Troubleshooting and Debugging Techniques https://www.coursera.org/learn/troubleshooting-debugging-techniques

Troubleshooting and Debugging Techniques   

https://www.coursera.org/learn/troubleshooting-debugging-techniques

 Main Area of Computer trouble shooting:

Hardware

    RAM ,    HARD DISK,     CPU , NETWORK

Software:

        OS bugs To see Log files , what is happening 

        Application Bugs.

RAM leaks,

Network Bandwidth Problem: to with Shapping give Priorities.

Some Linux/Python commands

$ top to see the memory is being used in the system

In widows 

    1 , "Event Viewer" to see Log file

    2. Performance Monitor

    3. Resource Monitor.

$ lsof    list of open files.

$ sudo lsof | grep deleted  && means list of opened files marked as <Deleted>

$ nice command to set priorities of application

Module 3

Crashes in Complex Systems

Complex contains many Servers and many Services Like your company have E-Commerce Website having many Servers

Find out / check Log files of 

    1. Specific Services

    2. General system Log files

Find out change done when system was in good state and in Bad state.

    1. Was we upgrade any software

    2. add any Hardware

Updated any new service like authentcation server,  any Database service or Database version.

OR changes done in other Back end servers like billing, inventory and procurment sytem

You found that there is some changes made in LOAD BALANCE in b/w front-end and Back-end services

SOLUTION is to Roll Back the services

For dealing with such type complex system , you must

        1. Check Log files

        2. Have good Monitoring System

        3. Use VCS like Git and GitHu.com , so you cane quickly Roll Back when needed

Module 3

Writing Effective Postmortems

Postmortem is documentation of miskates we done during the touble shooting , or may during the cration of problem/bug or any other MISBAT

Postmorterm is doc: what we learn from out mistakes

TO prevent the same issue occur again. 

No need to ducment to fix BLAME any person. But to doc: 

    1. What happens

    2. Why  happens

    3. Who is was diagonesed

    4. How it wsas fixed

    5. Figure that this may not occur in FUTURE. 

The problem was solve by ROLL BACKING to previous state.

Module 3

Practice Quiz: Handling Bigger Incidents

Congratulations! You passed!

Grade received 100%

To pass 80% or higher

1.

Question 1

Which of the following would be effective in resolving a large issue if it happens again in the future?

1 / 1 point

Incident controller

Postmortem

Rollbacks

Load balancers

Correct

Keep it up! A postmortem is a detailed document of an issue which includes the root cause and remediation. It is effective on large, complex issues.

2.

Question 2

During peak hours, users have reported issues connecting to a website. The website is hosted by two load balancing servers in the cloud and are connected to an external SQL database. Logs on both servers show an increase in CPU and RAM usage. What may be the most effective way to resolve this issue with a complex set of servers?

1 / 1 point

Use threading in the program

Cache data in memory

Automate deployment of additional servers

Optimize the database

Correct

You got it! Automatically deploying additional servers to handle the loads of requests during peak hours can resolve issues with a complex set of servers.

3.

Question 3

It has become increasingly common to use cloud services and virtualization. Which kind of fix, in particular, does virtual cloud deployment speed up and simplify?

1 / 1 point

Deployment of new servers

Application code fixes

Log reviewing

Postmortems

Correct

Right on! Virtualization makes deployment of VM servers in the cloud a fast and relatively simple process.

4.

Question 4

What should we include in our postmortem? (Check all that apply)

1 / 1 point

Root cause of the issue

Correct

Sweet! In order to learn about the problem and how it happens in general, we should include what caused it this time.

How we diagnosed the problem

Correct

Awesome! By clarifying how we identified the problem, it can be more easily identified in the future.

How we fixed the problem

Correct

Excellent! In order to share with reviewers how the issue was resolved, it's important to include what we did to solve it this time.

Who caused the problem

5.

Question 5

In general, what is the goal of a postmortem? (Check all that apply)

1 / 1 point

To identify who is at fault

To allow prevention in the future

Correct

Way to go! By describing the cause of the problem, we can learn to avoid the same circumstances in the future.

To allow speedy remediation of similar issues in the future

Correct

Woohoo! By describing in detail how we fixed the problem, we can help others or ourselves fix the same problem more quickly in the future.

To analyze all system bugs

Module 4

Getting to the Important Tasks

Time Optimization is Hard task

Splits tasks in two categories

1. Urgent/Not Urgent

2. Important / Not Important

Important and Urgent Example: Internet of company down. You to restore internet connection from Backup as soon as possible ASAP

2. Example of Important but not Urgent is Long Term Plannings, like: Researching new technologies, Planning RollBack systems (Alayee Chaa)changing whole coding from FoxPro to Python and Implementation of DBMS system like MySQL instead of .dbf files 

3. Example of Ugrent But Not important:

a. Answer emails

b. Phone calls

c. 

4. Example of Not urgent and Not important

a. Fazool Meetings

b. 

