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AZ900-Exam Ref by Jim Cheshire Chapter 1 Skill 1.3

Lemilletrente1030 — Fri, 07 Feb 2025 23:22:04 +0000

Cheshire started by discussing the definition of an utterly fundamental concept: the cloud. He first gave a rough explanation of the cloud to which he would complement not long after that; according to Cheshire, cloud represents infrastructure and application that can be accessed through the Internet, and with which we can have somewhat control over authentication. Personally, I always imagine cloud as a network of remote servers that store, manage and process data over the internet instead of local machines, and the resources can be accessed with an internet connection.

Moreover, as Cheshire added, we should always think of cloud computing as we think of cloud, he suggested to not only consider it as many computing resources connected by network, but a scalable and agile system as well. Still, it remains tricky to clearly understand the cloud definition. At the moment, it is best to dive into three types of cloud deployment model to better understand what cloud computing is.

Public Cloud

The most common and traditional there is, public cloud and SaaS share various similarities. Essentially, it is an infrastructure provided by a third-party provider, resources are shared among all users. Like SaaS, public cloud offers scalability, in-place and pre-configured infrastructure, accessible through the Internet, multi-tenancy and pay-as-you-go pricing. Unlike SaaS, public cloud is not a software application and can include either IaaS, PaaS or SaaS. Some prime examples of public cloud are AWS, Microsoft Azure and GCP. In simplest terms, public cloud is like house rental and SaaS is like hotel.

There are four main drawbacks to public cloud: security risks, limited control, compliance issues and latency. Security threats stem from it being public and can be available to anyone with an internet connection, and from it being a shared resources, meaning high risk of data breach. Cloud providers will of course aide us to some extent, but might not live up to our standards. Just as with SaaS, public cloud also has a control liberty trade-off where we are locked to certain settings and thus are unable to response to specific needs, leading to unnecessary costs and compliance issues. Lastly, the latency, as a matter of course, is caused by its reliance on the Internet.

Private Cloud

An attractive deployment model with notable benefits, private cloud is dedicated to a single organisation coupled with high security features. Firstly, it is either hosted on-premise or by a third-party provider and so it comes with high privacy and control. This is the common motive why companies like financial and healthcare ones choose this model, these organisations usually have strict regulations to comply with and have demands to keep some data inaccessible to public internet. Other advantages might include higher performance and manageable costs.

Obviously, there is always a catch. This option is, as can be expected, more expensive than the previous one, sometimes it costs just as much as hiring an IT team but instead we'll need to hire IT staff to mange software and infrastructure. Additionally, if we want to cut the cost by resorting to a third-party host, we will lose control over data privacy aspect. At the end of the day, nothing is truly perfect!

Hybrid Cloud

A combination of both private and public cloud, hybrid cloud is suitable for companies with legacy on-site systems that want to balance benefits from the cloud and the expensive costs come with it. So, they only move parts of a particular system while store the data on-premise. Keep in mind that this is a just one of the many scenarios where we will need hybrid cloud for the job, there are countless more in which hybrid cloud is the way to go. Hybrid cloud combines the best of both worlds.

On the other hand, a highlighted cons of hybrid cloud is high complexity. It can be a hassle to juggle between public and private, ensuring they are compatible, troubleshooting network infrastructure at third-party providers, and so on. Moreover, we will encounter latency due to the transferring of data between public and private cloud, between the geographical location of the system running the app and the data the app uses. All of these have to be carefully assessed before opting for hybrid cloud.

AZ900-Exam Ref by Jim Cheshire Chapter 1 Skill 1.2

Lemilletrente1030 — Fri, 31 Jan 2025 23:01:32 +0000

Previously we have learnt about several cloud advantages. Now lets three common cloud service models.

Shared Responsibility Model

Depending on our goals, we will need different types of control on our assets, that also means we will have more responsibility in the system. This responsibility sharing is the main differences between today's service models. The most common way to visualise this is by using a triangle hierarchy diagram.

To decide which service model best fits our plans, it is best to understand their portions of control and responsibility, along with their pros and cons. So lets dive in the first one right now, IaaS!

