Monitor Caddy and Consul integration with Prometheus and Grafana dashboards

Update system packages

Start by updating your package manager to ensure you get the latest versions of all components.

sudo apt update && sudo apt upgrade -y

sudo dnf update -y

Install Prometheus

Download and install Prometheus to collect metrics from Caddy and Consul. We'll create a dedicated user for security.

sudo useradd --no-create-home --shell /bin/false prometheus
sudo mkdir /etc/prometheus
sudo mkdir /var/lib/prometheus
sudo chown prometheus:prometheus /etc/prometheus
sudo chown prometheus:prometheus /var/lib/prometheus

cd /tmp
wget https://github.com/prometheus/prometheus/releases/download/v2.45.0/prometheus-2.45.0.linux-amd64.tar.gz
tar xvf prometheus-2.45.0.linux-amd64.tar.gz
sudo cp prometheus-2.45.0.linux-amd64/prometheus /usr/local/bin/
sudo cp prometheus-2.45.0.linux-amd64/promtool /usr/local/bin/
sudo chown prometheus:prometheus /usr/local/bin/prometheus
sudo chown prometheus:prometheus /usr/local/bin/promtool

Configure Prometheus for Caddy and Consul

Create the main Prometheus configuration file with scrape targets for both Caddy metrics and Consul endpoints.

global:
  scrape_interval: 15s
  evaluation_interval: 15s

rule_files:
  - "caddy_rules.yml"
  - "consul_rules.yml"

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

scrape_configs:
  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

  - job_name: 'caddy'
    static_configs:
      - targets: ['localhost:2019']
    metrics_path: '/metrics'
    scrape_interval: 30s

  - job_name: 'consul'
    static_configs:
      - targets: ['localhost:8500']
    metrics_path: '/v1/agent/metrics'
    params:
      format: ['prometheus']
    scrape_interval: 30s

  - job_name: 'consul-services'
    consul_sd_configs:
      - server: 'localhost:8500'
        services: []
    relabel_configs:
      - source_labels: [__meta_consul_service]
        target_label: service
      - source_labels: [__meta_consul_node]
        target_label: node

sudo chown prometheus:prometheus /etc/prometheus/prometheus.yml

Configure Caddy to expose metrics

Enable Caddy's built-in metrics endpoint by adding the admin API configuration to your Caddyfile.

{
  admin :2019
  servers {
    metrics
  }
}

example.com {
  reverse_proxy consul.service.consul:8080 {
    health_uri /health
    health_interval 10s
    health_timeout 5s
  }
  
  log {
    output file /var/log/caddy/access.log {
      roll_size 100mb
      roll_keep 5
    }
    format json
  }
}

sudo systemctl reload caddy

Enable Consul metrics

Configure Consul to expose Prometheus metrics through its HTTP API by updating the agent configuration.

{
  "telemetry": {
    "prometheus_retention_time": "30s",
    "disable_hostname": false
  },
  "ports": {
    "grpc": 8502
  },
  "connect": {
    "enabled": true
  }
}

sudo systemctl reload consul

Create alerting rules for Caddy

Define Prometheus alerting rules to monitor Caddy performance and availability issues.

groups:
- name: caddy.rules
  rules:
  - alert: CaddyDown
    expr: up{job="caddy"} == 0
    for: 1m
    labels:
      severity: critical
    annotations:
      summary: "Caddy server is down"
      description: "Caddy has been down for more than 1 minute"

  - alert: CaddyHighRequestLatency
    expr: histogram_quantile(0.95, rate(caddy_http_request_duration_seconds_bucket[5m])) > 0.5
    for: 2m
    labels:
      severity: warning
    annotations:
      summary: "High request latency on Caddy"
      description: "95th percentile latency is {{ $value }}s"

  - alert: CaddyHighErrorRate
    expr: rate(caddy_http_requests_total{status=~"5.."}[5m]) / rate(caddy_http_requests_total[5m]) > 0.05
    for: 2m
    labels:
      severity: critical
    annotations:
      summary: "High error rate on Caddy"
      description: "Error rate is {{ $value | humanizePercentage }}"

  - alert: CaddyUpstreamDown
    expr: caddy_reverse_proxy_upstreams_healthy == 0
    for: 1m
    labels:
      severity: critical
    annotations:
      summary: "Caddy upstream is down"
      description: "No healthy upstreams available for {{ $labels.upstream }}"

  - alert: CaddyHighMemoryUsage
    expr: process_resident_memory_bytes{job="caddy"} / 1024 / 1024 > 500
    for: 5m
    labels:
      severity: warning
    annotations:
      summary: "Caddy high memory usage"
      description: "Caddy memory usage is {{ $value }}MB"

Create alerting rules for Consul

Set up Consul-specific alerts for cluster health, service discovery issues, and performance problems.

groups:
- name: consul.rules
  rules:
  - alert: ConsulDown
    expr: up{job="consul"} == 0
    for: 1m
    labels:
      severity: critical
    annotations:
      summary: "Consul agent is down"
      description: "Consul agent has been down for more than 1 minute"