Technical Debt: (Loan)

All Solutions we done urgently , temporary, in emergency on Adhoc Basis, we do work around and even it is not the best solution , To be solved on Long Terms and Permanent solution, Long Term Remediations (Not sure, Alaye Chaa)

It also Tech: debt when new version of software released , but still you did not change , due to you have not time right now , to change it. Or the online, current users can not be distrubed.

Question

Which of the following describes a technical debt?

Restarting a web server that has suspended services.

Rewriting a program to prevent memory leaks.

Setting up traffic shaping to improve communication with remote services.

Adding a hard drive to make room to install the application.

Correct

You got it! Restarting a server is a quick-fix or short-term remediation, which is also known as technical debt.

Module 4 Prioritizing Tasks

Question

Using a basic structure to organize and prioritize tasks, what’s the next thing you should do after creating a list of all the tasks you need to complete?

Sort tasks in groups.

Assess the importance of each issue.

Complete most urgent tasks immediately.

Estimate the amount of effort.

Correct

Woohoo! The most urgent tasks should be done immediately after completing the list.

Module 4

Estimating the Time Tasks Will Take

Question

Which of the following factors will be most beneficial in estimating the time it will take for you to complete a specific project?

Be overly optimistic with your time.

Multiply the estimate by a random factor.

Double your time.

Compare time used to similar projects or tasks.

Correct

You nailed it! The best way to estimate time on a new project is to compare your estimate to similar tasks or projects completed previously.

Module 4

Communicating Expectations

Replacing a fualty keyboard OR preparating New computer for New employee. 

We must communicate/educate the user how much time it will take to solve his problem. If their problem is solve before they expect he will be very happy otherwise he will be frusted.

Also make priority of working , For example there is a problem in Database then it will affect the company, So High priority is to given to this problem instead of the problem which affects only one or two persons

Receive any problem must be in REPORT format , instead of Phone call or chat. So you can see the list of issues, instead of users distrub you in the middle of the task

To avoid frustations and to save the time there must be some pole new keyboard and new mice, from company.  By trusting the user they themself come and change the mouse and keyboard , if there old Keyboard/mouse is not working properly.

In the same way there must be some extra new computer systems, So that in case of any hardware fault occur, we must change/replace the faulty computer with new one immediately to save the time and frustration.

Then we try to repair/trouble shoot the faulty computer

Question

Which of the following is an example of a practical shortcut to resolve incidents in a datacenter related to hard drive pre-failures?

Spare drives

Automated RAID scripts

Spare servers

Automated server scripts.

Correct

Right on! Spare drives are a practical shortcut that can quickly replace hard drives in a pre-fail state.

Module 4

More About Making the Best Use of Our Time

Check out the following link for more information:

• https://blog.rescuetime.com/how-to-prioritize/

Practice Quiz: Managing Our Time

1.

Question 1

Using the Eisenhower Decision Matrix, which of the following is an example of an event or task that is both Important, and Urgent?

1 / 1 point

Office gossip

Replying to emails

Internet connection is down

Follow-up to a recently resolved issue

Correct

Great work! It’s important for users to have Internet to work, and it must be resolved right away.

2.

Question 2

You’re working on a web server issue that’s preventing all users from accessing the site. You then receive a call from user to reset their user account password. Which appropriate action should you take when prioritizing your tasks?

1 / 1 point

Reset the user's password

Create a script to automate password resets

Ask the user to open a support ticket.

Ignore the user, and troubleshoot web server.

Correct

Nice job! Ask the user to open a support ticket so that the request can be placed into the queue while you work on the most urgent issue at hand.

3.

Question 3

What is it called when we make more work for ourselves later by taking shortcuts now?

1 / 1 point

Technical debt

Ticket tracking

Eisenhower Decision Matrix

Automation

Correct

Right on! Technical debt is defined as the implied cost of additional rework caused by choosing an easy (limited) solution now instead of using a better, but more difficult, solution.

4.

Question 4

What is the first step of prioritizing our time properly?

1 / 1 point

Work on urgent tasks first

Assess the importance of each issue

Make a list of all tasks

Estimate the time each task will take

Correct

Awesome! Before we can even decide which task to do first, we need to make a list of our tasks.

5.

Question 5

If an issue isn't solved within the time estimate that you provided, what should you do? (Select all that apply)

1 / 1 point

Explain why

Correct

Nice work! Communication is key, and it’s best to keep everyone informed.

Drop everything and perform that task immediately

Give an updated time estimate

Correct

Great work! If your original estimate turned out to be overly optimistic, it’s appropriate to re-estimate.

Put the task at the end of the list

Module 4

Dealing with Hard Problems

Quotation from Brain  who is contributor of UNIX OS and Author C programming Book

MEANS: 

        Writting new program is Easier than Debugging an old program

First Advice during writting codes

Another advice during writting Codes

Before writting , document final goal of program/Application

Advice No 3:

        Before writting Code try to write TEST Codes. 

If the problem is not solving , then explain the problem to rubber duck, which is know as rubber duck debug

Question

When facing a problem with a service, which of the following examples can remediate the issue quickly for the short-term?

