Azure Interview Questions

What is Azure Cloud Service?

Ans: By creating a cloud service, you can deploy a multi-tier web application in Azure, defining multiple roles to distribute processing and allow flexible scaling of your application. A cloud service consists of one or more web roles and/or worker roles, each with its own application files and configuration. Azure Websites and Virtual Machines also enable web applications on Azure. The main advantage of cloud services is the ability to support more complex multi-tier architectures

What are Azure App Services

Ans: We can develop an application in any language or framework, such as .NET, .NET Core, Java, Ruby, Node.js, PHP, or Python. Applications run and scale as per our need with complex architecture on both Windows and Linux-based environments. The App service has added the power of Azure to our application, such as security, load balancing, scaling, and automated management. We can also develop capabilities such as continuous deployment from GitHub, Docker Hub, Azure DevOps, and other sources, staging environments, SSL certificates, etc.

Azure App Service enables us to create web, mobile, logic and API apps very easily. We can run any number of these apps within a single Azure App service deployment. Our apps are automatically managed by Azure App Service and run in managed VMs isolated from other customers. We can also use built-in auto-scaling feature supported within Azure App Service that automatically increase and decrease the number of VMs based on consumption resources.

Why use App Service?

Ans: Here are some key features of App Service:

·         Multiple languages and frameworks - App Service has first-class support for ASP.NET, ASP.NET Core, Java, Ruby, Node.js, PHP, or Python. You can also run PowerShell and other scripts or executables as background services.

·         Managed production environment - App Service automatically patches and maintains the OS and language frameworks for you. Spend time writing great apps and let Azure worry about the platform.

·         DevOps optimization - Set up continuous integration and deployment with Azure DevOps, GitHub, BitBucket, Docker Hub, or Azure Container Registry. Promote updates through test and staging environments. Manage your apps in App Service by using Azure PowerShell or the cross-platform command-line interface (CLI).

·         Global scale with high availability - Scale up or out manually or automatically. Host your apps anywhere in Microsoft's global datacenter infrastructure, and the App Service SLA promises high availability.

·         Connections to SaaS platforms and on-premises data - Choose from more than 50 connectors for enterprise systems (such as SAP), SaaS services (such as Salesforce), and internet services (such as Facebook). Access on-premises data using Hybrid Connections and Azure Virtual Networks.

·         Security and compliance - App Service is ISO, SOC, and PCI compliant. Authenticate users with Azure Active Directory or with social login (Google, Facebook, Twitter, and Microsoft). Create IP address restrictions and manage service identities.

·         Application templates - Choose from an extensive list of application templates in the Azure Marketplace, such as WordPress, Joomla, and Drupal.

·         Visual Studio integration - Dedicated tools in Visual Studio streamline the work of creating, deploying, and debugging.

·         API and mobile features - App Service provides turn-key CORS support for RESTful API scenarios, and simplifies mobile app scenarios by enabling authentication, offline data sync, push notifications, and more.

·         Serverless code - Run a code snippet or script on-demand without having to explicitly provision or manage infrastructure, and pay only for the compute time your code actually uses (see Azure Functions).

 

How to Create Azure Functions

Ans: Azure Functions is a solution for executing small lines of code or functions in the cloud. We can also select the programming languages we want to use. We pay only for the time our code executes; that is, we pay per usage. It supports a variety of programming languages, like C#, F#, Node.js, Python, PHP or Java. It supports continuous deployment and integration. Azure Functions applications let us develop serverless applications.

What Is Azure Databricks? 

Ans: Azure Databricks is a fast, easy and collaborative Apache® Spark™ based analytics platform optimized for Azure. Designed in collaboration with the founders of Apache Spark, Azure Databricks combines the best of Databricks and Azure to help customers accelerate innovation with one-click setup; streamlined workflows and an interactive workspace that enables collaboration between data scientists, data engineers, and business analysts.  As an Azure service, customers automatically benefit from native integration with other Azure services such as Power BI, SQL Data Warehouse, Cosmos DB as well as from enterprise-grade Azure security, including Active Directory integration, compliance, and enterprise-grade SLAs.

