Summary

This coursework is divided into two parts:

Part 1: A written task (only) related to the knowledge gained in the AWS Academy Cloud Foundations course (weeks 1-7).

Part 2: A combined practical and written activity architecting a scaling application on the Cloud,         where you will be required to use knowledge gained and a little further research to implement the   scaling infrastructure, followed by a report that will focus on your experience in the practical activity together with knowledge gained in the entire LSDE course.

Weighting: This assessment is worth 100% of your total unit 20 credits.

Set: 09:00. Monday 18th July 2022

Due: 13:00. Monday 8th August 2022.

Pre-requisites:

•    You must have completed the AWS Academy Cloud Foundations course set in weeks 1-8

•    You will require an AWS Academy Lab account for the practical activity. You should receive an invite when this document is released. Please contact the LSDE Unit Director if you have no invitation email or are having issues with the registration.

•    A Secure Shell (SSH) client, such as MacOS Terminal or PuTTy on Windows, for server admin.

Submission:

Via the LSDE BlackBoard coursework assessment page, submit one zip file (named ‘your_username.zip’, e.g. tl18303.zip), containing:

•    a Report (‘report.pdf’) in PDF format containing:

o Part 2

•    a Text File (‘credentials.txt’) containing your AWS Academy account credentials (username,

password), to enable us to access your AWS Academy Lab account as required.             In this document we provide a detailed explanation of the tasks and the approach to marking.

Task 1 : (25%)

Write a maximum of 1000 words (minimum: 600) debating the statement:

"Data Processing in the Public Cloud is More Reliable than in Traditional Data Centres" Include your own descriptions of the following:

•    At least 5 AWS features or services introduced in the Cloud Foundations course that ensure reliable data processing in the public cloud.

•    At least 3 different scenarios where data processing reliability may suffer in the public cloud.

Task 2: Scaling the WordPress Application (75%)

Overview

WordPress is by far the most popular open-source software for hosting online blogs and small-scale websites. It is a PHP application, backed by a MySQL database (NOTE: you are NOT expected to        understand or modify the source code in any way).

WordPress includes a password-secured browser admin interface that enables blog posts and other content to be created, management of users, review of blog metrics, installation of extensions         (known as ‘plugins’), and so on.

WordPress is typically installed on a single EC2 server, but as we saw in the Cloud Foundations          course, a single server has limitations in availability, scalability, performance, etc. This can affect the speed of response (latency) and thus performance and cost (see this article).

Your task will be to take a default, minimal installation of WordPress and implement a resilient,   highly available, scalable, cost effective and secure architecture for it on AWS. This will include     performing load testing on your application to demonstrate improved performance under stress.

You will be required to initially set up and test the application, using instructions given with the zip  download file. You will then need to identify how to scale and improve the application architecture, based on principles learned in the CF course. Finally, you will write a report covering this process,    along with some extra material.

Task A – Install the Application

Ensure you have set up access to your AWS Academy Lab account and have at least $20 credit (you are provided with $100 to start with). If you are running short of credit, please inform your               instructor.

Refer to the WordPress installation instructions in the coursework zip download on the BlackBoard   site, to install and configure the application in your AWS Academy Lab account. These instructions    do not cover every step – you are assumed to be confident in certain tasks, such as in the use of IAM permissions, launching an EC2 instance, etc.

You will set up a single server installation of WordPress, using a pre-built community AMI, then configure it appropriately for this assessment.

Before moving on to the next task, ensure that:

•    You can access the WordPress administration interface and can create & manage blog posts.

•    You have the required plugin(s) installed and configured.

•    You have successfully set up SSH (command line) access to the WordPress instance.

•    You have successfully set up the load testing site and run some trial load tests.

NOTE: The application and plugin code are programmed in the PHP language. You are NOT expected to understand or modify it. Any code changes will be ignored and may lose marks.

Task B - Design and Implement Auto-scaling

Review the architecture of the existing application. Although the website is usable for one visitor (client), when run under the load tester for multiple clients the response (latency) becomes          noticeably slow (5000ms / 5 seconds or more to load a page).

To better handle multiple clients, we need to add scaling to the application.

This should function as follows:

- When a given maximum performance metric threshold is exceeded, an identical WordPress              instance is launched (to a maximum of 3 instances) and begins to also respond to incoming requests.

- When a given minimum performance metric threshold is exceeded, the most recently launched WordPress instance is removed (terminated).

