Interview Scenario Troubleshooting Application Issues

Hi, I'm Rob. And I'm Candace. Congrats on making it through this course. Now that you've made it this far, we're here to give you a sneak peek into what an interview on the technical subjects covered by this course might look like. We hope this will help you have a better idea of what to expect in your next interview. Just remember to keep learning and keep practicing.

Scenario

Let's say that you stopped by to see a user at their desk and they reported some kind of application issue. When you get there, they show you the problem. They're trying to launch an application from a shortcut on their desktop and every time they double-click on it, they get this generic error message:

Start troubleshooting that for me.

Interviewer Questions

1. What OS are you using and what's the name of the application?

• Say it's Linux desktop and it's a custom application, let's call it Application X.

2. Do you remember the last time this worked?

• Sure, we can say it worked on Friday and today's Monday.

3. Do you know if there are any other users experiencing this issue?

• This is the first report of it, but it's still early on a Monday.

4. Are you aware of any updates that happened over the weekend?

• Not that I'm aware, but is there any way we can check?

5. How can we check if there was an update?

• We can check the apt log.

6. What is apt?

• Apt is a utility used to install applications and updates.

7. Can you walk me through where we can find the logs for apt?

• I'm actually not sure where the logs are located.

8. How might you find this out in a real-world scenario?

• We can check the man page or search online.

9. Let's say you find the log in /var/log/apt and the file is history.log. How do you find specific information for Application X?

• We can use the grep command with the application name.

10. Suppose you find an update done just over the weekend. What’s next?

• The update could have caused the issue. Check for missing dependencies or application corruption. Also, check permissions.

11. How do you proceed with checking permissions?

• First, get the location by right-clicking on the shortcut and checking the command section. Use the which command to find the location. For example, /usr/bin. Navigate to the directory and list permissions with ls -l.

12. What does the permission string -rwx r-x --- mean?

• r stands for read, w stands for write, and x stands for execute. The first set of three is for the owner, the second set is for the group, and the last set is for others. Root root means the owner and group are both root.

13. Does anything stand out from the permission string?

• Yes, there are no read or execute permissions for others, which might be causing the issue.

14. How do you correct this?

• Use the chmod command to update the permissions.

15. After fixing the permissions, what should be done?

• Notify the owners of the application to prevent recurring issues and inform users affected by the problem.

Summary

In this scenario, we saw a lot of back and forth, which is common in troubleshooting interviews. The candidate used several follow-up questions to narrow down the problem. Since the error message was unclear, various potential causes were explored. Finding the actual cause involved eliminating the most likely issues first. It's okay not to know everything; demonstrating resourcefulness and the ability to find answers is crucial.

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Technical Interview Scenario: Troubleshooting Application Issues on Linux 🐧🔍

Scenario Overview

You are an IT support specialist addressing an issue where a user is unable to launch a custom application on their Linux desktop. The application displays a generic error message when attempting to start. Here's a step-by-step guide to troubleshooting this issue effectively.

1. Initial Questions and Investigation 🔍

• Identify the OS and Application:

  • OS: Linux Desktop

  • Application: Custom-built application X

• Determine Last Known Working State:

  • Last Known Working Date: Friday (today is Monday)

• Check for Other Users:

  • Reports from Others: No additional reports yet

• Check for Recent Updates:

  • Update Logs: Use apt to check recent updates.

2. Finding and Analyzing Logs 📜

• Locate Logs:

  • Command: apt logs are located in /var/log/apt, specifically in history.log.

• Search for Application-Specific Entries:

  • Command: Use grep to find entries related to application-X.

3. Update and Dependency Management 🔄

• Run System Updates:

  • Commands:

    • sudo apt-get update

    • sudo apt-get upgrade

• Check if Issue Persists:

  • Action: Attempt to launch the application again.

4. Check Application Permissions 🔐

• Find Application Location:

  • Command: Right-click on the shortcut to get the command path, e.g., application-X.

  • Verify Location: Use which application-X to confirm path, e.g., /usr/bin/application-X.

• Navigate to Application Directory:

  • Command: cd /usr/bin

• List Permissions:

  • Command: ls -l application-X

  • Typical Output: -rwx r-x --- root root

5. Understanding and Modifying Permissions 🛠️

• Permission Breakdown:

  • r: Read

  • w: Write

  • x: Execute

  • Owner Permissions: rwx (read, write, execute)

  • Group Permissions: r-x (read, execute)

  • Other/User Permissions: --- (no permissions)

• Correct Permissions:

  • Command: chmod 755 application-X (adds read and execute permissions for others)

6. Final Steps and Follow-Up ✅

• Test Application:

  • Outcome: Application should now launch successfully.

• Notify Application Owners:

  • Action: Inform the owners of the issue and resolution to prevent future occurrences.

Key Takeaways 🌟

• Effective Troubleshooting: Begin with broad questions, narrow down the issue, and methodically check possible causes.

• Resourcefulness: Utilize available tools and commands to gather information and solve problems.

• Communication: Keep stakeholders informed about issues and resolutions.

By following these steps, you can effectively diagnose and resolve application issues on Linux, demonstrating your problem-solving skills and resourcefulness in technical interviews. 🌐🛠️