Infrastructure-as-a-Service (IaaS)

Infrastructure of an application includes all the necessary and foundational components, systems and resources needed to develop and deploy the application. I want to firstly start with the key components of an application infrastructure.

Processing power: processing power are those that deal with the application's logic and workloads, such as physical hardware and virtual machines.
Storage: this is where application's data, files and configurations are stored.
Networking: where communication between application components and users are enabled.
Development and deployment tools
Application layer: not to be confused with the application layer in the OSI model, this is where we apply components and code to deliver functionalities to users.
Logging and monitoring: to track performance, identify issues and ensuring availability.
Security: to protect the application and its data from potential threats.
Disaster redundancy and recovery: to ensure availability in the event of natural catastrophes.
Cost management: tools and strategies for cost-efficiency.

Cloud IaaS will provide all of the above except for application layer and development and deployment environment. Additionally, we will also benefit from management and automation tools as well as data centres, virtualization technology and operating systems on VMs.IaaS will give us control over cloud resources, so, once again, we have the responsibility to cater for the patching and troubleshooting, though Microsoft will give access to various helping tools for those tasks.

Cost benefits of IaaS and pay-as-you-go align closely as both emphasize flexibility, cost-efficiency and scalability. In short, IaaS service is the best choice if we want another party to manage the hardware infrastructure part of our application.

Platform-as-a-Service (PaaS)

This is the best service for developers as it provides the platform for test, deploy and manage application without worrying about the underlying infrastructure (e.g: VMs are now entirely managed by cloud providers). Here, middleware, software that sits between applications and the underlying infrastructure, is also introduced, we can get some extent of control over it depending on the provider. PaaS is the right choice for us if we want to offload the unnecessary and complex setup/ management work.

Additionally, thanks to the PaaS perks, we are able to move from on-premise to a pre-built cloud environment pretty seamlessly without the hassle of configurations, set up and database migration. Moreover, because cloud providers control the OS and what's installed in the VMs, we are also benefited from being able to add features as easy as flipping a switch. Lastly, PaaS offers all the enhancement from the cloud that I have written in my previous blog, which are effective cost management, auto-scaling, fault-tolerant, disaster recovery and so on.

Here, Cheshire also provides one drawback of PaaS, that is the lack of liberty to decide when to upgrade our VMs. This is one of the expected disadvantages when giving over the control of low-level configuration. This same factor also causes several following issues. First, many PaaS providers use proprietary technologies, which makes transferring from Google App Engine to AWS, for example, require extra work. Secondly, we will suffer from limited customisation and security risk. This, too, is the result of limiting out access to underlying structure. There is still more drawbacks but I will not include them all in this article.

Software-as-a-Service (SaaS)

In this service, we are literally presented with cloud-based apps of which infrastructure is completely controlled by the provider, we can access these over the internet without the need to control, manage, install or maintain infrastructure, middleware or software update. As a result, most of them are well known: Google workspace, Microsoft 365, Slack, Zoom, Google Drive and OneDrive to name a few. Please note that all SaaS apps are cloud apps but not all cloud apps are SaaS apps, some cloud-based apps are custom-built.

One huge benefits of SaaS is that it can be accessed from a web browser, which means we can take advantage of the software from any device, ultimately boosting our connectivity and productivity. What's more, we can benefit from the fact that SaaS software maintained and configured by the cloud provider, this is particularly useful in the entreprise environment when we can have a business-oriented software ready to use instead of hiring IT staff for that job. Still, SaaS service is not limited to entreprise, but personal use as well. One prime example of that is Gmail, we have it both as an app and as a web-app, we have new features, updates and, even if we don't realize, regular patch from time to time.

Comparing The Service Types

Let's quickly go through three types once last time.

IaaS offers the most control along with responsibility, and thus the greatest flexibility. The payment model being PAYG allows use to optimize the budget, converting capital expense to operational expense, thought the benefit is offset as we have to do the maintenance work.

PaaS offers the same flexibility, with less control over infrastructure. We are responsible for our own application, PaaS is also a go-to option for dev teams seeing that it presents various deployment tools and middleware as well as way more features than the previous service. Cost will increase unintendedly by the updates and version change of the underlying software.

