Checking EC2 Instance Logs in CloudWatch: A Comprehensive Guide


Monitoring the health and performance of virtual servers is crucial in cloud computing. Amazon EC2 instances provide valuable logs that offer insights into application performance and system behavior.

Amazon CloudWatch enhances this by enabling the collection, access, and analysis of these logs. This guide simplifies the process of integrating EC2 logs with CloudWatch, providing a clear, step-by-step approach.

Learn how to prepare your instances for logging, send logs to CloudWatch, and analyze them for actionable insights. This streamlined guide covers the essentials for optimal application performance and system health monitoring.

Understanding EC2 Logs and CloudWatch: Quick Start Guide

Overview of EC2 Logs

Amazon EC2 instances generate logs that are crucial for monitoring the health and performance of your applications. Key types of logs include:

  • System Logs: Capture the operating system level activities.
  • Application Logs: Record the outputs of applications running on the instances.

Understanding and monitoring these logs help in troubleshooting and optimizing application performance.

Integrating EC2 Logs with CloudWatch

Amazon CloudWatch provides a centralized platform to collect, view, and analyze logs from EC2 instances. Here’s how to leverage CloudWatch for your EC2 logs:

  1. Log Collection: CloudWatch aggregates logs from multiple sources, including EC2, offering a unified view of your infrastructure’s health.
  2. Real-time Monitoring: Access and monitor logs in near real-time to quickly identify and respond to issues.
  3. Analysis and Insights: Use CloudWatch features like dashboards and alarms to analyze log data and gain actionable insights.

Getting Started with CloudWatch

To start using CloudWatch for monitoring EC2 logs, follow these steps:

  1. Log in to AWS Management Console and navigate to the CloudWatch service.
  2. Create Log Groups: Organize your logs by creating log groups based on application, environment, or any criteria that fit your needs.
  3. Set Up Alarms: Configure alarms in CloudWatch to notify you of critical issues detected in your logs.

Best Practices

  • Regularly Review Logs: Make it a habit to check your CloudWatch dashboards and alarms to stay ahead of potential issues.
  • Leverage Log Insights: Use CloudWatch Log Insights for advanced query capabilities to delve deeper into your log data.

By understanding the types of logs your EC2 instances generate and integrating them with CloudWatch, you can enhance your monitoring strategy.

This guide simplifies the process, focusing on actionable steps to help you quickly set up and get value from your EC2 and CloudWatch integration.

Preparing Your EC2 Instance for Logging

Before diving into the specifics of monitoring logs with CloudWatch, it’s critical to ensure your EC2 instances are properly configured to send logs to CloudWatch. This involves several key steps: setting up the necessary IAM roles, creating log groups in CloudWatch, and configuring your instances to push logs.

Configuring IAM Roles and Permissions

The first step in preparing your EC2 instance for logging involves setting up an IAM role that grants your instance the permissions needed to interact with CloudWatch. This IAM role must have policies attached that allow it to put log data into CloudWatch Logs. Creating an IAM role involves:

  1. Navigating to the IAM console.
  2. Creating a new role and selecting the EC2 service for the role type.
  3. Attaching policies such as CloudWatchAgentServerPolicy that grant permissions to send logs to CloudWatch.
  4. Assigning this role to your EC2 instance.

Setting Up Log Groups in CloudWatch

After configuring the necessary IAM roles, the next step is to set up log groups in CloudWatch. Log groups serve as containers for your log streams and can be organized by application, environment, or any other criteria that suit your organizational needs. Creating log groups is straightforward:

  1. Go to the CloudWatch console.
  2. Navigate to Logs and choose ‘Create log group’.
  3. Name your log group following a naming convention that reflects its purpose (e.g., /aws/ec2/my-application-production).

With these foundational steps completed, your EC2 instances are now ready to send logs to CloudWatch. Each of these steps plays a crucial role in ensuring that your logging infrastructure is secure, organized, and optimized for efficient log management and analysis.

The subsequent sections will delve into the specifics of sending logs from EC2 to CloudWatch and leveraging CloudWatch features to monitor and analyze log data effectively.

Sending Logs from EC2 to CloudWatch: A Step-by-Step Guide

Step 1: Ensure IAM Role Configuration

Before installing the CloudWatch agent, make sure your EC2 instance is assigned an IAM role with the necessary permissions. This role should have the CloudWatchAgentServerPolicy attached, allowing it to send logs to CloudWatch.

Example IAM Policy Attachment:

aws iam attach-role-policy --role-name YourEC2RoleName --policy-arn arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy

Step 2: Install the CloudWatch Agent

Connect to your EC2 instance via SSH and use the following commands to download and install the CloudWatch agent. Adjust the commands based on your instance’s operating system.

For Amazon Linux 2:

sudo yum install -y amazon-cloudwatch-agent

For Ubuntu:

sudo dpkg -i -E ./amazon-cloudwatch-agent.deb

Step 3: Configure the CloudWatch Agent

Use the amazon-cloudwatch-agent-config-wizard to generate the agent configuration file. This wizard will guide you through selecting log files, metrics collection, and other settings.

sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-config-wizard

After completing the wizard, your configuration will be saved in a JSON file (typically located at /opt/aws/amazon-cloudwatch-agent/bin/config.json). You can manually edit this file for further customization.

Step 4: Start the CloudWatch Agent

With the configuration file in place, start the CloudWatch agent using the following command:

sudo /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/opt/aws/amazon-cloudwatch-agent/bin/config.json -s

Step 5: Verify Log Data in CloudWatch

After the agent starts, it will begin sending specified logs to CloudWatch. Verify your logs are being sent by navigating to the CloudWatch console in AWS, selecting “Logs” from the navigation pane, and then choosing the relevant log group.

