This tutorial provides frequently asked VMware interview questions and answers with explanations to help you prepare for the interview:
We all know that VMware dominates the virtualization market and currently, VMware has an 80% market share, IBM 5.3% and the rest of vendors have 13.9%.
In this article, you will find a list of top interview questions and answers about VMware technology. These questions are drafted, taking into consideration point-to-point answers expected in MNC companies instead of explaining them in detail.
These VMware questions and answers will be useful for freshers, junior technicians, Vmware administrators, virtualization consultants, support Engineers, solution architects, or any IT administrator preparing for the interview.
This insightful post covers top sections of VMware like basic questions, migration, troubleshooting, cloning, ESXI server, host, clusters, VMotion, VMware DRS (distributed resource scheduler) and HA (high availability), networking and storage architecture, virtual center management server, VMware backups, administration of virtual network, VMware security, etc.
So let’s start!
Best VMware Interview Questions and Answers
Q #1) What do you know about VMware?
Answer: VMware was the first commercial company to introduce the x86 virtualization architecture in 1999. It is an American company that was founded in California in 1998 and started building virtualization platforms. In 2004, EMC acquired VMware, and subsequent Dell technologies acquired EMC.
The desktop version of VMware supports a variety of operating systems such as Microsoft Windows, Linux, and macOS, while the enterprise server version, known as VMware ESXi, runs directly on the server hardware without the need for an additional operating system.
Q #2) Why do you choose a VM over a physical system?
Answer: Most IT organizations have high-end physical servers and systems, but their use is minimal, and this leads to higher operating costs and higher physical space requirements. To solve these and other problems, IT infrastructure virtualization is used.
The top 5 reasons to replace physical systems with virtual systems are:
- It lowers IT costs.
- Functions such as fault tolerance reduce downtime to almost zero.
- High probability of faster provisioning of systems and servers.
- Improved data security.
- Portability and increased efficiency of hardware and software resources.
Q #3) Which different IT platforms can be virtualized or what types of virtualization are there?
Answer: The virtualization revolution has made almost all IT infrastructure virtual. Below are the 5 main types of virtualization:
- Desktop virtualization: Also called VDI, creates virtual versions of each desktop and operating system (OS). It allows users to access the desktop from anywhere and from any device.
- Storage virtualization: It combines multiple physical storages into a single virtual storage device. Physical storage can come from different locations and from different providers. All of these physical repositories are aggregated, viewed, and managed by a single storage virtualization console.
- Server virtualization: High-end physical servers are divided into multiple logical virtual servers, and the hardware resources of one physical server can be shared among many virtual servers. The main advantage is that each virtual server is allowed to run a different operating system. In addition, companies reduce their huge hardware footprint.
- Network virtualization: It is a method for combining various physical network resources such as switching, routing, firewall, load balancing, a virtual private network (VPN) on a virtual platform. It allows administrators to manage entire network platforms from a single virtual console. This helps reduce operational difficulties, scale easily, and improve network security.
- Application virtualization: With application virtualization, applications are installed and run on virtual servers and can be accessed from anywhere and from any device. One of the main advantages of application virtualization is that any type of application can be accessed from any system without supporting standard operating systems and hardware.
Q #4) What is VMware vSphere?
Answer: VMware vSphere is a suite of four VMware virtualization products.
- ESXi: Previously known as ESX. It is a bare-metal hypervisor installed on a server that divides a physical server into multiple virtual machines.
- vCenter Server: This is a centralized platform for managing the entire vSphere visibility and management environment. IT administrators or virtual machine administrators use this console to manage the entire virtual environment.
- vSphere Client: The vSphere client acts as an administrative interface to access VMware hosts. These hosts running VMware ESXi are servers running individual virtual machines (VMs). The VSphere client connects to the host server. Administrators can use this interface to create and manage virtual machines and host resources.
- vMotion: Enables live migration of virtual machines from one physical server (host) to another with continuous service availability with no downtime.
=>> Click here for an in-depth explanation.
Q #5) What is NFS (Network File system)?
Answer: NFS is a client/server protocol developed by Sun Microsystems in 1984 for NAS (network access storage). This allows clients to view, save, and update files on remote computers as if they were stored locally. In VMware, NFS is used by ESXi hosts to communicate with NAS over a TCP/IP network.
Q #6) What is the difference between VMware and Microsoft Hyper-V and which one do you prefer and why?
