1. What Is Azure Cloud Service ? (Azure Interview Questions)
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.
Azure Interview Questions
2. What is Windows Azure Platform ?
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 datacenters.
3. What are Fault Domains ?
A fault domain is a logical group of underlying hardware that share a common power source and network switch, similar to a rack within an on-premise data-centers. As you create VMs within an availability set, the Azure platform automatically distributes your VMs across these fault domains. This approach limits the impact of potential physical hardware failures, network outages, or power interruptions.
4. What are Update Domains ?
An update domain is a logical group of underlying hardware that can undergo maintenance or can be rebooted at the same time. As you create VMs within an availability set, the Azure platform automatically distributes your VMs across these update domains. This approach ensures that at least one instance of your application always remains running as the Azure platform undergoes periodic maintenance. The order of update domains being rebooted may not proceed sequentially during planned maintenance, but only one update domain is rebooted at a time.
5. Why doesn’t Azure Redis Cache have an MSDN class library reference like some of the other Azure services ?
Microsoft Azure Redis Cache is based on the popular open source Redis Cache and can be accessed by a wide variety of Redis clients for many programming languages. Each client has its own API that makes calls to the Redis cache instance using Redis commands.
Because each client is different, there is not one centralized class reference on MSDN, and each client maintains its own reference documentation. In addition to the reference documentation, there are several tutorials showing how to get started with Azure Redis Cache using different languages and cache clients. To access these tutorials, see How to use Azure Redis Cache and click the desired language from the language switcher at the top of the article.
6. What is a Storage keys ?
Storage keys or Access Keys are used as an authentication mode for accessing the storage services account to manipulate information based on our requirements. In Windows Azure we have an option to provide a Primary Access Key and a Secondary Access Key, even though we will use a single access key to authenticate our application to the storage. The main reason to provide the secondary access key is to avoid downtime to the application. If we need to change the application access key by regenerating the access key it takes quite some time to take effect; this provides a downtime.
To avoid this type of situation, a secondary access key is provided so that if the primary needs to be changed or regenerated we can map the secondary temporarily to the storage and regenerate the primary. Let us see step by step of how to get the Access Keys using Windows Azure Management Portal.
7. What is the concept of the table in Windows Azure ?
Table is a one type of Azure Storage, where you can store your data as storage. Blobs are stored in container and Entity in table.
Following are the key concepts in table.
Tables allow structure data storage
There can be 0..n tables in a storage account
Table store data as a collection of entities
Entity have a primary key and properties as key value pair
8. What are the Storages in Windows Azure ?
Windows Azure data storage enables users to store, access, analyze and protect their data while making it available from anywhere and at any time. Windows Azure provides various services from storing data in SQL databases in the cloud for analysis and reporting to meet the needs of your business. Windows Azure ensures data security with high throughput of application data in the cloud. Windows Azure typically offers the following three types of storage in the cloud atmosphere.
BLOB: BLOBs offer a mechanism for storing large amounts of text or binary data, such as images, audio and visual files. It can scale up to 200 terabytes and can be accessed using REST APIs. We can move BLOB data as a single volume between private and public clouds using Windows Azure Drive.
Table: Tables represent storage locations across machines for data that reside in the form of entities and properties on the cloud. Tables store large amounts of unstructured data that can be accessed either using REST APIs from within a service running in Windows Azure or directly over the Internet using HTTP/HTTPS.
Queue: The sole objective of a Queue is to enable communication between Web and Worker Role instances. They aid in storing messages that may be accessed by a client. Web Role instances can initiate user requests that need to be processed in the background. On the other side a Worker Role observers the queue to process the request and respond back via queue to the Web Role instance.
Azure Interview Questions
9. What is a web role ?
A web role provides a dedicated Internet Information Services (IIS) web-server used for hosting front-end web applications.
10. What is the difference between Block Blob vs Page Blob ?
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.
11. What is the difference between Windows Azure Queues and Windows Azure Service Bus Queues ?
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 that supports queuing as well as publish/subscribe, Web service remoting, and integration patterns.
12. Why was my client disconnected from the cache ?
The following are some common reason for a cache disconnect.
The client application was redeployed.
The client application performed a scaling operation.
