Exam AZ-900 - Azure Fundamentals - Part 1

Ronald Mariah · July 28, 2019

This is the first blog post in a series which will cover the exam content for AZ-900 (Azure Fundamentals).

The AZ-900 exam is intended for candidates with non-technical backgrounds, such as those involved in selling or purchasing cloud based solutions and services or who have some involvement with cloud based solutions and services, as well as those with a technical background who have a need to validate their foundational level knowledge around cloud services. Technical IT experience is not required however some general IT knowledge or experience would be beneficial.

For an overview of the exam content, you can find it one the Microsoft Exam Page

In Part 1, I will cover what’s required for the topic Understand cloud concepts

This topic in the exam accounts for 15-20% of the questions and is broken down as follows:

  • Describe the benefits and considerations of using cloud services
    • understand terms such as High Availability, Scalability, Elasticity, Agility, Fault Tolerance, and Disaster Recovery
    • understand the principles of economies of scale
    • understand the differences between Capital Expenditure (CapEx) and Operational Expenditure (OpEx)
    • understand the consumption-based model
  • Describe the differences between Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS)
    • describe Infrastructure-as-a-Service (IaaS)
    • describe Platform-as-a-Service (PaaS)
    • describe Software-as-a-Service (SaaS)
    • compare and contrast the three different service types
  • Describe the differences between Public, Private and Hybrid cloud models
    • describe Public cloud
    • describe Private cloud
    • describe Hybrid cloud
    • compare and contrast the three different cloud models

The following is a list of useful links which cover the concepts required for the exam objectives.

  • Describe the benefits and considerations of using cloud services
    • High Availability is a characteristic of a system, which aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. This agreed level of operational performance or uptime on Azure is governed by SLAs. As an example, the SLA for a Single Instance Virtual Machines with Premium Storage is 99.9%. To calculate the amount of expected downtime, use this tool.

    • Scalability is the property of a system to handle a growing amount of work by adding resources to the system. In Azure, compute resources like Virtual Machine Scale Sets, support automatic scaling, which means that, if the load on a single machine is above a certain threshold, the Azure platform will add more resources to the Scale Set.

    • Elasticity is defined as “the degree to which a system is able to adapt to workload changes by provisioning and de-provisioning resources in an autonomic manner, such that at each point in time the available resources match the current demand as closely as possible”. In Azure, using the same example of Virtual Machine Scale Sets, when the load on a single Virtual Machine is above the threshold, we can dynamically provision more resources to match this demand. When the load decreases below the threshold, the amount of resouces (VMs) are removed to match the demand. Elasticity in cloud ensures that we are not running more resources than we need at any given time.

    • Agility refers to the rapid provisioning of computer resources. Cloud environments can usually provide new compute instances or storage in minutes, a far cry from the very common weeks (or months, in some organizations) the same provisioning process can take in typical IT shops. As one could imagine, the dramatic shortening of the provisioning timeframe enables work to commence much more quickly. No more submitting a request for computing resources and then anxiously watching e-mail for a fulfillment response. As agility may be defined as “the power of moving quickly and easily; nimbleness” it’s easy to see how this rapid provisioning is referred to advancing agility.

    • Fault Tolerance is about designing a blueprint for continuing the ongoing work whenever a few parts are down or unavailable. Main Concepts behind Fault Tolerance in Cloud Computing System Replication: The fault tolerant system works on the concept of running several other replicates for each and every service. Thus, if one part of the system goes wrong, it has other instances that can be placed instead of it to keep it running. Take for example, a database cluster that has 3 servers with the same information on each of them. All the actions like data insertion, updates, and deletion get written on each of them. The servers, which are redundant, would be in the inactive mode unless and until any fault tolerance system doesn’t demand the availability of them. Redundancy: When any system part fails or moves towards a downstate, then it is important to have backup type systems. For example, a website program that has MS SQL as its database may fail in between due to some hardware fault. Then a new database has to be availed in the redundancy concept when the original is in offline mode. The server operates with the emergency database which comprises of several redundant services within.