SaaS offers the lowest scalability as the it is tight to provider's offering, so it is all about whether they meet our demands or not. In SaaS, IT-related burden is lifted along with high accessibility, as long as we have Internet access we are good to go. SaaS is for both business owners and non-tech users as all the technical work is well taken care of. In exchange, there will be no customization or liberty in configuration.

AZ900-Exam Ref by Jim Cheshire Chap. One Skill 1.1

Lemilletrente1030 — Fri, 24 Jan 2025 20:04:25 +0000

As a cloud beginner, I chose to pick up the AZ-900 exam to familiarize myself with the landscape. AZ-900 is one of the very first exams newcommers in cloud industry have to take on in order to advance to other high-level certificates. Although I have no intention of using the certificate in the next two years, I believe this affordable certification will help me build foundational knowledge for further advanced exams. This blog series will be about my notes on AZ900-Exam Ref by Jim Cheshire - a prep book for the AZ-900 exam.

Chapter One Overview

For each chapter, the author splits them into 3 main parts: the skills (main lessons), thought excercises and chapter summary; at the beginning of every chapter, there is a general introduction to the main topics that are going to be covered. This is a format that I really love as it allows me to be curious throughout the lessons and at the end be able to go through all the concepts once again and apply them into practical scenarios.

Chapter one concerns several fundamental cloud concepts: IaaS, PaaS and PaaS; as well as three basic types of cloud deployment models.

Cloud Advantages

I am a pragmatic person, it is not a brag as I usually find it really difficult to focus on learning something if I don't know its application in real world beforehand. Fortunately, the author has given the general ideas of what cloud technology can do in this day and age. Thanks to that , I can clearly see why cloud is so vital to an organisation. Let's go through several benefits now.

Availability

Availability may be the most important factor in the CIA triad for service provision. With cloud technology, cloud service providers can guarantee an uptime of near 100 percent as long as they are systems controlled by them. Concerning downtime, there are a few scenarios we have to take into account:

Network outage
Application failure
System outage
Power outage

The reasons for these downtime are usually overlapping, such as human error, natural disasters, resources distribution, software and hardware issues. The other reasons are more domain-specific like electric grid failure, cable cuts, critical system components failure or software-level problems. Cloud technology addresses a significant portion of these causes thanks to its fault-tolerant design, resource redundancy, elastic scaling, proactive monitoring and IAM to name a few.

Elasticity, Scalability and Agility

These are the terms that I get really confused. All three concern flexible resource management, yet each focuses on different aspects.

Also known as auto-scaling, elasticity refer to the dynamic changing of resources in response to demands, pursuing optimal cost and performance.

Agility describes cloud's feature of quick adjustments of supply according to needs. For example, Microsoft Azure will provide more virtual machines to us and allocate resource in seconds, all we have to do is to tell them how many more do we need then we're up and running.

Scalability is the process of adding/ removing resources and power for our application. We have scaling horizontally (scaling out) which means adding more resources quantity-wise (i.e: adding more VMs), whereas vertically scaling (scaling up) means improving quality for the current application (i.e: adding more powerful CPU or more memory).

Fault Tolerance and Disaster Recovery

Things are not always going to work our ways. Accidents are bound to happen from time to time, to maintain the highest level of availability, however, azure presents a wide range of solutions. Here concerns two of them: proactive monitoring and replicating data.

Briefly, microsoft provides a system that will monitor our resources' health and can sometimes automate the fixing process without us ever noticing (i.e: auto-scaling resources based on workloads), optimally securing availability.

To counter circumstances where natural phenomena damage physical assets like data centers, one of solution in this chapter is geo-distribution. By setting up abundant datacenters in regions and multiple availability zones in each region for damaged areas to failover to other unscathed service provision spots. I find this solution pretty brilliant and am impressed by how powerful cloud technology is.

Cost Benefits

Moving to cloud is a huge profitable movement for businesses. One of most common payment method for cloud service is pay-as-you-go, which only charges when we consume the resource and is for unpredictable workloads.