In the case of Cloud Services or Web Apps, this may be due to auto-scaling.
The networking layer on the client side changed.
Transient errors occurred in the client or in the network nodes between the client and the server.
The bandwidth threshold limits were reached.
CPU bound operations took too long to complete.
On the standard cache offering, the Azure Redis Cache service initiated a fail-over from the primary node to the secondary node.
Azure was patching the instance where the cache was deployed
This can be for Redis server updates or general VM maintenance.
13. What Are The Service Model In Cloud Computing ?
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.
14. What Is A Cloud Service Role ?
A cloud service role is comprised of application files and a configuration. A cloud service can have two types of role.
15. What is a service configuration file ?
The cloud service configuration file (.cscfg) provides configuration settings for the cloud service and individual roles, including the number of role instances.
16. What is Azure Redis Cache ?
Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker. Azure Redis Cache is based on the popular open-source Redis cache. It gives you access to a secure, dedicated Redis cache, managed by Microsoft, and accessible from any application within Azure. It supports data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs and geospatial indexes with radius queries.
Apart from this Azure Interview Questions Blog, if you want to get trained from professionals on this technology.
Azure Interview Questions
17. What is the Service Model in Cloud Computing ?
This is the service model on which you will host your application(s), for example IaaS, PaaS or SaaS. Each of these service models requires various levels of support and responsibilities once a system is deployed to the platform. To resolve the future challenges that you might encounter you need to understand the models carefully. Other than the service model, the second, you need to decide whether you want a Private or On-Premise cloud, or you want your application to be deployed on a Public Cloud.
Every service model offers you some kind of resource required to operate the most web-enabled systems imaginable.
18. What are Redis databases ?
Redis Databases are just a logical separation of data within the same Redis instance. The cache memory is shared between all the databases and actual memory consumption of a given database depends on the keys/values stored in that database. For example, a C6 cache has 53 GB of memory. You can choose to put all 53 GB into one database or you can split it up between multiple databases.
19. What is Azure Service Level Agreement (SLA) ?
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.
20. What are the data synchronize services in Azure ?
Sync Services is provided by Microsoft Azure where you can keep a SQL Azure database synchronized with another database. You can take a backup of a database from one region to another region. There is a simple procedure you need to follow to configure this service. If not a complete database then you can at least keep selected tables or selected rows of tables synchronized.
This service provides the following two ways to synchronize:
Synchronize a SQL Azure database from one SQL Azure server to another SQL Azure server.
Synchronize a SQL Azure Database from an Azure Server to a Local Server database.
21. Is it possible to create a Virtual Machine using Azure Resource Manager in a Virtual Network that was created using classic deployment?
This is not supported. You cannot use Azure Resource Manager to deploy a virtual machine into a virtual network that was created using classic deployment.
22. What is the Windows Azure Platform ?
The Windows Azure Platform lays the foundation for running applications and keeping data on the cloud. It contains computer services, storage services and the fabric. Windows Azure affords a wide range of capabilities in the form of computing services to run applications, storage services and creating a framework that supports several applications, as well as host services and manage them centrally. This platform readily stipulates an internet infrastructure for deploying distributed applications and services since we can develop a cloud service in Visual Studio .NET and deploy it into the Azure cloud right from on-premise tools. The Azure platform is a group of three cloud technologies as in the following:
Windows Azure Platform
23. What Is Minimal Vs. Verbose Monitoring ?
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.
24. Difference between Web and Worker Roles in Windows Azure ?
The main difference between the two is that an instance of a web role runs IIS, while an instance of a worker role does not. Both are managed in the same way, however, and it’s common for an application to use both.For example, a web role instance might accept requests from users, then pass them to a worker role instance for processing.
Azure Interview Questions
25. What is Windows Azure and explain its services ?
Windows Azure is created by Microsoft, it is a cloud computing infrastructure and platform. It is designed for working on the global network of Microsoft. It is for building, managing and deploying services and applications. Windows Azure supports various programming languages, tools, and frameworks. It can be included in both Microsoft specific and third party systems and software. It provides an infrastructure of services and platforms as services. It is also an open and flexible cloud platform that makes it easy to work on the global network. It helps us to quickly create, manage and deploy applications on the global network.