What is Azure Advisor 

Ans: The Azure Advisor service provides information about your entire Azure landscape. It gives you a complete overview of your system needs including possible ways to save money.

·         High Availability shows you ways to improve the continuity of your business-critical applications.

·         Security detects threats and vulnerabilities that might lead to security breaches.

·         Performance shows you ways to speed up your applications.

·         Cost gives you ways to reduce your overall Azure spreading.

What is a cloud service role?

Ans: A cloud service role is comprised of application files and a configuration. A cloud service can have two types of roles.

What is the link to a resource?

Ans: To show your cloud service’s dependencies on other resources, such as an Azure SQL Database instance, you can “link” the resource to the cloud service. In the Preview Management Portal, you can view linked resources on the Linked Resources page, view their status on the dashboard, and scale a linked SQL Database instance along with the service roles on the Scale page. Linking a resource in this sense does not connect the resource to the application; you must configure the connections in the application code.

What is scale a cloud service?

Ans: A cloud service is scaled out by increasing the number of role instances (virtual machines) deployed for a role. A cloud service is scaled in by decreasing role instances. In the Preview Management Portal, you can also scale a linked SQL Database instance, by changing the SQL Database edition and the maximum database size, when you scale your service roles.

What is a web role?

Ans: A web role provides a dedicated Internet Information Services (IIS) web-server used for hosting front-end web applications.

What is a worker role?

Ans: Applications hosted within worker roles can run asynchronous, long-running or perpetual tasks independent of user interaction or input.

What is a role instance?

Ans: A role instance is a virtual machine on which the application code and role configuration run. A role can have multiple instances, defined in the service configuration file.

What is a guest operating system?

Ans: The guest operating system for a cloud service is the operating system installed on the role instances (virtual machines) on which your application code runs.

What is a cloud service component?

Ans: Three components are required in order to deploy an application as a cloud service in Azure:

What is deployment environments?

Ans: Azure offers two deployment environments for cloud services: a staging environment in which you can test your deployment before you promote it to the production environment. The two environments are distinguished only by the virtual IP addresses (VIPs) by which the cloud service is accessed. In the staging environment, the cloud service’s globally unique identifier (GUID) identifies it in URLs (GUID.cloudapp.net). In the production environment, the URL is based on the friendlier DNS prefix assigned to the cloud service (for example, myservice.cloudapp.net).

 What is a service definition file?

Ans: The cloud service definition file (.csdef) defines the service model, including the number of roles.

What is a service configuration file?

Ans: The cloud service configuration file (.cscfg) provides configuration settings for the cloud service and individual roles, including the number of role instances.

What is a service package?

Ans: The service package (.cspkg) contains the application code and the service definition file.

What is a cloud service deployment?

Ans: A cloud service deployment is an instance of a cloud service deployed to the Azure staging or production environment. You can maintain deployments in both staging and production.

What is Azure Diagnostics?

Ans: Azure Diagnostics is the API that enables you to collect diagnostic data from applications running in Azure. Azure Diagnostics must be enabled for cloud service roles in order for verbose monitoring to be turned on.

What is Azure Service Level Agreement (SLA)?

Ans: The Azure Compute SLA guarantees that, when you deploy two or more role instances for every role, access to your cloud service will be maintained at least 99.95 percent of the time. Also, detection and corrective action will be initiated 99.9 percent of the time when a role instance’s process is not running.

What is Cloud Computing?

Ans: Cloud computing is the use of computing resources (hardware and software) that are delivered
as a service over a network (typically the Internet).

What are the Service Model in Cloud Computing?