    • Disaster Recovery involves a set of policies, tools and procedures to enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster. Disaster recovery focuses on the IT or technology systems supporting critical business functions,[1] as opposed to business continuity, which involves keeping all essential aspects of a business functioning despite significant disruptive events. Disaster recovery can therefore be considered as a subset of business continuity.

    • Economies of Scale is the ability to do things more efficiently or at a lower-cost per unit when operating at a larger scale. This cost advantage is an important benefit in cloud computing. Cloud providers such as Microsoft, Google, and Amazon are large businesses leveraging the benefits of economies of scale, and then pass the savings onto their customers. These savings are apparent to end users in a number of ways, one of which is the ability to acquire hardware at a lower cost. Cloud providers can also make deals with local governments and utilities to get tax savings, lowering the price of power, cooling, and high-speed network connectivity between sites. Cloud providers are then able to pass on these benefits to end users in the form of lower prices than what you could achieve on your own.

    • CapEx vs OpEx - CapEx is the spending of money on physical infrastructure up front, and then deducting that expense from your tax bill over time. CapEx is an upfront cost, which has a value that reduces over time. OpEx is spending money on services or products now and being billed for them now. You can deduct this expense from your tax bill in the same year. There’s no upfront cost. You pay for a service or product as you use it.

    • Consumption-based model is a service provision and payment scheme in which the customer pays according to the resources used. This model is essentially the same as the utility computing payment structure and those of other utilities, such as water and electricity. In this model, the provider may charge a flat rate for all resources per time used or may charge at different rates for various components of the service. In short, on Azure you pay for what resources you use, and stop paying for them when the resources are removed.

  • Describe the differences between Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS)
    • Infrastructure-as-a-Service (IaaS) - In an IaaS model, a cloud provider hosts the infrastructure components traditionally present in an on-premises data center, including servers, storage and networking hardware, as well as the virtualization or hypervisor layer. In this model, the customer is responsible for maintaining the servers provisioned by the cloud provider, including software updates and ensuring that patches are applied accordingly.
    • Platform-as-a-Service (PaaS) Platform as a service (PaaS) is a cloud computing model in which a third-party provider delivers hardware and software tools – usually those needed for application development – to users over the internet. A PaaS provider hosts the hardware and software on its own infrastructure. As a result, PaaS frees users from having to install in-house hardware and software to develop or run a new application. In the PaaS model, the customer does not need to worry about maintaining the underlying server infrastructure; this is maintained by the cloud provider. The customer is responsible for the application that runs on the PaaS service.
    • Software-as-a-Service (SaaS) is a software distribution model in which a third-party provider hosts applications and makes them available to customers over the Internet. In the SaaS model, the customer does not have the ability to manage the underlying infrastructure or configure the application. The service is used as provided by the cloud provider. Examples of this is Office 365, OneDrive, Salesforce, Oracle etc.
  • Describe the differences between Public, Private and Hybrid cloud models
    • Public Cloud is defined as computing services offered by third-party providers over the public Internet, making them available to anyone who wants to use or purchase them. They may be free or sold on-demand, allowing customers to pay only per usage for the CPU cycles, storage, or bandwidth they consume.
    • Private Cloud is defined as computing services offered either over the Internet or a private internal network and only to select users instead of the general public. Also called an internal or corporate cloud, private cloud computing gives businesses many of the benefits of a public cloud - including self-service, scalability, and elasticity - with the additional control and customization available from dedicated resources over a computing infrastructure hosted on-premises.
    • Hybrid Cloud is a computing environment that combines a public cloud and a private cloud by allowing data and applications to be shared between them. When computing and processing demand fluctuates, hybrid cloud computing gives businesses the ability to seamlessly scale their on-premises infrastructure up to the public cloud to handle any overflow—without giving third-party datacenters access to the entirety of their data. Organizations gain the flexibility and computing power of the public cloud for basic and non-sensitive computing tasks, while keeping business-critical applications and data on-premises, safely behind a company firewall.

Microsoft also provides a learning path for the concepts covered in the exam, which can be found on the Microsoft Docs

The other topics covered in the exam will be in Part 2 of my blog.


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