Why observability matters in GCP - See It in Action

Why observability matters

📖 Scenario: You are managing a cloud application on Google Cloud Platform (GCP). You want to understand how your application behaves and quickly find problems when they happen.Observability helps you see inside your system like a doctor uses a stethoscope to listen to a patient’s heartbeat. It shows you logs, metrics, and traces so you can keep your app healthy.

🎯 Goal: Build a simple GCP monitoring setup that collects logs and metrics from a virtual machine instance and creates an alert policy to notify you if CPU usage is too high.

📋 What You'll Learn

Create a GCP Compute Engine VM instance with logging enabled

Set up a metric to monitor CPU utilization

Create an alert policy for CPU usage above 80%

Verify the alert policy is linked to the VM instance

💡 Why This Matters

🌍 Real World

Cloud engineers use observability to keep applications running smoothly by detecting issues early and understanding system behavior.

💼 Career

Knowing how to set up monitoring and alerting on GCP is essential for roles like Cloud Engineer, Site Reliability Engineer, and DevOps Engineer.

1

Create a GCP Compute Engine VM instance with logging enabled

Write a Terraform resource block named google_compute_instance called vm_instance that creates a VM instance with the name observability-vm in the zone us-central1-a. Enable the metadata enable-oslogin with value true and set the machine type to e2-medium. Also, enable the logging agent by adding the metadata google-logging-enabled with value true.

GCP

# Your code here

Need a hint?

Use resource "google_compute_instance" "vm_instance" and set metadata keys for logging and OS login.

2

Set up a metric to monitor CPU utilization

Create a Terraform resource block named google_monitoring_metric_descriptor called cpu_utilization_metric that defines a custom metric with the type custom.googleapis.com/cpu/utilization. Set the metric kind to GAUGE and the value type to DOUBLE. Add a description "CPU utilization metric for VM".

GCP

resource "google_compute_instance" "vm_instance" {
  name         = "observability-vm"
  machine_type = "e2-medium"
  zone         = "us-central1-a"

  metadata = {
    "enable-oslogin"        = "true"
    "google-logging-enabled" = "true"
  }

  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }

  network_interface {
    network = "default"
    access_config {}
  }
}

# Define a custom metric for CPU utilization
# Your code here

Need a hint?

Use google_monitoring_metric_descriptor resource with the specified type and properties.

3

Create an alert policy for CPU usage above 80%

Add a Terraform resource block named google_monitoring_alert_policy called cpu_alert_policy. Set the display name to "High CPU Usage Alert". Add a condition with the display name "CPU usage above 80%" that triggers when the metric custom.googleapis.com/cpu/utilization is above 0.8 for at least 5 minutes. Use the combiner OR.

GCP

resource "google_compute_instance" "vm_instance" {
  name         = "observability-vm"
  machine_type = "e2-medium"
  zone         = "us-central1-a"

  metadata = {
    "enable-oslogin"        = "true"
    "google-logging-enabled" = "true"
  }

  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }

  network_interface {
    network = "default"
    access_config {}
  }
}

resource "google_monitoring_metric_descriptor" "cpu_utilization_metric" {
  type        = "custom.googleapis.com/cpu/utilization"
  metric_kind = "GAUGE"
  value_type  = "DOUBLE"
  description = "CPU utilization metric for VM"
}

# Create an alert policy for CPU usage above 80%
# Your code here

Need a hint?

Use google_monitoring_alert_policy with a condition_threshold for the custom CPU metric.

4

Link the alert policy to the VM instance

Add a notification_channels attribute to the google_monitoring_alert_policy resource called cpu_alert_policy. Use a placeholder string "projects/my-project/notificationChannels/1234567890" to simulate a notification channel ID.

GCP

resource "google_compute_instance" "vm_instance" {
  name         = "observability-vm"
  machine_type = "e2-medium"
  zone         = "us-central1-a"

  metadata = {
    "enable-oslogin"        = "true"
    "google-logging-enabled" = "true"
  }

  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }

  network_interface {
    network = "default"
    access_config {}
  }
}

resource "google_monitoring_metric_descriptor" "cpu_utilization_metric" {
  type        = "custom.googleapis.com/cpu/utilization"
  metric_kind = "GAUGE"
  value_type  = "DOUBLE"
  description = "CPU utilization metric for VM"
}

resource "google_monitoring_alert_policy" "cpu_alert_policy" {
  display_name = "High CPU Usage Alert"
  combiner    = "OR"

  conditions {
    display_name = "CPU usage above 80%"

    condition_threshold {
      filter     = "metric.type = \"custom.googleapis.com/cpu/utilization\""
      comparison = "COMPARISON_GT"
      threshold_value = 0.8
      duration   = "300s"
    }
  }

  # Add notification channel here
  # Your code here
}

Need a hint?

Add notification_channels attribute with the placeholder notification channel ID inside the alert policy resource.