Ans: Cloud computing providers offer their services according to three fundamental models: Infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS) where IaaS is the most basic and each higher model abstracts from the details of the lower models.
Examples of IaaS include Amazon CloudFormation (and underlying services such as Amazon EC2), Rackspace Cloud, Terremark, Windows Azure Virtual Machines, Google Compute Engine. and Joyent.
Examples of PaaS include Amazon Elastic Beanstalk, Cloud Foundry, Heroku, Force.com, EngineYard, Mendix, Google App Engine, Windows Azure Compute, and OrangeScape.
Examples of SaaS include Google Apps, Microsoft Office 365, and Onlive. Source from.

What are the different cloud deployment models?

Ans: Cloud deployment models describe how cloud services are offered to users. The major deployment models associated with cloud computing are listed below:

Public cloud - Here, computing services are offered through third-party providers across the public internet and server.

Private cloud - Here, computing services are offered either over the private internal network or the internet only to the selected users.

Hybrid cloud - Here, the cloud computing environment combines both public cloud and private cloud, allowing to share data and applications between them.

Explain traffic manager benefits in Azure?

Ans. The major benefits offered by the traffic manager in Azure are:

·         Distribution of traffic based on several traffic-routing methods.

·         Continuous monitoring of endpoint health and automatic failover when endpoints fail.

What is a break-fix issue?

Ans. In Azure, break-fix issues are referred to as technical problems. It is an industry term used when “work involved in supporting a technology when it fails its normal course of action”. 

What is Azure Active Directory and how it is used?

Ans. Microsoft offers Azure active directory, a fully managed multi-tenant service that implements identity and access capabilities for applications running in Azure as well as applications operating in the on-premises environment. It is used for providing single sign-on and multi-factor authentication to help users from protecting attacks.

 What is an Availability Set?

Ans. Availability Set is a logical grouping capability majorly employed for separating VM sources from each other when they are deployed. They are used for building reliable cloud solutions. The VMs placed in the Availability set are run across various physical servers, storage units, compute racks, and network switches in Azure. If any failure occurs, only VMs subset is affected, and the overall solution stays operational. 

What is the use of a Lookup transformation?

Ans. Lookup transformation is used for performing lookups by combining data in input columns with columns in the reference dataset. The reference table can be a new table or an existing table, view, or the SQL result query result. 

Name the web application types that can be deployed with the Azure?

Ans. The web applications that can be deployed with the Azure are ASP.Net, PHP, and WCF.

Explain Azure Resource Manager?

Ans. Azure Resource Manager is used for provisioning management and deployment services in Azure. Management layer is used for updating and deleting resources in Azure subscription. You can organize related resources in resource groups and deploy your resources with JSON templates.

What is a Fault Domain?

Ans. A Fault domain represents the group of the underlying hardware that shares a common power source and network switch. Every fault domain comprises some racks and each contains a virtual machine. When you create virtual machines within an availability set, your virtual machines are automatically distributed across the fault domains in the Azure platform.

What are Update Domains?

Ans. The updated domain represents the group of the underlying hardware that can be rebooted or can withstand maintenance at the same time. When you create virtual machines within an availability set, your virtual machines are automatically distributed across the update domains by the Azure platform. This ensures that atleast one instance of your applications always remains working when the Azure platform is under periodic maintenance.

What is the difference between Azure Service Bus Queues and Storage Queues?

Ans. Two types of queue mechanisms are supported by Azure: Storage queues and Service Bus queues.

Storage queues: These are the part of the Azure storage infrastructure, features a simple REST-based GET/PUT/PEEK interface. Provides persistent and reliable messaging within and between services.

Service Bus queues: These are the part of a broader Azure messaging infrastructure that helps to queue as well as publish/subscribe, and more advanced integration patterns. 

Explain Azure Service Fabric.

Ans. Azure Service Fabric is a distributed platform designed by Microsoft to facilitate the development, deployment and management of highly scalable and customizable applications. The applications created in this environment consists of detached microservices that communicate with each other through service application programming interfaces.

Define the Azure Redis Cache.

Ans. Azure Redis Cache is an open-source and in-memory Redis cache that helps web applications to fetch data from a backend data source into cache and server web pages from the cache to enhance the application performance. It provides a powerful and secure way to cache the application’s data in the Azure cloud.