Answer: VMWare and Hyper-V have their respective strengths and weaknesses, but the final call for deployment depends entirely on IT infrastructure requirements.
Let’s take a look at some of the basic differences between them:
- Storage: The VMware Virtual Machine File System (VMFS) has a slight advantage over the Hyper-V file system (ReFS) which is persistent on the cluster. VMFS is easier to use than ReFS.
- Snapshots: VMware allows 32 snapshots, while Hyper-V allows 64. Snapshots allow a copy to be stored in a virtual machine for use in the event of data loss.
- Memory management: VMware uses techniques such as memory compression, transparent paging, and overwrite/overwrite, whereas Hyper-V uses only dynamic memory.
- Operating System Support: VMware supports Windows, Linux, Unix, and macOS, while Hyper-V supports Windows, Linux, and FreeBSD.
- Scalability: It uses more logical processors and virtual processors per host, while Hyper-V can accommodate more physical storage per host and virtual machine.
- Security: VMware enforces data encryption at rest, on the move, and even during migration, while Hyper-V is managed via Active Directory with built-in protection.
- Pricing: VMware costs per processor, while Hyper-V pricing is based on the number of cores per host.
=>> Click here for detailed information about Microsoft Hyper-V
Q #7) What is a .vmdk file?
Answer: .vmdk is a hard disk file format developed by VMware for virtual machines. This virtual hard disk format has a .vmdk file extension and is used by VMware and VirtualBox virtual machines. The vmdk file stores information about the partitions that the virtual machine can access.
Q #8) What is a hypervisor?
Answer: A hypervisor is a software that creates and runs virtual machines. A hypervisor allows a single host computer to support multiple virtual machines and effectively share their resources, such as memory and processing.
Multiple virtual machines can run on a single physical server with a hypervisor. Because of hypervisor, the system resources ensure greater IT flexibility. As virtual machines are independent of the host hardware, this makes them easily move between different servers.
Click here for more like how it works, the difference between container and hypervisor, benefits, etc.
Q #9) What types of hypervisors are there and which one is better?
Answer: There are basically two types of hypervisors:
- Bare Metals (Type 1): Works directly on the host hardware.
- Hosted (Type 2): It runs as a software layer on an operating system.
Bare metal hypervisors are widespread because they are installed directly on the hardware, isolating them from malware and other attacks because they are far from the operating system. In addition, they tend to perform better and more efficiently than a hosted hypervisor.
Q #10) What is RDM and how many compatibility modes does it have?
Answer: Raw Device Mapping (RDM) is a VMware virtualization technology that allows virtual machines to access LUNs (logical unit numbers) directly from the SAN, which makes it possible to format the LUN with any file system.
RDM can be used for configurations that involve clustering between virtual machines, between physical and virtual machines, or where SAN-enabled applications run on virtual machines.
RDM has two compatibility modes:
- Physical Compatibility Mode: Allows RDM to behave exactly like virtual disk files, including the use of snapshots.
- Virtual Compatibility Mode: Allows direct access to SCSI devices for applications that require less control.
Click here to know how exactly it works.
Q #11) What hardware version is used in VMware ESXi 5.5?
Answer: At the point when you make a virtual machine or upgrade a current virtual machine, utilize the virtual machine similarity settings to choose the ESXi to have an adaptation that the virtual machine can run.
Virtual equipment incorporates BIOS and EFI, accessible virtual PCI openings, the most extreme number of processors, the greatest memory setup, and different capacities.
New virtual equipment highlights are ordinarily delivered once per year with a significant or minor rendition of vSphere. The accompanying table shows that VMware have renditions and viable hardware versions
|VMware host versions||Virtual hardware versions|
|ESXi 7.0 Update 2 and later||hardware version 19|
|ESXi 7.0 Update 1 and later||hardware version 18|
|ESXi 7.0 and later||hardware version 17|
|ESXi 6.7 Update 2 and later||hardware version 15|
|ESXi 6.7 and later||hardware version 14|
|ESXi 6.5 and later||hardware version 13|
|ESXi 6.0 and later||hardware version 11|
|ESXi 5.5 and later||hardware version 10|
Q #12) What is the difference between the vSphere ESX and ESXi architectures?
Answer: VMware ESXi is the latest hypervisor architecture from VMware. The main difference between the two is packaging architecture and operational management. The ESXi architecture has a very thin footprint regardless of the operating system, which makes it secure and robust.