  - alert: ConsulLeaderMissing
    expr: consul_raft_leader == 0
    for: 1m
    labels:
      severity: critical
    annotations:
      summary: "Consul cluster has no leader"
      description: "Consul cluster is without a leader"

  - alert: ConsulHighMemoryUsage
    expr: consul_runtime_alloc_bytes / 1024 / 1024 > 1000
    for: 5m
    labels:
      severity: warning
    annotations:
      summary: "Consul high memory usage"
      description: "Consul memory usage is {{ $value }}MB"

  - alert: ConsulServiceUnhealthy
    expr: consul_health_service_query_count{status!="passing"} > 0
    for: 2m
    labels:
      severity: warning
    annotations:
      summary: "Consul service health check failing"
      description: "Service {{ $labels.service }} health check is failing"

  - alert: ConsulNodeUnhealthy
    expr: consul_health_node_query_count{status!="passing"} > 0
    for: 2m
    labels:
      severity: critical
    annotations:
      summary: "Consul node health check failing"
      description: "Node {{ $labels.node }} health check is failing"

  - alert: ConsulRaftLogGrowth
    expr: increase(consul_raft_commitIndex[1h]) > 10000
    for: 5m
    labels:
      severity: warning
    annotations:
      summary: "High Consul raft log growth"
      description: "Raft log has grown by {{ $value }} entries in the last hour"

Set correct permissions for Prometheus files

Ensure Prometheus can read all configuration files by setting appropriate ownership and permissions.

sudo chown prometheus:prometheus /etc/prometheus/caddy_rules.yml
sudo chown prometheus:prometheus /etc/prometheus/consul_rules.yml
sudo chmod 644 /etc/prometheus/*.yml

Create Prometheus systemd service

Set up Prometheus as a systemd service for automatic startup and management.

[Unit]
Description=Prometheus
Wants=network-online.target
After=network-online.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/usr/local/bin/prometheus \
    --config.file /etc/prometheus/prometheus.yml \
    --storage.tsdb.path /var/lib/prometheus/ \
    --web.console.templates=/etc/prometheus/consoles \
    --web.console.libraries=/etc/prometheus/console_libraries \
    --web.listen-address=0.0.0.0:9090 \
    --web.enable-lifecycle \
    --storage.tsdb.retention.time=30d

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now prometheus

Install Grafana

Add the Grafana repository and install it to create dashboards for monitoring data visualization.

sudo apt install -y software-properties-common wget
wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
echo "deb https://packages.grafana.com/oss/deb stable main" | sudo tee /etc/apt/sources.list.d/grafana.list
sudo apt update
sudo apt install -y grafana

sudo dnf install -y wget
sudo tee /etc/yum.repos.d/grafana.repo <

Configure Grafana data source

Create a Grafana configuration to automatically provision the Prometheus data source.

`apiVersion: 1

datasources:
  - name: Prometheus
    type: prometheus
    access: proxy
    url: http://localhost:9090
    isDefault: true
    editable: true`

Create Caddy dashboard configuration

Set up a comprehensive Grafana dashboard to monitor Caddy reverse proxy metrics and performance.

`{
  "dashboard": {
    "id": null,
    "title": "Caddy Reverse Proxy Monitoring",
    "tags": ["caddy", "proxy"],
    "timezone": "browser",
    "panels": [
      {
        "id": 1,
        "title": "HTTP Requests per Second",
        "type": "graph",
        "targets": [
          {
            "expr": "rate(caddy_http_requests_total[5m])",
            "legendFormat": "{{method}} {{host}}"
          }
        ],
        "yAxes": [
          {
            "label": "requests/sec"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 0,
          "y": 0
        }
      },
      {
        "id": 2,
        "title": "Response Time Percentiles",
        "type": "graph",
        "targets": [
          {
            "expr": "histogram_quantile(0.50, rate(caddy_http_request_duration_seconds_bucket[5m]))",
            "legendFormat": "50th percentile"
          },
          {
            "expr": "histogram_quantile(0.95, rate(caddy_http_request_duration_seconds_bucket[5m]))",
            "legendFormat": "95th percentile"
          },
          {
            "expr": "histogram_quantile(0.99, rate(caddy_http_request_duration_seconds_bucket[5m]))",
            "legendFormat": "99th percentile"
          }
        ],
        "yAxes": [
          {
            "label": "seconds"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 12,
          "y": 0
        }
      },
      {
        "id": 3,
        "title": "HTTP Status Codes",
        "type": "graph",
        "targets": [
          {
            "expr": "rate(caddy_http_requests_total{status=~\"2..\"}[5m])",
            "legendFormat": "2xx Success"
          },
          {
            "expr": "rate(caddy_http_requests_total{status=~\"4..\"}[5m])",
            "legendFormat": "4xx Client Error"
          },
          {
            "expr": "rate(caddy_http_requests_total{status=~\"5..\"}[5m])",
            "legendFormat": "5xx Server Error"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 0,
          "y": 8
        }
      },
      {
        "id": 4,
        "title": "Upstream Health Status",
        "type": "stat",
        "targets": [
          {
            "expr": "caddy_reverse_proxy_upstreams_healthy",
            "legendFormat": "{{upstream}}"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 12,
          "y": 8
        }
      }
    ],
    "time": {
      "from": "now-1h",
      "to": "now"
    },
    "refresh": "30s"
  }
}`

Create Consul dashboard configuration

Build a Grafana dashboard specifically for monitoring Consul cluster health and service discovery metrics.

