Unleashing the Power of Observability: Serverless Monitoring and Logging with AWS CloudWatch - Part 2
Published: 2023-07-21 14:48:50

**Part 2: Collecting and Monitoring Serverless Metrics**

Welcome to the second part of our blog series on "Unleashing the Power of Observability: Serverless Monitoring and Logging with AWS CloudWatch." In this post, we'll focus on metrics, a critical component for understanding the performance of serverless functions. We'll cover how to enable CloudWatch metrics for AWS Lambda functions and explore the available metrics to gain valuable insights into your serverless application's behavior.

## **Enabling CloudWatch Metrics for AWS Lambda Functions**

Enabling CloudWatch metrics for AWS Lambda functions is a straightforward process that allows you to start collecting valuable data about the performance of your serverless application.

**1. Using the AWS Management Console:**

Step 1: Go to the AWS Management Console and navigate to the Lambda service.

Step 2: Select your Lambda function from the list and click on "Monitoring" in the navigation menu.

Step 3: In the Monitoring tab, you'll find the option to enable CloudWatch metrics. Simply click on the "Edit" button and choose "Enable" to start collecting metrics.

**2. Using the AWS Command Line Interface (CLI):**

You can also enable CloudWatch metrics for your Lambda function programmatically using the AWS CLI.

```bash
aws lambda put-function-concurrency --function-name YourLambdaFunctionName --reserved-concurrent-executions 100
```

By enabling CloudWatch metrics, you'll gain insights into essential performance metrics like the number of invocations, duration, errors, and throttles, which will help you optimize your serverless application.

## **Exploring Available Metrics for AWS Lambda Functions

Once you've enabled CloudWatch metrics for your Lambda function, you can explore and analyze a wealth of valuable data.**

**1. Using the AWS Management Console:**

Step 1: Go to the AWS Management Console and navigate to the CloudWatch service.

Step 2: In the navigation pane, click on "Metrics."

Step 3: Under "All metrics," select "AWS/Lambda" as the Namespace.

Step 4: You'll see a list of available metrics for your Lambda functions, such as "Invocations," "Duration," "Errors," "Throttles," and more.

**2. Using the AWS CLI:**

You can programmatically retrieve the available CloudWatch metrics for your Lambda functions using the AWS CLI.

```bash
aws cloudwatch list-metrics --namespace "AWS/Lambda" --metric-name "Invocations" --dimensions Name=FunctionName,Value=YourLambdaFunctionName
```
The metrics provided by CloudWatch will give you a comprehensive view of how your Lambda function is performing and help you identify any areas that may need improvement or optimization.

## **Creating Custom Metrics for AWS Lambda Functions**
In addition to the default metrics provided by CloudWatch, you can create and publish custom metrics to monitor specific aspects of your serverless application.

**1. Using the AWS SDK:**

You can use the AWS SDK for your preferred programming language to publish custom metrics to CloudWatch.

**Python Example:**

```python

import boto3

cloudwatch = boto3.client('cloudwatch')
response = cloudwatch.put_metric_data(
    Namespace='CustomMetrics',
    MetricData=[
        {
            'MetricName': 'CustomMetric',
            'Value': 1,
            'Unit': 'Count'
        },
    ]
)

```

Custom metrics allow you to track application-specific data and business metrics, enabling you to make informed decisions based on the behavior of your serverless functions.

## **Conclusion**
In this post, we focused on the importance of metrics in understanding the performance of serverless functions. We explored how to enable CloudWatch metrics for AWS Lambda functions using both the AWS Management Console and the AWS CLI. Additionally, we learned how to explore the available metrics and how to create and publish custom metrics for more tailored monitoring.

In the next part of our blog series, "Centralized Logging with CloudWatch Logs," we'll delve into how to enable CloudWatch Logs for Lambda functions and effectively manage and analyze logs to gain deep insights into your serverless applications. Stay tuned for more exciting insights and practical examples on leveraging AWS CloudWatch for effective observability in your serverless architecture.