Q #13) What is VMware VMotion used for and what conditions are required for VMotion to run?
Answer: Vmotion is VMware’s tool that allows you to migrate VMs from one host to another without any downtime. Several prerequisites must be met before VMotion can run successfully, like.
- Requires access to network privileges such as access to data stores, network connectivity, and so on.
- The processor architecture must be compatible between the two hosts.
- Requires at least a gigabit network connection
- VM kernel port must be enabled
Q #14) How do the terms clone and template differ from each other in VMware?
Answer: Templates act as source images for virtual machines with enterprise standard configurations, whereas cloning in VMware is the process of creating exact copies of virtual machines with the same configuration, settings, files, and applications without modification.
The following table shows the exact differences between them:
|It is created when the VM is ON||It is created when the VM is OFF|
|It is the complete copy of the VM.||It is a master copy of a VM that is used to create many clones.|
|Cloned VM can be powered off and on.||You cannot power on/off or edit a template.|
|Clone VMs are best suited for Tests or DR environments.||The template is good for bulk deployment|
|Once clone is created it cannot be converted back to VM||It is possible to convert the template back to VM and again convert back to template|
Q #15) What is the purpose of VMware DRS and point out its few advantages.
Answer: The main purpose of DRS (Distributed Resource Scheduler) is to balance the load and resources in a group of clustered ESXi hosts.
If a particular ESXi host is loaded with multiple virtual machines, it is very likely that the host will perform poorly in such a scenario, DRS migrates virtual machines to other hosts in the cluster to maximize performance.
The main advantages of DRS are
- Balanced Capacity
- Reduced Energy Consumption
- Initial Workload Placement
- Automated Load Balancing
- Optimized Power Consumption
- Cluster Maintenance
- Constraint Correction
The above information about DRS is brief. Click here to know its working and other benefits.
Q #16) VMware Snapshot is a quick and easy way to restore data, but it’s not a backup. Can you explain?
Answer: Snapshot of the VM is taken at the present point of time and consists of files, software, and settings, while backups can be performed or scheduled at any time and consist of only data.
The exact difference between VMware snapshot and backup can be easily seen in the following table:
|VMware snap shot||Backup|
|It is a picture of the VM at the present point of time.||Backup may have differences based on when it is initiated|
|It has to be restored at the same location||It can be restored at same as well as different location|
|It take very less time to copy and restore||Backup and Restoration usually depends on the size of the data but generally it takes longer time then snap shot.|
|Snapshots don’t take much space||Backup takes space based on size of the data|
|It allows much frequent protection then backup because it can be taken every minutes or hour||They need to be scheduled once in a day and need to be process during off hours|
Q #17) What are VMware HA (high availability) and FT (Fault tolerance)?
Answer: Fault Tolerance (FT) establishes a continuous connection to applications and operating systems (with up to four virtual processors) in the event of a hardware failure in the VM.
FT creates a secondary virtual machine, which is an exact copy of the primary virtual machine in the event of a hardware failure and automatically failover to avoid downtime.
Since FT guarantees zero downtime, it is preferred when business availability is high.
High Availability (HA)
In a VMware High Availability (HA) scenario, when an ESXi host is shut down due to a hardware failure, the virtual machine of the failed host is automatically restarted on another host in the HA cluster.
It is important that this process runs automatically without manual intervention. HA has minimal downtime as VM restart is required. More information about HA can be found on this page
Q #18) Name some advantages of HA (High availability) and FT (Fault tolerance)
Advantages of HA:
- Monitor the entire VM infrastructure (host and VM) and detect errors and restart individual VMs or hosts on other hosts.
- It is an automatic and cost-effective restart of virtual machines and hosts when a server failure or operating system error is detected in the vSphere environment
Advantages of FT:
- It has no downtime, so it is usually used for very critical applications.
- Protects the operating system and applications regardless of hardware damage
- No loss of TCP connection during error.
Q #19) How do you set a VM to fault tolerance in a cluster with more than two hosts?
Answer: The IT admin can choose the primary VM but fault-tolerant (secondary) virtual machines are automatically chosen based on availability. Once the secondary virtual machine is online, it can be moved to another host using VMotion.
Q #20) What are the different components of VMware?