Explain the types of services you can build with the Service Fabric.

Ans. Majorly, two types of services you can build on Service Fabric:

·         Stateless Services - No state is stored in the service. The longer-term state is stored in an external database. This is the typical application/data layer approach to build services.

·         Stateful Services - The state is stored in the service. Allows the state to persist without the need for an external database.

What is the Windows Azure Platform?

Ans: A collective name of Microsoft’s Platform as a Service (PaaS) offering which provides a programming platform, a deployment vehicle, and a runtime environment of cloud computing hosted in Microsoft data centres.

What are the roles available in Windows Azure?

Ans: All three roles (web, worker, VM) are essentially Windows Server 2008. Web and Worker roles are nearly identical: With Web and Worker roles, the OS and related patches are taken care for you; you build your app’s components without having to manage a VM

What is the difference between the Windows Azure Platform and Windows Azure?

Ans: The former is Microsoft’s PaaS offering including Windows Azure, SQL Azure, and AppFabric; while the latter is part of the offering and Microsoft’s cloud OS.

What are the three main components of the Windows Azure Platform?

Ans:

1. Compute
2. Storage
3. AppFabric

What is Windows Azure compute emulator?

Ans: The compute emulator is a local emulator of Windows Azure that you can use to build and test your application before deploying it to Windows Azure.

What is fabric?

Ans: In the Windows Azure cloud fabric is nothing but a combination of many virtualized instances which run the client application

How many instances of a Role should be deployed to satisfy Azure SLA (service level agreement)? And what’s the benefit of Azure SLA?

Ans: TWO. And if we do so, the role would have external connectivity at least 99.95% of the time.

What are the options to manage session state in Windows Azure?  

 Ans:    

·         Windows Azure Caching

·         SQL Azure

·         Azure Table

What is cspack?

Ans: It is a command-line tool that generates a service package file (.cspkg) and prepares an application for deployment, either to Windows Azure or to the compute emulator.

What is csrun?

Ans: It is a command-line tool that deploys a packaged application to the Windows Azure compute emulator and manages the running service.

What is the guest OS?

Ans: It is the operating system that runs on the virtual machine that hosts an instance of a role.

How to programmatically scale-out Azure Worker Role instances?

Ans: Using AutoScaling Application Block

What is the difference between Public Cloud and Private Cloud?

Ans: Public cloud is used as a service via the Internet by the users, whereas a private cloud, as the name conveys is deployed within certain boundaries like firewall settings and is completely managed and monitored by the users working on it in an organization.

How to design applications to handle connection failure in Windows Azure?

Ans: The Transient Fault Handling Application Block supports various standard ways of generating the retry delay time interval, including fixed interval, incremental interval (the interval increases by a standard amount), and exponential back-off (the interval doubles with some random variation).

static RetryPolicy policy = new RetryPolicy(5, TimeSpan.FromSeconds(2),                TimeSpan.FromSeconds(2));                policy.ExecuteAction(() => { try { string federationCmdText = @”USE FEDERATION                Customer_Federation(ShardId =” + shardId + “) WITH RESET, FILTERING=ON”;                customerEntity.Connection.Open(); customerEntity.ExecuteStoreCommand(federationCmdText);                } catch (Exception e) { customerEntity.Connection.Close(); SqlConnection.ClearAllPools(); } });

What is Windows Azure Diagnostics?

Ans: Windows Azure Diagnostics enables you to collect diagnostic data from an application running in Windows Azure. You can use diagnostic data for debugging and troubleshooting, measuring performance, monitoring resource usage, traffic analysis and capacity planning, and auditing.

HTTP://WWW.WINDOWSAZURE.COM/EN-US/DEVELOP/NET/COMMON-TASKS/DIAGNOSTICS/

What is Blob?

Ans: BLOB stands for Binary Large Object. Blob is a file of any type and size.
The Azure Blob Storage offers two types of blobs –

1.       Block Blob

2.       Page Blob

URL format: Blobs are addressable using the following URL format:

What is the difference between Block Blob vs Page Blob?