By following these steps above, you can configure your EC2 instance to send logs to CloudWatch, enabling you to monitor and analyze your application and system logs effectively.

Monitoring and Analyzing EC2 Logs in CloudWatch

Monitoring and analyzing EC2 instance logs in CloudWatch is a powerful capability that enables you to gain insights into the performance and health of your applications. CloudWatch provides the tools to not only access and view these logs but also to analyze them and set up alarms for specific events.

Accessing Logs

To access logs in CloudWatch, navigate to the CloudWatch console, and select ‘Logs’ from the navigation pane. Here, you’ll find the log groups that you’ve configured for your EC2 instances. Clicking on a log group will display the individual log streams that contain the actual log data.

Log Insights

For deeper analysis, CloudWatch Log Insights allows you to run queries against your log data. This is useful for extracting specific information, such as error rates or usage patterns. To use Log Insights, select it from the CloudWatch console, choose the relevant log group, and enter your query. CloudWatch provides a variety of sample queries to get you started.

Monitoring and analyzing logs in CloudWatch provides a comprehensive view of your application’s performance. Through proactive monitoring and detailed log analysis, you can identify potential issues before they impact your users, ensuring a seamless and efficient operation of your services on AWS. You can also leverage Lambdas to custom process your logs to derive additional insights.

Viewing Logs in CloudWatch

Accessing and viewing EC2 instance logs in CloudWatch is straightforward. After logs have been successfully transmitted to CloudWatch, they can be viewed within the AWS CloudWatch console. Here’s how:

  1. Open CloudWatch Console: Log in to your AWS Management Console, navigate to the Services menu, and select CloudWatch.
  2. Navigate to Logs: Inside the CloudWatch console, find the ‘Logs’ section on the left navigation pane.
  3. Select Log Group: Your EC2 instance logs will be organized into log groups. Select the log group associated with your EC2 instance.
  4. View Log Streams: Within a log group, logs are further organized into streams. Click on a log stream to view the detailed logs.

This process allows you to easily check the logs of your EC2 instances, helping you to troubleshoot issues, monitor system health, and understand application performance in real-time.

Setting Up Alarms Based on Log Events

CloudWatch Alarms can be configured to alert you based on specific events within your EC2 instance logs. This feature is instrumental in identifying and responding to potential issues promptly. Here’s how to set it up:

  1. Navigate to CloudWatch: In the AWS Management Console, go to the CloudWatch service.
  2. Create Alarm: Select ‘Alarms’ from the navigation pane, then choose ‘Create alarm’.
  3. Select Log Metric: Choose ‘Select metric’, navigate to ‘Logs’, and pick the metric filter associated with your EC2 log events.
  4. Configure Alarm: Specify the conditions under which the alarm should be triggered, such as error thresholds or specific log patterns. Then, set the actions to be taken when the alarm state is met, like sending a notification via Amazon SNS.

By setting up alarms based on log events, you can ensure that you’re immediately notified of critical issues, allowing for swift action to maintain optimal performance and availability of your applications on AWS.

Best Practices for EC2 Log Management in CloudWatch

Effective log management is crucial for maintaining the reliability, performance, and security of your AWS resources. Here are some best practices for managing EC2 logs in CloudWatch:

  1. Use Structured Logging: Structured logs are easier to query and analyze. Ensure your application logs are output in a structured format, such as JSON, to facilitate efficient log processing and analysis.

  2. Implement Log Retention Policies: Configure log retention settings in CloudWatch to automatically delete old log data that is no longer needed. This helps in managing costs and ensuring compliance with data retention policies.

  3. Secure Log Data: Use IAM roles and policies to control access to your log data in CloudWatch. Ensure that only authorized personnel can view or manipulate the logs.

  4. Monitor and Alert on Critical Events: Make use of CloudWatch Alarms and metrics to monitor critical events within your logs. Setting up alerts for unusual activity or error rates can help you respond to issues quickly.

  5. Optimize Costs: Be mindful of the volume of log data you’re sending to CloudWatch. Use filters to send only relevant log data, and consider using CloudWatch Logs insights for cost-effective log analysis.

By following these and our CloudWatch best practices, you can ensure that your EC2 logs are managed effectively in CloudWatch, providing you with the insights needed to maintain and optimize your AWS resources.


This guide showed you how to work with EC2 and CloudWatch to check on your application’s health. We talked about setting things up, watching over your logs, and some tips to do it well. Remember, it’s about making sure your applications run well and stay secure. Keep an eye on your logs, use alarms to catch problems early, and manage your logs smartly to avoid unnecessary costs. With these practices in place, you can ensure that your applications on EC2 run smoothly and efficiently.


How do I integrate EC2 logs with CloudWatch?

To integrate EC2 logs with CloudWatch, assign an IAM role with CloudWatchAgentServerPolicy to your EC2 instance, install the CloudWatch agent, configure it to specify which logs to send, and then start the agent. This setup allows you to monitor and analyze your application and system logs in CloudWatch.

What types of logs can I monitor with CloudWatch from EC2 instances?

You can monitor system logs, which capture operating system activities, and application logs, which record the outputs of applications running on your EC2 instances. Both provide insights into the performance and health of your applications.

How do I set up alarms based on EC2 log events in CloudWatch?

To set up alarms, navigate to the CloudWatch console, select ‘Alarms’, choose ‘Create alarm’, select the metric filter associated with your log events, and configure the conditions for the alarm. This allows you to be alerted about critical issues promptly.

What are the best practices for managing EC2 logs in CloudWatch?

Best practices include using structured logging for easier analysis, implementing log retention policies to manage costs, securing log data with IAM roles and policies, monitoring critical events with alarms, and optimizing log data volume to reduce costs.