HashiCorp Consul

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 Consul exporter. This document shows you how to do the following:

Set up the Consul exporter 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.

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 Consul 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, we recommend you consult open-source documentation for support.

For information about Consul, see Consul.

Prerequisites

To collect metrics from the Consul exporter 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 Consul integration, you must use consul version 1.13.3 or later.
For more information about available dashboards, see View dashboards.

Consul exposes Prometheus-format metrics when the telemetry configuration options prometheus_retention_time and disable_hostname are set. These options can be set by mounting a configmap at /consul/config/metrics.hcl. HashiCorp recommends using a retention time twice that of the collection interval.

Modify the Consul configuration

Modify the Consul 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.

kind: StatefulSet
metadata:
  name: consul
spec:
  serviceName: consul
  selector:
    matchLabels:
+     app.kubernetes.io/name: consul
  template:
    metadata:
      labels:
+       app.kubernetes.io/name: consul
    spec:
      containers:
      - name: consul
        image: hashicorp/consul:1.16.0
        ports:
        - containerPort: 8500
          name: consul
          protocol: TCP
+       volumeMounts:
+       - mountPath: /consul/config/metrics.hcl
+         subPath: metrics.hcl
+         name: consul-telemetry
+     volumes:
+     - name: consul-telemetry
+       configMap:
+         name: consul-telemetry
+         items:
+         - key: metrics.hcl
+           path: metrics.hcl

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 determine if Consul is exposing metrics, run the following command:

  kubectl exec -n NAMESPACE_NAME POD_NAME -- curl -sS localhost:8500/v1/agent/metrics?format=prometheus

Define a PodMonitoring resource

For target discovery, the Managed Service for Prometheus Operator requires a PodMonitoring resource that corresponds to the Consul 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: consul
  labels:
    app.kubernetes.io/name: consul
    app.kubernetes.io/part-of: google-cloud-managed-prometheus
spec:
  endpoints:
  - port: 8500
    scheme: http
    interval: 30s
    path: /v1/agent/metrics
    params:
      format:
      - prometheus
  selector:
    matchLabels:
      app.kubernetes.io/name: consul

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.

Verify the configuration

You can use Metrics Explorer to verify that you correctly configured the Consul 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 navigation panel of the Google Cloud console, select Monitoring, and then select Metrics explorer:
Go to Metrics explorer
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="consul", cluster="CLUSTER_NAME", namespace="NAMESPACE_NAME"}

View dashboards

The Cloud Monitoring integration includes the Consul 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 navigation panel of the Google Cloud console, select Monitoring, and then select Dashboards:
Go to Dashboards
Select the Dashboard List tab.
Choose the Integrations category.
Click the name of the dashboard, for example, Consul Prometheus Overview.

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

In the navigation panel of the Google Cloud console, select Monitoring, and then select Integrations:
Go to Integrations
Click the Kubernetes Engine deployment-platform filter.
Locate the HashiCorp Consul 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.