Features of Windows Azure
Windows Azure runs and stores the data on Microsoft datacenters. There are many features that are specified here:
Websites allows the developers to build the sites using ASP.NET, PHP, etc and deploy these websites using FTP, Git etc.
SQL Database, formally known as Azure database creates, extends and scales the application into the cloud using Microsoft SQL Server.
This is Microsoft’s platform as a service that supports the Multi-tier applications and automated deployment.
Windows Azure Services
There are various types of services that are provided by Windows Azure:
Windows Azure Services
26. What Is Swap Deployments ?
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.
27. What is Auto Scaling ?
Scaling by adding additional instances is often referred to as scaling out. Windows Azure also supports scaling up by using larger role instances instead of more role instances.
By adding and removing role instances to your Windows Azure application while it is running, you can balance the performance of the application against its running costs.
An autoscaling solution reduces the amount of manual work involved in dynamically scaling an application.
28. what is VM role in Windows Azure ?
Virtual Machine (VM) roles, now in Beta, enable you to deploy a custom Windows Server 2008 R2 (Enterprise or Standard) image to Windows Azure. You can use the VM role when your application requires a large number of server OS customizations and cannot be automated. The VM Role gives you full control over your application environment and lets you migrate existing applications to the cloud.
29. What happens when you exhaust the maximum failed attempts for authenticating yourself via Azure AD ?
We use a more sophisticated strategy to lock accounts. This is based on the IP address of the request and the passwords entered. The duration of the lockout also increases based on the likelihood that it is an attack.
30. Where can I find a list of applications that are pre-integrated with Azure AD and their capabilities ?
Azure AD has around 2600 pre-integrated applications. All pre-integrated applications support single sign-on (SSO). SSO let you use your organizational credentials to access your apps. Some of the applications also support automated provisioning and de-provisioning.
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31. What are the differences between Subscription Administrator and Directory Administrator ?
By default, one is assigned the Subscription Administrator role when he/she signs up for Azure. A subscription admin can use either a Microsoft account or a work or school account from the directory that the Azure subscription is associated with. This role is authorized to manage services in the Azure portal. If others need to sign in and access services by using the same subscription, you can add them as co-admins.
Azure AD has a different set of admin roles to manage the directory and identity-related features. These admins will have access to various features in the Azure portal or the Azure classic portal. The admin’s role determines what they can do, like create or edit users, assign administrative roles to others, reset user passwords, manage user licenses, or manage domains.
32. What is the difference between Service Bus Queues and Storage Queues ?
The Azure Storage Queue is simple and the developer experience is quite good. It uses the local Azure Storage Emulator and debugging is made quite easy. The tooling for Azure Storage Queues allows you to easily peek at the top 32 messages and if the messages are in XML or Json, you’re able to visualize their contents directly from Visual Studio Furthermore, these queues can be purged of their contents, which is especially useful during development and QA efforts.
The Azure Service Bus Queues are evolved and surrounded by many useful mechanisms that make it enterprise worthy! They are built into the Service Bus and are able to forward messages to other Queues and Topics. They have a built-in dead-letter queue and messages have a time to live that you control, hence messages don’t automatically disappear after 7 days.
Furthermore, Azure Service Bus Queues have the ability of deleting themselves after a configurable amount of idle time. This feature is very practical when you create Queues for each user, because if a user hasn’t interacted with a Queue for the past month, it automatically gets clean it up. Its also a great way to drive costs down. You shouldn’t have to pay for storage that you don’t need. These Queues are limited to a maximum of 80gb. Once you’ve reached this limit your application will start receiving exceptions.
Azure Interview Questions
33. What Is A Cloud Service Deployment ?
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.
34. What Is Azure Diagnostics ?
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. For more information.
35. What is Diagnostics in Windows Azure ?
Windows Azure diagnostics provides facility to store diagnostics data. Some diagnostics data is stored in a table, while some is stored in a blob. For collecting diagnostics data, we must initialize the Windows Azure diagnostic monitor. The Windows Azure diagnostic monitor runs in Windows Azure and in the computer’s emulator and collects diagnostic data for a role instance.
