Friday, February 3, 2023

Azure interview questions

1.    Azure Cloud?

Microsoft Azure is a cloud computing services provided by internet giant Microsoft. It allows users to build, test, host or manage web applications and data. Microsoft has its own data center infrastructure across the world which provides over 600 kind of cloud services. The direct and major competitor of Microsoft Azure is Amazon Web Services, commonly called as AWS. Apart from that it does compete with Google Cloud and Alibaba Cloud which are quite behind.

2.    Microsoft Azure Data Center Locations?

Microsoft Azure has similar way of classifying the location. Mainly, it uses Geographies (mostly countries, continents as well), Regions (cities) and availability zones. In fact, almost all of the major cloud infrastructure providers these days follow this pattern to describe their data center locations.

Geographies

Since Microsoft has used both continents and countries as geographies, for your convenience, we have separated out each such geographies on the basis of continents in our world political map.

Regions and Availability Zones

Regions are mainly the cities that host one or more availability zones in the area. Availability zones are unique cluster of one or more data centers interconnected with same low-latency network, power source and cooling system. Such “availability zones” are independent to other availability zones in the region or outside. They are tolerant to data center failure through redundancy and logical isolation of services.

Azure availability zones are connected by a high-performance network with a round-trip latency of less than 2ms. They help your data stay synchronized and accessible when things go wrong. Each zone is composed of one or more datacenters equipped with independent power, cooling, and networking infrastructure. Availability zones are designed so that if one zone is affected, regional services, capacity, and high availability are supported by the remaining two zones.

To ensure resiliency, a minimum of three separate availability zones are present in all availability zone-enabled regions.

1.    What is an availability set?

An availability set is a logical grouping of VMs that allows Azure to understand how your application is built to provide for redundancy and availability. We recommended that two or more VMs are created within an availability set to provide for a highly available application and to meet the 99.95% Azure SLA. There is no cost for the Availability Set itself, you only pay for each VM instance that you create.

2.    How Availability set is working? or What is update domain and fault domain?

Every VM that is deployed into an availability set is assigned an update domain and a fault domain by Microsoft Azure.

An availability set contains five update domains by default, although this can be increased to 20 update domains in resource manager deployments. An update domain is a group of virtual machines and underlying physical hardware that can be rebooted at the same time. When planned maintenance is performed on the Azure platform, only one update domain is rebooted at a time. This ensures that all VMs and associated hardware are not taken down at the same time.

a fault domain is a group of virtual machines that shares a common power source and a common network switch. When virtual machines are added to an availability set, they are distributed across up to three different fault domains in resource manager deployments, or across two fault domains in classic deployments.

Deploying VMs in an availability set will not protect an application from failures associated with the operating system of the VMs or from failures that are application-specific. However, placing virtual machines in an availability set will provide protection against network outages, physical hardware failures, and power interruptions within an Azure data center.

Availability zones are similar in concept to availability sets. However, there is a distinct difference. While availability sets are used to protect applications from hardware failures within an Azure data center, availability zones, protect applications from complete Azure data center failures.

3.    Azure Cloud Services roles?

There are two types of Azure Cloud Services roles. The only difference between the two is how your role is hosted on the VMs:

·       Web role: Automatically deploys and hosts your app through IIS.

·       Worker role: Does not use IIS, and runs your app standalone.

For example, a simple application might use just a single web role, serving a website. A more complex application might use a web role to handle incoming requests from users, and then pass those requests on to a worker role for processing. (This communication might use Azure Service Bus or Azure Queue storage.)

4.   General Cloud role?

·       Owner - Has full access to all resources including the right to delegate access to others.

·       Contributor - Can create and manage all types of Azure resources but can't grant access to others.

·       Reader - Can view existing Azure resources.

·       User Access Administrator - Lets you manage user access to Azure resources.

5.    What is the scalability of cloud computing?

Vertical scaling, where the configuration yields to increase the existing capacity of the machine. Just like expanding the size of the RAM from 4GB to 32GB.

Horizontal Scaling, an aspect where the physical aspect is increased like putting multiple machines at work instead of replacing the existing machine.

6.   Differentiate between the verbose and minimal monitoring?

Verbose mode means that there will be a higher volume of events that are sent as compared with similar information for non verbose mode.

Verbose monitoring collects metrics based on the performance that enables close analysis of data that fed during the processing of application whereas the minimal monitoring is a default configuration that makes the use of the performance counters gathered from the operating system of the host.

7.    How is the price of the Azure subscription placed?

The prices vary in accordance with the product type. The various pricing models are;

·       The free model where our customers can avail the system exempted from the market fee.

·       The BYOL scheme where the Azure is fetched the Azure with a fee that is not encircled around the limits of market price.

·       The trial of the free software where the client gets the full version with an advanced feature for a limited period of time. With the expiration of the introductory period, you will be charged standard rates.

·       Usage Based Fee that is billed in accordance with the service that you have taken. Like if you are subscribed for the virtual image then hourly fees may be charged.

·       Monthly bills are activated if you sign a particular plan. The fee is not allocated for cancellation or mid-month unused service.


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