- There must always be at least one WordPress instance available to respond to incoming requests when the WordPress website architecture is 'live'.

Using the knowledge gained from the Cloud Foundations course, architect and implement auto-        scaling functionality for the WordPress application. You can refer to the Lab 6 in Module 10, which is also for a web application. You will need to identify a CloudWatch performance metric to use for the ‘scale out’ and ‘scale in’ rules – it’s wise to review CloudWatch metrics for the EC2 service after          running the application for a while under load, to pinpoint the most appropriate metric.

Task C - Perform Load Testing

Once you have set up your auto-scaling infrastructure, test that it works. Set (edit) the test in the load tester to use initially 250 clients, then 350 clients, then 500 clients.

If your autoscaling functionality is configured correctly, you should be able to achieve a latency        response of under 1 second with 500 clients. If the load tester produces an error during testing, the response time is too high and you will need to fine tune your auto scaling parameters more.

•    Watch the behaviour of your WordPress application, to check the scale out (add instances) and scale in (remove instances) behaviour works.

•   Take screenshots of the EC2 instance page showing launched / terminated instances along with the load tester graphs.

•   Try to optimise the scaling operation so that instances are launched quickly when required and terminated soon (but not immediately) when not required. Note settings you used and the fastest processing time you can achieve.

•   Try using a few different EC2 instance types – with more CPU power, memory, etc. Note down any changes in processing time.

NOTE: Academy Lab accounts are limited in which EC2 Types and services they can use.

Task D - Secure and Optimise the WordPress Architecture

Using services, features and techniques learned from the Cloud Foundations course, improve the architecture in the following areas:

•    Increase resilience and availability of the application against component failure.

•    Increase security of the application for data protection and prevent unauthorised access.

•    Consider how to ensure the application is as cost-effective (cheap to run) as possible.

NOTE 1: You will probably need to remove any WordPress instances in the process of upgrading your architecture. The Academy Lab accounts officially only allow a maximum of 3 auto-scaling                 instances, although you may be able to edit your Auto Scaling Group after creation to launch more    than 3. Ensure your application and scaling functionality still work after implementing your                  improvements!

NOTE 2: The Academy Lab account is limited in enabling full configuration of security features, so if your account prevents you from implementing your requirements, explain this in the final report.

Task E - Create the Final Report

Write a report of no more than 3000 words (which includes all text and figures) and no more than 15 pages in length (there is NO minimum length). This should include:

•    A brief summary of the benefits and pitfalls of the initial WordPress architecture in Task A.

•    Your design process to architect the scaling behaviours (task B).

•    An overview of the testing and your results, including screenshots (task C).

•    Your optimisation steps (task D).

•    Details of any issues you had and whether you resolved them.

Add one final section of the report: Further Improvements

•    Discuss (briefly): If you add a blog post to an instance in your scaled architecture, this post may not always appear if you have two or more instances running. Why is this?

•    Explain (at a high level): Based on services and frameworks covered in the LSDE course, describe step by step how you could fix the above issue using a relevant scalable, highly available, managed service of your choice.

[Do not implement this idea, just explain the basic workflow of configuring this for your WordPress architecture].

AWS Academy Labs

You are given an AWS Academy Lab account for this coursework. Each account has $100 assigned to it. View the Lab after logging in to your Academy account by going to Courses > AWS Academy            Learner Lab > Modules > Learner Lab (usually the second module). The remaining amount is updated every 24 hours and displayed on the Lab page. Please keep track of it!

Please note:

•   Starting a Lab session (‘Start Lab’) will allow you to run services such as EC2 for up to 4 hours for each session. Ensure you shut down (stop or terminate) EC2 instances when you are not  using them. These will use the most credit in your account in this exercise

•   AWS Academy Lab accounts have only a limited subset of AWS services / features available to them, see the BB Discussion Forum for details.

•   If you have any issues with Academy Labs, please book an Office Hours session or use the      LSDE Discussion Forums to seek help FIRST or email the instructor if there is no other option.

Support

The normal options for support are available for you, up until 8th August 2021:

•    Book Office Hours for tech questions/support in LSDE support calendar. If available dates are not shown, view page in browser:

https://outlook.office365.com/owa/calendar/ematlsdeofficehours@bristol.ac.uk/bookings/

•    Office Hours: will vary over the Summer – please check with the instructor

•    BB Discussions Forum