Tutorial: AWS Certified Developer - Associate (DVA-C02)

Differences between logging, monitoring, and observability

Concepts

Understanding the differences between logging, monitoring, and observability is crucial for AWS Certified Developer – Associate candidates, as these concepts are integral to developing, deploying, and managing applications effectively on the AWS platform.

Logging

Logging is the act of capturing and storing information about events that occur within an application or infrastructure. This can include errors, warnings, and informational messages. Logs are typically generated in a structured format, such as JSON or XML, which can then be consumed by other systems for analysis.

In AWS, services like Amazon CloudWatch can be configured to collect logs from various AWS resources such as EC2 instances, Lambda functions, and more. AWS CloudTrail is another service that provides a record of actions taken by a user, role, or AWS service.

For example, an AWS Lambda function might generate logs every time it is invoked, including information about its execution status and any errors that occurred:

import logging import json


logger = logging.getLogger()

logger.setLevel(logging.INFO)
def lambda_handler(event, context):

    # Your business logic here

logger.info('Event: ' + json.dumps(event)) # If an error occurs logger.error('Error: Error message here')

Monitoring

Monitoring is a broader concept that involves the ongoing collection, visualization, and analysis of logging data to assess the performance and health of systems and applications. Monitoring systems often provide real-time visibility into these metrics, such as CPU usage, memory consumption, response times, and throughput.

In AWS, CloudWatch offers monitoring capabilities by allowing you to set alarms and trigger notifications based on metrics that it gathers. Amazon CloudWatch can create dashboards to visualize the performance of AWS resources, giving developers and operators an at-a-glance view of their applications’ health.

An example of setting up a monitoring alarm with CloudWatch might look like the following:

{ "AlarmName": "High CPU Utilization", "MetricName": "CPUUtilization", "Namespace": "AWS/EC2", "Statistic": "Average", "Period": 300, "EvaluationPeriods": 2, "Threshold": 90.0, "ComparisonOperator": "GreaterThanThreshold", "AlarmDescription": "This alarm will trigger when the average CPU utilization exceeds 90% over a 10-minute period." }

Observability

Observability is an attribute of a system that allows for understanding its internal states through external outputs, which can be logs, metrics, and traces. It’s a holistic approach that encompasses logging and monitoring but focuses on the ability to ask questions about the system’s behavior and health without adding new instrumentation.

The AWS X-Ray service provides observability by offering insights into how applications are performing and where bottlenecks or issues might be occurring. It allows you to trace requests as they flow through your system, enabling you to identify latency issues and see the impact of changes or new code deployments.

Here’s a brief comparison table that outlines the key aspects of each concept:

Aspect	Logging	Monitoring	Observability
Focus	Capturing detailed information about events.	Tracking the performance and health of systems.	Understanding system behavior through external outputs.
Tools in AWS	CloudWatch Logs, CloudTrail.	CloudWatch Alarms, CloudWatch Metrics, Dashboards.	AWS X-Ray, CloudWatch Logs Insights.
Usage	Root cause analysis, debugging.	Alerting, real-time analysis, historical analysis.	Performance analysis, tracing, problem solving.
Data Types	Logs (structured/unstructured).	Metrics (quantitative).	Logs, metrics, traces (qualitative and quantitative).
Actionability	Low without analysis.	High with proper alarms and thresholds set up.	High with the right queries and instrumentation.

Ultimately, developers preparing for the AWS Certified Developer – Associate exam should understand how logging, monitoring, and observability work together to enable robust application development and deployment on AWS. They should be familiar with the AWS services that provide these capabilities and how to leverage them to maintain performant and reliable cloud-based applications.

Answer the Questions in Comment Section

True or False: Logging is the core component of observability.

A) True
B) False

Answer: B) False

Explanation: Logging is a part of observability but not the core component. Observability is a broader concept encompassing logging, monitoring, and tracing to gain a comprehensive understanding of the system state.