Following diagnostics data is stored in table storage:
Data Source Table name in Azure Storage Detail
Windows Azure Logs WADLogsTable These are the application logs dumped from the application.
Windows Azure Diagnostics Infrastructure Logs WADDiagnosticInfrastructureLogsTable These are the logs about running of diagnostics service.
Windows Event logs WADWindowsEventLogsTable These are the logs generated on the instance where logs are running.
Performance counters WADPerformanceCountersTable These are the performance matrices like memory utilization, processor utilization, response time etc.
Following diagnostics data is stored in blob storage:
Data Source Container name in azure storage Detail
IIS Logs wad-iis-logfiles These are the IIS logs generated by role instances.
Failed Request Logs wad-iis-failedreqlogfiles These are the IIS failed requests logs generated by role instances.
Crash Dumps wad-crash-dumps These are the logs generated on the application crash.
36. What is Azure Queues ?
The main reason for using queues is to provide loose connectivity among various components. For example, we have two components of an application to exchange data. Here one of them is on-premise and one exists in the cloud. Here if we use a web service to exchange data we have the following issues:
Both components should be online simultaneously; if one partner is down, then the communication will not work.
It’s difficult to scale up if more work is present.
In Azure Queues you have a queue as mediator that connects the two components, so when the receiver is down, the sender can still insert messages into the queue, once a receiver comes online it can receive message from that queue. And for scale up we just need to add more receivers and your queue is processed in parallel.
The following are the drawbacks of using a queue:
Queues has some charges, however these are minimal.
Your queue is doing mediator work here. If your queue is down, devices will not able to communicate with each other.
37. How can you create a Queue in storage account ?
Queue is a one type of Azure Storage, where you can store your data as storage. Blobs are stored in container, Entity in table and Message in Queue.
Following are the key concepts in queue.
Messages are added to end of the Queue and processed from the front
Queues provides a good way of Front end and Back end decoupling
In the real world example the user can queue a job through the web role (front end) and the job can be processed by a worker role (back end). This gives an opportunity to decouple the web role and worker role.
Place a new label control on the aspx page and add the following code in the page load event.
protected void Page_Load(object sender, EventArgs e)
StorageCredentialsAccountAndKey accountAndKey = newStorageCredentialsAccountAndKey(“account”, “key”);
CloudStorageAccount account = new CloudStorageAccount(accountAndKey, true);
CloudQueueClient client = account.CreateCloudQueueClient();
CloudQueue queue = client.GetQueueReference(“workitems”);
CloudQueueMessage message = new CloudQueueMessage(“Test Work Item”);
// Populate the messages
message = queue.GetMessage();
if (message != null) Label1.Text = “Message in Queue: ” + message.AsString;
Azure Interview Questions
38. What is Azure Search ?
Azure Search is a cloud search-as-a-service solution that delegates server and infrastructure management to Microsoft, leaving you with a ready-to-use service that you can populate with your data and then use to add search to your web or mobile application. Azure Search allows you to easily add a robust search experience to your applications using a simple REST API or .NET SDK without managing search infrastructure or becoming an expert in search.
39. What is Windows Azure Portal and also explain the Azure Fabric ?
Windows Azure Portal:To run an application, a developer accesses the Windows Azure portal through her Web browser, signing in with a Windows Live ID. She then chooses whether to create a hosting account for running applications, a storage account for storing data, or both.
Once the developer has a hosting account, the developer can use a Windows Azure portal to submit applications to Windows Azure.
When the user sends a request to an application hosted on Azure (that can be passed by protocols like HTTP, HTTPS or TCP), the request will be received from the load balancer. The Load balancer balances the load across all the instances of the role (Web, Worker, and VM).
The Azure fabric is the main core concept over here. It provides a service called the Azure Fabric Controller. It is called as OS for the Azure. Because it handles/manages:
All roles (computing) and resources.
Deployment and activating services.
Health monitoring for all services.
Allocating, releasing of resources.
Provisioning VM, terminating etc.
Updating patches for installed OS on VM automatically.
So there would be better to have two instances of roles and also no need to worry about software updates for user.