Create tests for the program before coding.

Develop codes in small chunks.

Ask someone who has solved the issue before for help.

Grab a cup of coffee.

Correct

Awesome! Someone who has solved the issue before can apply the short-term remediation right away, and long-term solutions can be discussed later.

  

Module 4

Proactive Practices  

   

Before implementing any software/application in production environment we must run 

1. Automatic Tests and

2. Manual Tests

In a testing environment.

It means for deploying new software you must not apply/deploy in all the computers at a time, But at first instent apply/deploy one few computers at first instant.

So to see logs files we do not need to see in each computer, instead of one place in one computer.

It can be super helpful.

We must keep DOCUMENTATION at one and easily accessable place like in Google PlayBooks

Question

Which proactive practice can you implement to make troubleshooting issues in a program easier when problems arise?

Use a test environment.

Build infrastructure for rollbacks.

Set up integration tests

Include debug logging in code.

Correct

Great work!. Including debug logging in code can make troubleshooting easier because logs can help pinpoint the actual issue, and speed up remediation.

Module 4

Planning Future Resource Usage

Question

You have a small rack of servers and other components that make up a virtual infrastructure. This rack hosts virtual machines that provide web services, and user file shares to employees in the local office, and immediate regional branches. Which component in the rack can be most easily planned for future growth?

CPU Capacity

RAM Capacity

NAS capacity

Network bandwidth

Correct

Nice job! Network Attached Storage (NAS) products from vendors like NetApp can provide additional shelves to add more storage as the website’s content, and users’ data increases in size.

Module 4

Preventing Future Problems

Implement the monitoring system. For

RAM

CPU

DISK storage 

and 

Network Bandwidth

E.g. If there 85% full , Monitoring system must generates ALERTS/WARNING. 

     Also report the developers , what did you do for work around.

Specify full report , what was bug, when it was occur...etc every thing you know about the problems and its temporary/Adhoc solutions

Question

Which of the following is the most effective way to prevent an issue in a program that you own from happening again?

Report a bug

Write a test

Monitor resources

Reproduction case

Correct

Great work! When updating code to fix an issue, create a new test to ensure the change performs the intended actions.

1. Module 4
2. More About Preventing Future Breakage

Check out some more info here:

• https://simpleprogrammer.com/understanding-the-problem-domain-is-the-hardest-part-of-programming/

• https://deploy.equinix.com/blog/explaining-failure-domains-sre-lifeblood/

• https://landing.google.com/sre/sre-book/chapters/effective-troubleshooting/

Practice Quiz: Making Our Future Lives Easier

Grade received 100%

To pass 80% or higher

1.

Question 1

Which proactive practice can you implement to make troubleshooting issues in a program easier when they happen again, or face other similar issues?

1 / 1 point

Create and update documentation

Use a test environment.

Automate rollbacks.

Set up Unit tests.

Correct

You got it! Documentation that includes good instructions on how to resolve an issue can assist in resolving the same, or similar issue in the future.

2.

Question 2

Which of the following is a good example of mixing and matching resources on a single server so that the running services make the best possible use of all resources?

1 / 1 point

Run two applications that are CPU intensive between two servers.

Run a CPU intensive application on one server, and an I/O intensive application on another server.

Run a RAM intensive application and a CPU intensive application on a server.

Run two applications that are RAM and I/O intensive on a server.

Correct

Great work! An application that uses a lot of RAM can still run while CPU is mostly used by another application on the same server.

3.

Question 3

One strategy for debugging involves explaining the problem to yourself out loud. What is this technique known as?

1 / 1 point

Monitoring

Rubber Ducking

Testing

Ticketing

Correct

Right on! Rubber ducking is the process of explaining a problem to a "rubber duck", or rather yourself, to better understand the problem.

4.

Question 4

When deploying software, what is a canary?

1 / 1 point

A test for how components of a program interact with each other

A test of a program’s components

A test deployment to a subset of production hosts

A small section of code

Correct

Nice job! Reminiscent of the old term "canary in a coal mine", a canary is a test deployment of our software, just to see what happens.

5.

Question 5

It is advisable to collect monitoring information into a central location. Given the importance of the server handling the centralized collecting, when assessing risks from outages, this server could be described as what?

1 / 1 point

A failure domain

A problem domain

CPU intensive

I/O intensive

Correct

Awesome! A failure domain is a logical or physical component of a system that might fail.

Module 4 Wrap Up: Managing Resources

Discussed what we learned in this course. Listed Topics.

Qwiklabs Assessment: Debugging and Solving Software Problems

===Existing Code===

import csv

import datetime

import requests

URL_FILE='https://storage.googleapis.com/gwg-content/gic215/employees-with-date.csv'

def get_start_date():

    year  = int(input('Enter Year====> ') or 2019)

    month = int(input('Enter Month===> ') or 1)

    day   = int(input('Enter day=====> ') or 1)

    return dateitme.datetime(year,month,day)

Module 4

Congratulations!

Module 4

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