`{
  "dashboard": {
    "id": null,
    "title": "Consul Cluster Monitoring",
    "tags": ["consul", "service-discovery"],
    "timezone": "browser",
    "panels": [
      {
        "id": 1,
        "title": "Consul Nodes Status",
        "type": "stat",
        "targets": [
          {
            "expr": "consul_serf_lan_members",
            "legendFormat": "Active Nodes"
          }
        ],
        "gridPos": {
          "h": 4,
          "w": 6,
          "x": 0,
          "y": 0
        }
      },
      {
        "id": 2,
        "title": "Raft Leader Status",
        "type": "stat",
        "targets": [
          {
            "expr": "consul_raft_leader",
            "legendFormat": "Has Leader"
          }
        ],
        "gridPos": {
          "h": 4,
          "w": 6,
          "x": 6,
          "y": 0
        }
      },
      {
        "id": 3,
        "title": "Service Health Checks",
        "type": "graph",
        "targets": [
          {
            "expr": "consul_health_service_query_count{status=\"passing\"}",
            "legendFormat": "Passing"
          },
          {
            "expr": "consul_health_service_query_count{status=\"warning\"}",
            "legendFormat": "Warning"
          },
          {
            "expr": "consul_health_service_query_count{status=\"critical\"}",
            "legendFormat": "Critical"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 0,
          "y": 4
        }
      },
      {
        "id": 4,
        "title": "Memory Usage",
        "type": "graph",
        "targets": [
          {
            "expr": "consul_runtime_alloc_bytes / 1024 / 1024",
            "legendFormat": "Allocated Memory (MB)"
          },
          {
            "expr": "consul_runtime_sys_bytes / 1024 / 1024",
            "legendFormat": "System Memory (MB)"
          }
        ],
        "yAxes": [
          {
            "label": "MB"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 12,
          "x": 12,
          "y": 4
        }
      },
      {
        "id": 5,
        "title": "Raft Transactions",
        "type": "graph",
        "targets": [
          {
            "expr": "rate(consul_raft_apply[5m])",
            "legendFormat": "Apply Rate"
          },
          {
            "expr": "consul_raft_commitIndex",
            "legendFormat": "Commit Index"
          }
        ],
        "gridPos": {
          "h": 8,
          "w": 24,
          "x": 0,
          "y": 12
        }
      }
    ],
    "time": {
      "from": "now-1h",
      "to": "now"
    },
    "refresh": "30s"
  }
}`

Create dashboard provisioning configuration

Set up Grafana to automatically load the dashboard configurations on startup.

`apiVersion: 1

providers:
  - name: 'default'
    orgId: 1
    folder: ''
    type: file
    disableDeletion: false
    updateIntervalSeconds: 10
    allowUiUpdates: true
    options:
      path: /etc/grafana/provisioning/dashboards`

Install and configure Alertmanager

Set up Alertmanager to handle alerts from Prometheus and send notifications for critical issues.

`cd /tmp
wget https://github.com/prometheus/alertmanager/releases/download/v0.26.0/alertmanager-0.26.0.linux-amd64.tar.gz
tar xvf alertmanager-0.26.0.linux-amd64.tar.gz
sudo cp alertmanager-0.26.0.linux-amd64/alertmanager /usr/local/bin/
sudo cp alertmanager-0.26.0.linux-amd64/amtool /usr/local/bin/
sudo useradd --no-create-home --shell /bin/false alertmanager
sudo mkdir /etc/alertmanager
sudo mkdir /var/lib/alertmanager
sudo chown alertmanager:alertmanager /etc/alertmanager
sudo chown alertmanager:alertmanager /var/lib/alertmanager
sudo chown alertmanager:alertmanager /usr/local/bin/alertmanager
sudo chown alertmanager:alertmanager /usr/local/bin/amtool`

Configure Alertmanager notifications

Set up Alertmanager to send email notifications for critical alerts from both Caddy and Consul monitoring.

`global:
  smtp_smarthost: 'smtp.example.com:587'
  smtp_from: 'alerts@example.com'
  smtp_auth_username: 'alerts@example.com'
  smtp_auth_password: 'your_smtp_password'

route:
  group_by: ['alertname']
  group_wait: 10s
  group_interval: 10s
  repeat_interval: 1h
  receiver: 'web.hook'

receivers:
- name: 'web.hook'
  email_configs:
  - to: 'admin@example.com'
    subject: '[ALERT] {{ .GroupLabels.alertname }}'
    body: |
      {{ range .Alerts }}
      Alert: {{ .Annotations.summary }}
      Descript`