40. What are virtual machine scale sets in Azure ?
Virtual machine scale sets are Azure compute resource that you can use to deploy and manage a set of identical VMs. With all the VMs configured the same, scale sets are designed to support true autoscale, and no pre-provisioning of VMs is required. So it’s easier to build large-scale services that target big compute, big data, and containerized workloads.
Azure Interview Questions
41. What is cspack ?
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.
42. What is Azure HD Insight ?
Azure HDInsight deploys and provisions Apache Hadoop clusters in the cloud, providing a software framework designed to manage, analyze, and report on big data.
With the September 2015 release of HDInsight, now customers configure these clusters to run using both a Windows Server Operating System as well as an Ubuntu based Linux Operating System.
HDInsight on Linux enables even broader support for Hadoop ecosystem users to run in HDInsight providing you even greater choice of preferred tools and applications for running Hadoop workloads.
Both Linux and Windows clusters in HDInsight are built on the same standard Hadoop distribution and offer the same set of rich capabilities.
43. What Is Scale A Cloud Service ?
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.
44. What is TFS build system in Azure ?
A Build is nothing but the output of a solution. In the case of Azure projects, you generally get the file with a .cspkg extension that means a Cloud Service Package is used for the deployment of your cloud services.
In layman’s terms a build server acts as the machine where you put your deployment packages.
To use Team Foundation Build, you must have at least one build machine. This machine can be a physical machine or a virtual machine.
Build Controllers are the element in the build system that accepts the build requests from any project inside the team project collection. Each build controller is dedicated to a single-team project collection. So there is a one-to-one relationship between a team project collection and a build controller.
Build agents are elements in the build system that does more processor-intensive work.
A Build definition is nothing but the process that the build controller using to deploy your packages to a target site. Using Team Explorer you should be able to create a new build definition where you will need to associate the build controller and define process as well as trigger a point for the definition.
Once the build definition is in place, you will be able to queue new builds using it.
Typical Build System Topology
45. What are the password requirements when creating a VM ?
Passwords must be 12 – 123 characters in length and meet 3 out of the following 4 complexity requirements:
Have lower characters
Have upper characters
Have a digit
Have a special character (Regex match [\W_])
46. What is AWS Cloud Formation ?
AWS Cloud Formation is a cloud builder service that helps you model and set up your Amazon Web Services resources so that you can spend less time managing those resources and more time focusing on your applications that run in AWS. For this you need to create a template that describes all the AWS resources that you want, like Amazon EC2 instances that you want, Amazon VPC and subnet details and so on. AWS CloudFormation takes care of provisioning and configuring those resources for you. You don’t need to individually create and configure AWS resources and figure out what’s dependent on what, AWS CloudFormation handles all of that.
AWS CloudFormation is available at no additional charge. You will be billed only the normal rates for the AWS resources like EC2, RDS, LB and so on that AWS CloudFormation creates and your application and resources use.
47. What is the meaning of application partitions ?
The application partitions are a part of the Active Directory system and having said so, they are directory partitions which are replicated to domain controllers. Usually, domain controllers that are included in the process of directory partitions hold a replica of that directory partition. The attributes and values of application partitions is that you can replicated them to any specific domain controller in a forest, meaning that it could lessen replication traffic. While the domain directory partitions transfer all their data to all of the domains, the application partitions can focus on only one in the domain area. This makes application partitions redundant and more available.
48. What is WordPress in Microsoft Azure ?
WordPress is Web software you can use to create a Web sites, blog, or apps. The core software is built by hundreds of community volunteers, and when you’re ready for more, there are thousands of plugins and themes available to transform your site into almost anything you can imagine.
We can install WordPress on our local computers to develop Web sites, blogs, or theme plugins; or we can install it on the cloud where everyone can access our Web sites.
Installing and Running WordPress.
Login to manage.windowsazure.com to access you Azure portal.
Click on CREATE A WEB APP or +NEW button in the portal.
You can select QUICK CREATE and then upload it from your computer.
On clicking Gallery the model window will appear where you can find WordPress by scrolling (or navigating to BLOGS, then WordPress).
Select the WordPress and click next. Fill the required Information.
Fill the URL, database, region and deployment setting details.
Click on Next: Fill in information about MySQL database. Azure will choose the unique name of your database and region to place the database physically.