Having worked as a cloud and DevOps professional for over a decade I had the pleasure of attending the interviews as a candidate as well as on the interview panel. And the best advice to someone who is preparing for azure interview would be to make sure you have a good hands-on experience and a clear understanding of the workflow.
Microsoft provides a 30-day free Azure trial which can be used as a playground for a real-time experience. You can check out my previous article here to find out how you can create a free Azure subscription with a premium azure active directory license. Most of the articles or videos about Azure Interview Questions I have seen on the internet talk about the theoretical questions which nobody asks.
I will try to list down a few questions which can be used to test the logical understanding of Azure components. Every interviewer has his/her way of judging the candidates, which means most of the interviews will have different questions, but if you familiarize yourself with these concepts you should be in a position to answer most of the questions.
Compute, I usually start with the computing questions, because this is one section where everyone should be really comfortable.
Scenario: I start with a question to check candidate’s logical thinking.
My team works on an application which is installed on Azure Virtual machine. And the team reports unresponsive application for 2-3 hours a day, unfortunately this window isn’t consistent and they don’t see a pattern. How would you approach this scenario?
Que: If you are working on a VM which faces performance issues often. How will you troubleshoot this?
Ans: In this scenario you should start with the Azure monitor and check the metrics history, which will give you good amount of data to begin with. If this still doesn’t help, we can login to the VM and check the server logs such as event viewer in windows or system logs in Linux. If that also doesn’t help we can check the application logs and figure out the issue. But based on my experience performance issues are usually caused because of deadlocks or insufficient resources such as CPU or Memory.
Que: Okay, if you have identified it is because of high CPU utilization, how would you approach here?
Ans: Please note, this is a random behavior and team faces performance issue intermittently so instead of just resizing we can use Virtual machine scale sets (VMSS). This will ensure we only use compute resources as and when required.
Que: What is Virtual Machine scale sets?
Ans: Azure virtual machine scale sets let you create and manage a group of load balanced VMs. The number of VM instances can automatically increase or decrease in response to demand or a defined schedule. Read this article to know more.
Que: What is availability set and availability zone?
Ans: 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. Azure availability zones are physically separate locations within each Azure region that are tolerant to local failures. Failures can range from software and hardware failures to events such as earthquakes, floods, and fires. Check this link to know more.
Que: What is Trusted Launch Virtual Machine?
Ans: Check out this link to know more.
Que: My team plans to resize a disk attached to virtual machine. Can I do that on the fly? And what is the procedure for that?
Ans: It depends on what action you are performing. Ideally we can’t resize any disk without downtime. But recently Microsoft started supporting data disk expansion without downtime, we still can’t expand OS disk without any downtime, you can use this link to read more about it.
Que: What is Proximity placement group?
Ans: A proximity placement group is a logical grouping used to make sure that Azure compute resources are physically located close to each other. Proximity placement groups (PPG) are useful for workloads where low latency is a requirement. Check this link to know more about it.
Que: What is Azure Dedicated host?
Ans: Azure Dedicated Host is a service that provides physical servers – able to host one or more virtual machines – dedicated to one Azure subscription. Dedicated hosts are the same physical servers used in Azure data centers, provided as a resource. Use this link to know more.
Que: If you have answered the availability zones question correctly, the interviewer might also ask about fault and update domain.
Ans: Check this link to know your answer.
Que: What is Guest agent in Azure Virtual machine? And what is the role of extensions.
Ans: Check this link to know more about guest agent.
Que: My application is hosted on a Virtual machine and I want to make it resilient. What options do you have to ensure my server is prone to any downtime and my applications can withstand any disaster?
Ans: Hosting your application on a single virtual machine isn’t a good idea if resiliency is your target. I would recommend using Azure Virtual Machine Scale Sets to ensure your infrastructure is capable of autoscaling based on the load. Azure also provides an option to use Availability set and Availability zones for high availability as explained earlier.
Que: In our project we are majorly using Azure Virtual machines and we want to ensure our VMs are prone to any disaster. What different backup and restore options can you suggest for our Virtual Machines?
Ans: Please check this link for your answer.
Que: I want to backup my virtual machine which is in EastUS using the recovery services vault which is in WestUS since this is the vault being used for backing up all my virtual machines. I am trying to discover the machine but can’t find it. What is the issue?
Ans: Vault will only list VMs from same region as the vault and VMs which aren’t already backed up by any other vault.
Que: Difference between Azure Migrate and Azure Site Recovery?
Ans: Check this link to know more about it.
Que: While working on a server my team had a requirement to add a new disk on a windows virtual machine. We added a new disk on the VM. When we login to the Virtual machine and open the windows explorer, we can’t see the newly added disk there. What can be the issue?
Ans: When you add a new disk from portal on windows virtual machine, you have to ensure this reflects in the disk management as well. So as part of the process you should login to the virtual machine, open the disk management using “diskmgmt.msc” and scan for any new disk. Follow the steps that you see on that user interface.
Que: My requirement is to setup an application on a Virtual Machine. And I would like to ensure this is a secure setup. How will you ensure I follow best practices?
Ans: When we talk about security, there are two basic principals: Least privilege and Least network access.
* To ensure security, we should make sure only authorized people are allowed to access the virtual machine. For example, people should only have read permissions wherever possible, and write or execute permission should be allowed only when required.
* We should try and eliminate the public access, if possible disable public IP and use only private IPs to connect to this machine.
* Block required ports. Only allow communication on required ports.
Que: Okay, if my virtual machine doesn’t have a public IP, how can I connect and login to this Virtual machine.
Ans: To connect to a virtual machine without public IP we can use:
* Bastion service.
* Connect using VPN
* Configure Just in time access
* If both the options aren’t possible, create a new server with public IP in same VNET. This server will be used as a jump server and since these both machines are on same network you can eventually connect to our main server using private IP. (Please note this is not advised, I strictly advise against using any public IP)
Que: Which Virtual machine series have you used mostly in your experience and why? People can use series, size or SKUs as an alternate term for this.
Ans: Majorly used series are B series (in case of Dev and Test), D series for general purpose. I have also seen people use E series for memory extensive application. F series virtual machines are preferred for compute optimized workloads. I have also seen teams using N series VM where GPU based computing is required, this is primarily used as part of ML inference clusters. You can check this link to know more in detail.
Que: What is Azure Spot Virtual Machines?
Ans: Using Azure Spot Virtual Machines allows you to take advantage of our unused capacity at a significant cost savings. At any point in time when Azure needs the capacity back, the Azure infrastructure will evict Azure Spot Virtual Machines. Therefore, Azure Spot Virtual Machines are great for workloads that can handle interruptions like batch processing jobs, dev/test environments, large compute workloads, and more.