Linux Question 4

This lesson outlines a high-level design for creating a Linux script that automatically transfers specific log files to an S3 bucket at scheduled intervals. This approach is commonly discussed in interviews to assess your ability to design solutions using Linux and AWS best practices.

High-Level Design Overview

The goal is to securely and efficiently move log files from a Linux server to an S3 bucket. The design includes several key components:

1. Authentication & Permissions

   Ensure the Linux server has the proper permissions to interact with S3. This can be achieved using one of two methods:

   • IAM Role: If the server is configured with an IAM role that has S3 access permissions, no additional configuration is needed.
   • IAM Access Keys: If using IAM access keys, configure them properly on the server via the AWS CLI or environment variables.

2. Script Structure with Shebang

   Begin your Bash script with a shebang (#!/bin/bash) to specify the interpreter. This step ensures that the script runs in the appropriate shell environment.

3. Identifying Log Files
   Determine where the target log files are stored. For this example, assume that the logs reside at:
   /var/log/application/application-01

4. Using AWS CLI to Copy Files to S3
   Use the AWS CLI to copy log files from the local disk to the S3 bucket. The command follows this basic structure:

   aws s3 cp <origin> <S3 location>
   

   Replace <origin> with the local log file path and <S3 location> with the destination S3 bucket path.

5. Scheduling with Linux Cron Jobs
   To automate the transfer, schedule the script using a cron job. Configure the cron job to execute the script at regular intervals or specific times, ensuring ongoing synchronization of your log files.

Detailed Explanation Illustrated with a Diagram

The diagram below provides a high-level visual overview of the architecture. It demonstrates how IAM roles or access keys authenticate the Linux server, how the Bash script uses AWS CLI commands to transfer files, and how cron jobs ensure the process runs automatically.

Interview Presentation Tips

When presenting this solution in an interview, consider highlighting the following points:

• Explain how the Linux server will authenticate with AWS using either an IAM role or IAM access keys.
• Detail the structure of the Bash script, emphasizing the use of the shebang at the beginning.
• Describe how the log file location is determined and targeted for transfer.
• Clarify how the AWS CLI command (aws s3 cp) is employed to move the log files to the S3 bucket.
• Discuss the automation of this process via cron jobs, ensuring that log transfers occur at the required intervals.

This design not only demonstrates expertise in Linux scripting and AWS but also shows a solid grasp of automating tasks in a secure and systematic manner.

That concludes the explanation for this lesson. Thank you for reading, and best of luck with your future projects and interviews!