Introduction

Cloud Monitoring is a powerful tool for gaining insights into the performance and health of your applications and infrastructure. While it provides a wealth of default metrics, truly effective monitoring often requires going beyond the basics. This post will guide you through creating custom dashboards and setting up proactive alerting policies focused on your key Service Level Indicators (SLIs).

Understanding Service Level Indicators (SLIs)

Before diving into the technical details, it’s crucial to define what you want to monitor. SLIs are quantifiable metrics that represent the performance of your services. Common examples include:

  • Latency: The time it takes to respond to a request.
  • Error Rate: The percentage of requests that result in errors.
  • Throughput: The number of requests processed per unit of time.
  • Availability: The percentage of time a service is operational.

Identifying your critical SLIs is the first step towards building effective monitoring.

Building Custom Dashboards

Cloud Monitoring’s dashboards allow you to visualize your SLIs and gain a comprehensive view of your system’s health. Here’s how to create powerful custom dashboards:

1. Accessing the Dashboards Section

Navigate to the Cloud Monitoring section in the Google Cloud Console. In the left-hand navigation menu, select “Dashboards.”

2. Creating a New Dashboard

Click the “+ CREATE DASHBOARD” button. Give your dashboard a descriptive name.

3. Adding Charts

Dashboards are built using charts. To add a chart, click “Add Chart.” You’ll then be presented with a configuration panel.

4. Configuring a Chart

The chart configuration panel allows you to define the data you want to visualize.

  • Resource Type: Select the Google Cloud resource you want to monitor (e.g., Compute Engine instance, Cloud Functions function, Cloud SQL instance).
  • Metric: Choose the metric you want to display. Cloud Monitoring provides a vast array of pre-defined metrics. You can also create custom metrics (more on that later).
  • Filter: Use filters to narrow down the data displayed in the chart. For example, you might filter by zone, instance name, or service name.
  • Aggregation: Choose an aggregation method (e.g., average, sum, percentile) to combine data points over time.
  • Chart Type: Select the appropriate chart type for your data (e.g., line chart, bar chart, heatmap). Line charts are often suitable for displaying time-series data like latency or throughput.
  • Title and Axis Labels: Give your chart a clear title and label the axes for easy understanding.

Example: Monitoring Average CPU Utilization of Compute Engine Instances

To monitor the average CPU utilization of your Compute Engine instances, you would:

  1. Select “Compute Engine Instance” as the resource type.
  2. Choose “CPU utilization” as the metric.
  3. Optionally, filter by zone or instance name.
  4. Set the aggregation to “Average.”
  5. Select “Line chart” as the chart type.

5. Creating Custom Metrics

Sometimes the default metrics aren’t enough. You might need to create custom metrics to track specific aspects of your application’s behavior. Cloud Monitoring supports several types of custom metrics, including:

  • Gauge: A snapshot of a value at a particular point in time.
  • Counter: A monotonically increasing value.
  • Distribution: A histogram of values.

You can create custom metrics using the Cloud Monitoring API or client libraries.

Example: Creating a Custom Metric for Request Latency

from google.cloud import monitoring_v3

def create_metric(project_id, metric_name, description):
    client = monitoring_v3.MetricServiceClient()
    project_name = f"projects/{project_id}"
    descriptor = monitoring_v3.MetricDescriptor()
    descriptor.type = f"custom.googleapis.com/{metric_name}"
    descriptor.metric_kind = monitoring_v3.enums.MetricDescriptor.MetricKind.GAUGE
    descriptor.value_type = monitoring_v3.enums.MetricDescriptor.ValueDescriptorType.DOUBLE
    descriptor.description = description

    try:
        descriptor = client.create_metric_descriptor(project_name, descriptor)
        print("Created {}.".format(descriptor.name))
    except Exception as e:
        print(f"Error creating metric: {e}")

# Example Usage
project_id = "your-gcp-project-id"
metric_name = "request_latency"
description = "Latency of incoming requests in milliseconds"
create_metric(project_id, metric_name, description)

Once you’ve created a custom metric, you can report data to it using the Cloud Monitoring API. You’ll need to write code to collect the data from your application and send it to Cloud Monitoring.

Setting Up Alerting Policies

Dashboards are valuable for visualizing data, but alerting policies are essential for proactive monitoring. Alerting policies trigger notifications when your SLIs deviate from acceptable thresholds.

1. Accessing the Alerting Section

In the Cloud Monitoring section of the Google Cloud Console, select “Alerting” from the left-hand navigation menu.

2. Creating a New Alerting Policy

Click the “+ CREATE POLICY” button.

3. Configuring the Alerting Policy

The alerting policy configuration panel allows you to define the conditions that trigger an alert.

  • Metric: Select the metric you want to monitor. This should be one of your key SLIs.
  • Filter: Use filters to narrow down the scope of the alert.
  • Aggregation: Choose an aggregation method.
  • Condition: Define the condition that triggers the alert. Common conditions include “is above,” “is below,” and “is absent.” You’ll also need to specify a threshold value and a duration. For example, you might create an alert that triggers when latency is above 200ms for 5 minutes.
  • Notification Channels: Configure the notification channels to use when an alert is triggered. Supported channels include email, SMS, Slack, and PagerDuty.
  • Documentation: Add documentation to the alert to help responders understand the issue and how to resolve it.

Example: Alerting on High Error Rate

To create an alert that triggers when the error rate exceeds 5% for 1 minute, you would:

  1. Select the metric representing the error rate.
  2. Set the condition to “is above.”
  3. Set the threshold to “5%.”
  4. Set the duration to “1 minute.”
  5. Configure a notification channel (e.g., email).

4. Utilizing SLOs for Alerting

Service Level Objectives (SLOs) are targets for your SLIs. Cloud Monitoring allows you to create alerting policies directly based on SLO breaches. This provides a streamlined way to ensure you’re meeting your service level agreements. Create SLOs within the Cloud Monitoring interface and then use those SLOs when defining alerting policies.

Best Practices for Dashboards and Alerting

  • Focus on Key SLIs: Don’t overwhelm yourself with too many metrics. Prioritize the SLIs that are most critical to your business.
  • Use Clear and Concise Labels: Make sure your dashboards and alerts are easy to understand.
  • Set Realistic Thresholds: Avoid setting thresholds that are too sensitive, which can lead to alert fatigue.
  • Test Your Alerts: Regularly test your alerting policies to ensure they are working correctly.
  • Document Your Dashboards and Alerts: Provide clear documentation to help responders understand the purpose of each dashboard and alert.
  • Iterate and Improve: Continuously review and refine your dashboards and alerts as your application evolves.

Conclusion

By creating custom dashboards and setting up proactive alerting policies, you can gain a deep understanding of your application’s performance and health. This will enable you to identify and resolve issues quickly, improve your service reliability, and deliver a better experience for your users. Moving beyond the default metrics and focusing on your key SLIs is essential for effective cloud monitoring.