- ESX server host
- Virtual Centre Server
- Virtual Infrastructure (VI) client
- Web Access
- Virtual Machine File System (VMFS)
- VMware Virtual Symmetric Multi?Processing (SMP)
- VMotion and Storage VMotion
- VMware High Availability (HA)
- VMware Distributed Resource Scheduler (DRS)
- VMware Consolidated Backup (Consolidated Backup)
- VMware Infrastructure SDK
Q #21) What is VMKernel in VMware?
Answer: VMkernel is similar to the POSIX operating system used by VMware. It is the interface between a virtual machine and the physical hardware. It handles CPU scheduling, memory allocation, and other operating system services.
Q #22) What is vSwitch in VMware?
Answer: vSwitch is a virtual network switch used to connect virtual machines to ESXi hosts. Each ESXi host requires its own vSwitch.
Q #23) What is VMware Datastore and what are its types?
Answer: VMware Data Storage is a logical container that hides the virtual machine’s physical storage specifications and provides a single model for storing virtual machine files, log files, virtual disks, and ISO images.
Data storage can contain different types of storage, local storage, iSCSI, NAS (Network Access storage), SAN.
Types of Datastores
- VMFS: VMFS is a block-level file system used to store virtual machines and snapshots.
- NFS: NFS (Network File System) is built into ESXi hosts and uses the NFS-over-TCP/IP protocol to manage NFS NAS (Network Access Storage) volumes. ESXi hosts can mount NFS volumes and then use them for their storage needs.
- vSAN: A virtual storage network is a logical representation of a network consisting of physical storage areas. It is a software-defined storage product used in conjunction with the VMware ESXi hypervisor.
- vVol: The vVols datastore is a repository for vCenter Server and vSphere Client.
Read more about datastores here.
Q #24) What is VCloud Suite?
Answer: VMware vCloud Suite is a cloud infrastructure solution to provide advanced infrastructure management and solutions with the following integrated components:
vSphere: The building blocks of modern cloud infrastructure.
- vRealize Automation: Provides an advanced infrastructure automation platform for traditional and cloud workloads.
- vRealize Operations: Offers continuous performance optimization, efficient AI-based capacity and cost management, and forecast analysis.
- vRealize Log Insight: Provides centralized log management, deep operational visibility, and intelligent analysis.
- vRealize Suite Lifecycle Manager: Provides a complete application lifecycle and content management solution for vRealize Suite.
Q #25) What is the difference between LUN (logical unit numbers) and Datastore in VMware?
Answer: A LUN is a logical storage partition in a storage system. Data storage is in the form of a hard disk partition or LUN. A datastore is manageable storage for storing VM files like log files, configuration files, virtual data, etc.
You can create multiple data warehouses on a single LUN as a normal partition, and you can also link multiple LUNs to form one large datastore creation.
Q #26) What file system does VMware use and why?
Answer: VMware uses VMFS (Virtual Machine File System). It is used to save files, images, and screenshots in the VM. Multiple VMs can share a single VMFS, and the storage capacity can be increased by including multiple VMFS.
Q #27) What is the difference between SAN and vSAN?
Answer: SANs (Storage Networks) are mainly used to store data offering high performance and low latency. By storing data in a centralized SAN, security, data protection, and disaster recovery tools can be implemented reliably.
Traditional SAN (storage network) allocates storage space to different systems, while vSAN automatically converts local storage resources into a single storage pool. VMWare vSAN is a software-defined storage product used in conjunction with the VMware ESXi hypervisor. It provides and manages policy-based storage regardless of the underlying hardware.
VMWare vSAN reduces the cost and complexity of SAN solutions by providing the ability to deploy policies and rules for storage management. It prevents unauthorized access to data at rest through encryption and also supports deduplication.
Q #28) What are the preventative measures in VMware Infrastructure to avoid downtime?
Answer: To minimize disruption to VMware infrastructure, it is best to provide preventative support to avoid unexpected problems or errors with VMware.
Here are some important factors that require regular monitoring and maintenance:
- Outdated VMware Tools
- Outdated VM Network Devices
- VM Memory Limits
- Age and Size of VM Snapshots
We’ve tried to answer the most frequently asked questions about VMware technology. However, VMware is a very vast technology. So if you are looking for further questions or clarification, you can visit the VMware Knowledge base here.
Free Lab is provided by VMware to try the tools and usage of the platform at the below link. So before attending the VMware-related questions or interview, one can use this to get acquainted with all functions and features of VMware. Visit VMware lab