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 the PROMEX service for HAProxy. This document shows you how to do the following:

Set up the PROMEX service 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 managed collection with Managed Service for Prometheus. If you are using self-deployed collection, then see the HAProxy documentation for installation information.

These instructions are provided as an example and are expected to work in most Kubernetes environments. If you are having trouble installing an application or exporter due to restrictive security or organizational policies, then we recommend you consult open-source documentation for support.

For information about HAProxy, see HAProxy.

Prerequisites

To collect metrics from the PROMEX service for 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_promex version 2.4 or later.
For more information about available dashboards, see View dashboards.

HAProxy exposes Prometheus-format metrics only when it is built with the service enabled and an appropriate frontend is included in the configuration.

Most of the official Docker images for versions greater than or equal to 2.4 are built with this service enabled.

The following configuration example was built referencing HAProxy Enterprise documentation. It works with the community edition and can be modified to suit specific needs:

Modify the HAProxy configuration

Modify the 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 prometheus
+     mode http
+     bind *:8404
+     http-request use-service prometheus-exporter if { path /metrics }
    ...
---
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: haproxy
        image: haproxy:2.8
        ports:
+       - containerPort: 8404
+         name: prometheus
        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.

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.

To verify that the PROMEX service for HAProxy is emitting metrics on the expected endpoints,do the following:

Set up port forwarding by using the following command:

kubectl -n NAMESPACE_NAME port-forward POD_NAME 8404

Access the endpoint localhost:8404/metrics by using the browser or the curl utility in another terminal session.

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 values of the port and matchLabels fields match those of the HAProxy pods you want to monitor.

HAProxy exposes metrics from targets defined in the bind configuration option. This option requires a user to define the IP address and port to be listened on for scraping metrics.

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:

In the Google Cloud console, go to the Metrics explorer page:
Go to Metrics explorer

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
In the toolbar of the query-builder pane, select the button whose name is either MQL or PromQL.
Verify that PromQL is selected in the Language toggle. The language toggle is in the same toolbar that lets you format your query.

Enter 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:

In the Google Cloud console, go to the Dashboards page:
Go to Dashboards

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
Select the Dashboard List tab.
Choose the Integrations category.
Click the name of the dashboard, for example, HAProxy Prometheus Overview.

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

In the Google Cloud console, go to the Integrations page:
Go to Integrations

If you use the search bar to find this page, then select the result whose subheading is Monitoring.
Click the Kubernetes Engine deployment-platform filter.
Locate the HAProxy integration and click View Details.
Select the Dashboards tab.

Troubleshooting

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