Here is my favorite analogy: we are required to read a book without knowing the number of pages in a matter of a week and reading it all is not mandatory. We decided to hire a book renting service that only charges when we open the book instead of buying the whole book. This is beneficial because:

We are only charged for times we are reading (payment only for usage).
The pages can adjust their brightness, material, fonts and letter size to personal preferences (elasticity, change according to demands).
We do not have to pay for the extra pages that we have yet to read at the end of the deadline (avoiding wasted resource).
Our book can have fixes and quality improvements instead of hiring a "page-maintenance team" (maintenance costs).
We can use any addtional accesories if needed without extra purchases (access to cutting-edge technology without buying expensive license or hardware) As a result, this book-renting agency comes out as the best option to go for considering we only need the book for a week (short-term projects) without knowing the length of the book (unpredictable workload pattern). Though, it will be less profitable if we will have tasks involved leaving the book open for an extended period of time (or if we forget to close it after each use of course).

Conclusion

Above is my brief skill 1.1 notes, we have gone through the advantages of cloud technology, its ability to secure availability in many different ways as well as the cost benefits of using a cloud service. What I have covered is just a scratch on the surface of what cloud can offer to business environments as well as personal use. But with these, I do believe we have what it takes to step to the next topic of skill 1.2, three basic types of cloud service models: IaaS, PaaS and SaaS.

Introduction to My Blog

Lemilletrente1030 — Fri, 17 Jan 2025 12:23:16 +0000

When I moved abroad, one of my biggest priorities became finding my passion. The pursuit felt exhilarating and, at times, daunting. After so many self-study sessions, I’ve explored a multitude of fields: namely data science, quant finance, algorithmic trading, quantum computing, blockchain development, machine learning, critical infrastructure cybersecurity and cloud security. It sounds a lot right? In fact, to me, it was more like a discovery than mastery. All I did was just posing a lot of questions to ChatGPT, conducting thought experiments, and taking free courses to learn about those fields at surface-level knowledge.

Every time I moved from one subject to another, I would ask myself, “Am i wasting time?” My answer was always, “Absolutely not.” I believe that each exploration brought me closer to understanding myself—my strengths, values, and what excites me. The whole process was not about finding my passion overnight, rather, it was about knowing myself, crafting a vision for the future and identifying how I could bring value to the world. I have always been inspired by IKIGAI, the Japanese concept of purpose, perhaps because I was surrounded by passionate people growing up.

One field with which I really got hooked up was CIC. Learning about PLCs, RTUs or HMI fascinated me more than building dashboard, coding a smart contract or training a neural network. I spent a great deal of my time diving into this field. Reality set in overtime, though, I was discouraged by the role's geographically constraints, the lack of vibrant community and the high prices of the courses. I knew it would not fit right long-term, but I did not leave empty-handed, I had an important take: I want to break into cybersecurity.

With further research, I found cloud security the most intriguing and there are several reasons why. Firstly, the missions and responsibilities of a cloud security professional excite me. One of my favorite strategies to evaluate my interest in a field is to learn about the projects and typical tasks involved. I am thrilled by the idea of safeguarding critical systems, solving complex security challenges, and ensuring the safety of data in a cloud environment.

Secondly, the flexibility for remote work aligns well with my future plans. For the moment, I am still undecided between pursuing an on-site or remote job, the flexibility that cloud security offers gives me a sense of freedom and adaptability that I value deeply.

Lastly, the diverse career pathways. I love that this field provides opportunities to work in various sectors such as healthcare, finance, or even blockchain to name a few. This versatility aligns with my broader goal of combining cybersecurity expertise with cross-disciplinary knowledge to make a meaningful impact across different domains.

Following my decision to pursue cloud security, I decided to craft a blog documenting my learning experience, whether in cloud security or other fields that intrigue me. The blog serves several purposes. First, it is my reflection on my learning journey, allowing me to represent what I have learnt thus further detect my challenges and deepen my understanding. Secondly, practicing my writing skills to hone my ability to express myself articulately. Lastly, I hope to connect with professionals in the field. Additionally, I hope this blog will make a great reference material for others in the future, it can be used as a roadmap that captures someone's triumphs and trials in striving to be an experienced professional from a complete beginner