Which of the following are benefits of monitoring? (Select two)

A) Isolating system failures
B) Understanding user behavior
C) Storing application logs
D) Reducing the amount of data collected

Answer: A) Isolating system failures, B) Understanding user behavior

Explanation: Monitoring helps in isolating system failures by tracking the health and performance of applications and infrastructure. It can also provide insights into user behavior by analyzing usage patterns and performance metrics.

Observability enables which of the following? (Select two)

A) Real-time data analytics
B) Deep system insights through correlated data
C) Automated code deployment
D) Cost reduction in data storage

Answer: A) Real-time data analytics, B) Deep system insights through correlated data

Explanation: Observability allows for real-time data analytics and deep system insights by correlating logs, metrics, and traces, granting developers the ability to understand complex system behaviors.

True or False: Logs are time-stamped records of discrete events that have happened over time.

A) True
B) False

Answer: A) True

Explanation: Logs are indeed time-stamped records of events, which provide insight into the behavior of the system at a specific point in time.

Which AWS service is primarily used for logging?

A) AWS CloudTrail
B) AWS CloudWatch
C) AWS X-Ray
D) AWS Config

Answer: B) AWS CloudWatch

Explanation: AWS CloudWatch is the service that provides logging capabilities, allowing you to collect and track metrics, collect and monitor log files, and set alarms.

Which AWS service is primarily used for application performance monitoring?

A) AWS CloudTrail
B) AWS CloudWatch
C) AWS X-Ray
D) AWS Config

Answer: C) AWS X-Ray

Explanation: AWS X-Ray helps developers analyze and debug production, distributed applications, such as those built using a microservices architecture. It provides insights into application performance and issues.

Monitoring typically involves:

A) Only real-time data analysis
B) Collecting, aggregating, and analyzing data over time
C) Generating and storing time-stamped event logs
D) Correlating logs, metrics, and traces for insights

Answer: B) Collecting, aggregating, and analyzing data over time

Explanation: Monitoring involves the collection, aggregation, and analysis of data over time to determine system health, performance, and potential issues.

True or False: Observability is purely about collecting metrics and logs.

A) True
B) False

Answer: B) False

Explanation: Observability is not just about collecting metrics and logs; it’s about understanding the inner workings of the system through collected data, which may include metrics, logs, and traces.

True or False: Tracing is a part of logging.

A) True
B) False

Answer: B) False

Explanation: Tracing is not a part of logging; it’s a distinct activity that records the execution path through a system, generally using distributed tracing to understand request flows in microservices architectures.

Which of the following is a key difference between monitoring and observability?

A) Monitoring is about asking questions, observability is about answering them.
B) Monitoring is reactive, observability is proactive.
C) Monitoring does not involve using tools, observability does.
D) Monitoring provides context, observability provides data.

Answer: B) Monitoring is reactive, observability is proactive.

Explanation: Monitoring is generally reactive, dealing with issues as they arise based on predefined alerts and thresholds. Observability is proactive and focuses on understanding why those issues occurred and how the system behaves as a whole.

What is the primary purpose of logging in system operations?

A) To fix issues in real-time
B) To provide an audit trail of events and state changes over time
C) To automate application scaling
D) To render visualizations of application traces

Answer: B) To provide an audit trail of events and state changes over time

Explanation: The primary purpose of logging is to create a detailed and time-stamped record of events and state changes over time, which serves as an audit trail for system activity.

In the context of AWS, how is observability typically implemented?

A) Using a single AWS service
B) By employing a combination of AWS services like AWS CloudWatch, AWS X-Ray, and Amazon Elasticsearch Service for logs
C) By using third-party monitoring tools exclusively
D) Observability is not applicable in AWS environments

Answer: B) By employing a combination of AWS services like AWS CloudWatch, AWS X-Ray, and Amazon Elasticsearch Service for logs

Explanation: Observability in AWS is typically achieved through an integrated suite of AWS services like AWS CloudWatch for monitoring and metrics, AWS X-Ray for application performance debugging, and Amazon Elasticsearch Service for log data analytics and search.