Ans: Block blobs are comprised of blocks, each of which is identified by a block ID.
You create or modify a block blob by uploading a set of blocks and committing them by their block IDs.
If you are uploading a block blob that is no more than 64 MB in size, you can also upload it in its entirety with a single Put Blob operation. -Each block can be a maximum of 4 MB in size. The maximum size for a block blob in version 2009-09-19 is 200 GB or up to 50,000 blocks.
Page blobs are a collection of pages. A page is a range of data that is identified by its offset from the start of the blob. To create a page blob, you initialize the page blob by calling Put Blob and specifying its maximum size.
-The maximum size for a page blob is 1 TB. A page written to a page blob may be up to 1 TB in size.
what to use block blobs for streaming video. “The application must provide random read/write access” which is supported by Page Blobs

What is the difference between Windows Azure Queues and Windows Azure Service Bus Queues?

Ans: Windows Azure supports two types of queue mechanisms: Windows Azure Queues and Service Bus Queues.
Windows Azure Queues, which are part of the Windows Azure storage infrastructure, feature a simple REST-based Get/Put/Peek interface, providing reliable, persistent messaging within and between services.
Service Bus Queues are part of a broader Windows Azure messaging infrastructure dead-letters queuing as well as publish/subscribe, Web service remoting, and integration patterns.

HTTP://WCFPRO.WORDPRESS.COM/2010/12/06/COMMUNICATION-IN-WINDOWS-AZURE/ HTTP://MSDN.MICROSOFT.COM/EN-US/LIBRARY/WINDOWSAZURE/HH767287.ASPX

What is the dead letter queue?

Ans: 

1.       Messages are placed on the dead-letter sub-queue by the messaging system in the following scenarios.

2.       When a message expires and dead-lettering for expired messages is set to true in a queue or subscription.

3.       When the max delivery count for a message is exceeded on a queue or subscription.

4.       When a filter evaluation exception occurs in a subscription and dead-lettering is enabled on filter evaluation exceptions.

What is swap deployments?

Ans: To promote a deployment in the Azure staging environment to the production environment, you can “swap” the deployments by switching the VIPs by which the two deployments are accessed. After the deployment, the DNS name for the cloud service points to the deployment that had been in the staging environment.

What is minimal vs. verbose monitoring?

Ans: Minimal monitoring, which is configured by default for a cloud service, uses performance counters gathered from the host operating systems for role instances (virtual machines). Verbose monitoring gathers additional metrics based on performance data within the role instances to enable closer analysis of issues that occur during application processing. For more information

What are the instance sizes of Azure?

Ans: 

Windows Azure will handle the load balancing for all of the instances that are created. The VM sizes are as follows:
Compute Instance Size CPU Memory Instance Storage I/O Performance
Extra Small 1.0 GHz 768 MB 20 GB Low
Small 1.6 GHz 1.75 GB 225 GB Moderate
Medium 2 x 1.6 GHz 3.5 GB 490 GB High
Large 4 x 1.6 GHz 7 GB 1,000 GB High
Extra-large 8 x 1.6 GHz 14 GB 2,040 GB High

What is table storage in Windows Azure?

Ans: 

The Windows Azure Table storage service stores large amounts of structured data.
The service is a NoSQL datastore which accepts authenticated calls from inside and outside the Windows Azure cloud.
Windows Azure tables are ideal for storing structured, non-relational data
Table: A table is a collection of entities. Tables don’t enforce a schema on entities, which means a single table can contain entities that have different sets of properties. An account can contain many tables
Entity: An entity is a set of properties, similar to a database row. An entity can be up to 1MB in size.
Properties: A property is a name-value pair. Each entity can include up to 252 properties to store data. Each entity also has 3 system properties that specify a partition key, a row key, and a timestamp.
Entities with the same partition key can be queried more quickly, and inserted/updated in atomic operations. An entity’s row key is its unique identifier within a partition.