Server Is Stopping Frequently

When an EC2 instance keeps shutting down frequently, there are several potential causes to investigate:

1. Resource constraints: Your instance may be running out of memory, CPU, or disk space. This is a common issue, especially with smaller instance types like t2.micro or t3.micro that have limited resources (1GB of memory). When running multiple services (like web servers, databases, and applications), these resources can be quickly exhausted.

2. Operating system initiated shutdown: If there's no "StopInstances" event in CloudTrail, the shutdown might be initiated by the operating system itself due to crashes, kernel panics, or other OS-level issues.

3. Application issues: Problems with your application code could cause crashes or resource leaks that eventually make the system unresponsive.

4. Out of Memory (OOM) killer: When a system runs critically low on memory, the Linux kernel's OOM killer may terminate processes to free up resources, which can affect your application's stability.

To troubleshoot and resolve this issue:

1. Check the "State transition message" for your instance in the EC2 console when it's in the stopped state. This can provide clues about why it stopped.

2. Review system and application logs for error messages or warnings:

• System logs: /var/log/syslog or /var/log/dmesg
• Application-specific logs depending on what you're running

3. Monitor resource usage with tools like htop or free -m to identify potential memory or CPU constraints.

4. Consider upgrading your instance type if resource constraints are the issue.

5. Implement proper logging in your application to capture any errors that might be causing it to crash.

6. Use a process manager like Supervisor or systemd to automatically restart your application if it crashes.

7. Add a swap file if memory constraints are the issue, though this is a temporary solution.

8. Install the CloudWatch agent to collect and monitor memory metrics, which aren't available by default in the EC2 console.

Without seeing the terminal image you tried to share or knowing more details about your specific setup, these are the most common causes and solutions for EC2 instances that frequently stop or become unresponsive.
Sources
Instance or Server keeps shutting down | AWS re:Post
Windows server EC2 is constantly shutting down | AWS re:Post
EC2 stops running intermittently | AWS re:Post
EC2 Ubuntu instance stops working everyday | AWS re:Post