HAProxy

This document describes how to configure your Google Kubernetes Engine deployment so that you can use Google Cloud Managed Service for Prometheus to collect metrics from HAProxy. This document shows you how to do the following:

  • Set up the exporter for HAProxy to report metrics.
  • Configure a PodMonitoring resource for Managed Service for Prometheus to collect the exported metrics.
  • Access a dashboard in Cloud Monitoring to view the metrics.
  • Configure alerting rules to monitor the metrics.

These instructions apply only if you are using using managed collection with Managed Service for Prometheus. If instead you are using self-deployed collection, then see the source repository for the HAProxy exporter for installation information.

For information about HAProxy, see HAProxy.

Prerequisites

To collect metrics from HAProxy by using Managed Service for Prometheus and managed collection, your deployment must meet the following requirements:

  • Your cluster must be running Google Kubernetes Engine version 1.21.4-gke.300 or later.
  • You must be running Managed Service for Prometheus with managed collection enabled. For more information, see Get started with managed collection.

  • To use dashboards available in Cloud Monitoring for the HAProxy integration, you must use haproxy_exporter version v0.13.0 or later.

    For more information about available dashboards, see View dashboards.

Install the HAProxy exporter

We recommend that you install the HAProxy exporter, haproxy_exporter, as a sidecar to your HAProxy workload. For information about using sidecars, see Extended applications on Kubernetes with multi-container pods.

To install haproxy_exporter as a sidecar to HAProxy, modify your HAProxy configuration as shown in the following example:

# Copyright 2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

apiVersion: v1
kind: ConfigMap
metadata:
  name: haproxy
data:
  haproxy.cfg: |
+   frontend stats
+     mode http
+     bind *:8404
+     stats enable
+     stats uri /stats
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: haproxy
spec:
  selector:
    matchLabels:
+     app.kubernetes.io/name: haproxy
  template:
    metadata:
      labels:
+       app.kubernetes.io/name: haproxy
    spec:
      containers:
+     - name: exporter
+       image: quay.io/prometheus/haproxy-exporter:v0.13.0
+       args:
+       - --haproxy.scrape-uri=http://localhost:8404/stats?stats;csv
+       ports:
+       - containerPort: 9101
+         name: prometheus
      - name: haproxy
        image: haproxy:2.3
        ports:
+       - containerPort: 8404
+         name: stats
        volumeMounts:
        - mountPath: /usr/local/etc/haproxy/haproxy.cfg
          subPath: haproxy.cfg
          name: haproxy
      volumes:
      - name: haproxy
        configMap:
          name: haproxy
          items:
          - key: haproxy.cfg
            path: haproxy.cfg

You must add any lines preceded by the + symbol to your configuration.

The recommended changes in haproxy.cfg defines a frontend with the "stats enable" directive and enables the HAProxy stats page. This frontend can be scraped by haproxy_exporter. For more information, see Exploring the HAProxy Stats page.

To apply configuration changes from a local file, run the following command: 

kubectl apply -n NAMESPACE_NAME -f FILE_NAME

You can also use Terraform to manage your configurations.

Define a PodMonitoring resource

For target discovery, the Managed Service for Prometheus Operator requires a PodMonitoring resource that corresponds to the HAProxy exporter in the same namespace.

You can use the following PodMonitoring configuration:

# Copyright 2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

apiVersion: monitoring.googleapis.com/v1
kind: PodMonitoring
metadata:
  name: haproxy
  labels:
    app.kubernetes.io/name: haproxy
    app.kubernetes.io/part-of: google-cloud-managed-prometheus
spec:
  endpoints:
  - port: prometheus
    scheme: http
    interval: 30s
    path: /metrics
  selector:
    matchLabels:
      app.kubernetes.io/name: haproxy

Ensure that the label selectors and the port match the selectors and port used in Install the HAProxy exporter.

To apply configuration changes from a local file, run the following command: 

kubectl apply -n NAMESPACE_NAME -f FILE_NAME

You can also use Terraform to manage your configurations.

Define rules and alerts

You can use the following Rules configuration to define alerts on your HAProxy metrics:

# Copyright 2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

apiVersion: monitoring.googleapis.com/v1
kind: Rules
metadata:
  name: haproxy-rules
  labels:
    app.kubernetes.io/component: rules
    app.kubernetes.io/name: haproxy-rules
    app.kubernetes.io/part-of: google-cloud-managed-prometheus
spec:
  groups:
  - name: haproxy
    interval: 30s
    rules:
    - alert: HAProxyDown
      annotations:
        description: |-
          HAProxy instance is down
            VALUE = {{ $value }}
            LABELS: {{ $labels }}
        summary: HAProxy down (instance {{ $labels.instance }})
      expr: haproxy_server_up{job="haproxy"} == 0
      for: 5m
      labels:
        severity: critical
    - alert: HAProxyTooManyConnections
      annotations:
        description: |-
          HAProxy instance has too many connections
            VALUE = {{ $value }}
            LABELS: {{ $labels }}
        summary: HAProxy too many connections (instance {{ $labels.instance }})
      expr: haproxy_frontend_current_sessions{job="haproxy"} / haproxy_frontend_limit_sessions{job="haproxy"} * 100 > 90
      for: 5m
      labels:
        severity: warning

To apply configuration changes from a local file, run the following command: 

kubectl apply -n NAMESPACE_NAME -f FILE_NAME

You can also use Terraform to manage your configurations.

For more information about applying rules to your cluster, see Managed rule evaluation and alerting.

Verify the configuration

You can use Metrics Explorer to verify that you correctly configured the HAProxy exporter. It might take one or two minutes for Cloud Monitoring to ingest your metrics.

To verify the metrics are ingested, do the following:

  1. In the Google Cloud console, select Monitoring or click the following button:
    Go to Monitoring
  2. In the navigation pane, select   Metrics Explorer.
  3. Select the PromQL tab, and run the following query:
    up{job="haproxy", cluster="CLUSTER_NAME", namespace="NAMESPACE_NAME"}

View dashboards

The Cloud Monitoring integration includes the HAProxy Prometheus Overview dashboard. Dashboards are automatically installed when you configure the integration. You can also view static previews of dashboards without installing the integration.

To view an installed dashboard, do the following:

  1. In the Google Cloud console, select Monitoring or click the following button:
    Go to Monitoring
  2. In the navigation pane, select  Dashboards.
  3. Select the Dashboard List tab.
  4. Choose the Integrations category.
  5. Click the name of the dashboard, for example, HAProxy Prometheus Overview.

To view a static preview of the dashboard, do the following:

  1. In the Google Cloud console, select Monitoring or click the following button:
    Go to Monitoring
  2. In the navigation pane, select  Integrations.
  3. Click the Kubernetes Engine deployment-platform filter.
  4. Locate the HAProxy integration and click View Details.
  5. Select the Dashboards tab.

Troubleshooting

For information about troubleshooting metric-ingestion problems, see Problems with collection from exporters in Troubleshooting ingestion-side problems.