EC2 Instance Reachability Issues

Here are some steps to troubleshoot and resolve this issue:

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### 1. **Check Instance Resource Usage**
– **Run Commands via SSH:** Log into your instance using SSH (`ssh ubuntu@your-ec2-host`) and monitor resources.
– **Check System Load:**

top
     htop  # If installed

Ensure the CPU and memory usage aren't maxed out.
– **Check Disk Space:**

df -h

If the disk is full, free up space by removing unnecessary files.

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### 2. **Logs for Clues**
– Review system logs for errors:

sudo cat /var/log/syslog | grep -i error
     sudo dmesg | grep -i error

– Review application logs for errors related to `yarn run dev`.

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### 3. **Adjust `yarn run dev` Settings**
The development server (`yarn run dev`) can consume significant resources. To prevent it from overloading:
– Limit the number of watchers:

export CHOKIDAR_USEPOLLING=true
     export MAX_WORKERS=2  # Adjust workers based on instance capacity
     yarn run dev

– Ensure you're running `yarn run dev` in a screen or tmux session to avoid losing the process if disconnected.

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### 4. **Upgrade EC2 Instance**
If your current instance lacks sufficient resources:
– Upgrade to an instance with more CPU, memory, or network capacity.
– Consider using a **burstable instance** (e.g., `t2.medium`) for short periods of high resource usage.

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### 5. **Improve Network Stability**
– Ensure the **security group** associated with your EC2 allows incoming and outgoing traffic for necessary ports.
– Verify that the instance's **Elastic IP** or DNS configuration is stable and correctly set.

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### 6. **Set Up Monitoring**
Use AWS tools to identify root causes:
– **CloudWatch Alarms:** Set alarms for high CPU, memory, or disk usage.
– **Detailed Monitoring:** Enable detailed instance monitoring for deeper insights.

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### 7. **Recovery**
– If the instance becomes unreachable, restart it from the AWS Management Console.
– If SSH fails, try connecting via the **EC2 Instance Connect** feature in the console.

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### Long-Term Solution
Instead of running `yarn run dev` directly on your EC2 instance for production:
– **Switch to `yarn build`:** Build the application locally or on a build server, then deploy the static files to the EC2 instance.
– **Use a Process Manager:** Use `pm2` or `supervisor` to manage the development server process to prevent crashes.

Let me know if you’d like help with any of these steps!