxy frontend request rate doubled for fe_main