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.
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Reference: amazon.com/Exam-AZ-900-Microsoft-A...