VMware Interview Questions and Answers

Introduction

VMware is one of the most well-known names in the technological industry of cloud computing and virtualization. There’s not an IT student, graduate, or job-seeker in the world who doesn’t know the name VMware. Vmware’s prominent features, like virtualizing hardware, are one of the most efficient ways to manage operating systems. Getting into the cloud computing industry or landing a job at VMware can be considered a great feather in anyone’s cap. Below are some of the top interview questions and answers for VMware, curated with thorough research.

VMware Interview Questions and Answers

What is VMkernel and explain its importance?

VMkernel is a virtualization interface that acts as a go-between a virtual machine and the ESXi host, which stores VMs. It is primarily responsible for allocating all available resources of the ESXi host to VMs, such as memory, CPU, storage, etc. It controls special services such as vMotion, fault tolerance, NFS, traffic management, and iSCSI. To access these services, the VMkernel port can be customized on the ESXi server using a standard or distributed vSwitch. Without the presence of the VM kernel, hosted VMs cannot communicate with the ESXi server.

Explain the major components of the VCenter server architecture.

vCenter Server provides a platform that is centrally managed for the management, operation, resource provisioning, and evaluation of the performance of virtual machines and hosts.

Whenever the vCenter server appliances are deployed, the vCenter server appliances, vCenter servers, vCenter server components, and authentication services are deployed on the same system.

The following are the components that are included in the vCenter Server appliance deployments:

The authenticating services contain vCenter single sign-on, license service, lookup service, and VMware certificate authority.

The vCenter Server group of services contains vCenter Server, vSphere Client, vSphere Auto Deploy, ESXi Dump Collector, and vSphere. The vCenter Server appliance also contains the VMware vSphere Lifecycle Manager Extension service and Manager.

What are the available disk types in VMware?

VMware’s Vsphere contains three main types of disks:

Thick Provisioned Lazy Zeroes: every virtual disk is created in this disk format by default. Physical space is allocated to a VM whenever a virtual disk is created. It cannot be converted to a thin disk.
Thick Provision Eager Zeroes: this disk type creates VM disks in a default thick format and allows maximum disk space when created.
This thin provision provides an allocation of disk space on-demand to a VM. When data size grows, the size of a disk will also grow along with it. Storage capacity allocation and on-demand capacity utilization can be up to 100% with thin provisioning.

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What are the different licensing options for vSphere version 6.0?

The following are three licensing options for vSphere version 6.0:

Standard Edition: Usually contains 1 vCenter Server Standard license and up to 2 vCPUs for Fault Tolerance, vMotion, Storage vMotion, HA, VVols, etc.
Enterprise Edition: It is quite the same as the standard edition, with additional APIs for array integration and multipathing, DRS, and DPM.
Enterprise Plus: It includes all standard and enterprise edition features with extra fault tolerance up to 4 vCPUs and 64GB of RAM. It also includes distributed vSwitch and some of the most expensive licensing options, including vSphere 6.0.

What are the advantages of using containers? (VMware troubleshooting interview)

Lightweight: Containers share a machine OS kernel, eliminating the need for a full operating system instance for one application and making container files small and easy on resources. Their smaller size, especially compared to VMs, means containers can spin up quickly and better support cloud-friendly applications that scale horizontally.
Portable and platform-independent: Containers carry all their dependents with them, which means that software can be written once and then run without needing to be re-configured across laptops, cloud computing, and on-premises computing environments across platforms.
Supports modern development and architecture: Due to a mixture of their deployment portability and consistency across platforms and their small size, containers are an apt fit for modern development and application patterns such as DevOps and are built using regular code deployments in small increments.
Improves utilization: Like VMs that came before them, containers encourage developers and operators to improve the CPU and memory utilization of physical machines. Where containers go even further is because they also have a microservice architecture and application components that can be deployed and scaled more easily. This is a good alternative to having to scale up an entire monolithic application because a single component is struggling with its load.

What are the types of virtualization?

The following are the available types of virtualization:

Server Virtualization: This type of virtualization has many virtual machines (VMs) running simultaneously on one physical server. Since users do not have to buy new servers or expand their server rooms, they save floor space and also save financially. Server virtualization is generally offered by a few well-known providers, such as vSphere, XenServer, Hyper-V, and RedHat.
Network virtualization: This is the process of combining all the physical network components into one virtual network. A virtual network is composed of NICs, switches, and VLANs; network storage devices; virtual network containers; and network media. This type of virtualization has the primary function of eliminating dependence on physical network devices. One of the examples of network virtualization is VMware NSX.
Application virtualization is the process of virtualizing and hosting applications on a server so that users on the end can have access to them on their devices, such as laptops, smartphones, and tablets. The app can be accessed via any Internet-connected device, so users don’t have to log in to a desktop to use it. Its examples include VMware ThinApp, Citric XenApp, etc.
Desktop Virtualization: AKA OS virtualization or VDI (Virtual Desktop Infrastructure), desktop virtualization is the process that enables users to run or deploy multiple virtual desktop OSes on a physical server. The user might access his or her virtual desktop from anywhere since it is stored on a server that is remotely present In this way, individual CPUs are not required. Its examples include VMware Horizon View, Citrix Xen Desktop, etc.
Storage Virtualization: By using storage virtualization, multiple network storage devices can be combined into a single storage device or array by pooling together their physical storage. This provides an easy way to manage storage and ensure consistent performance. Its example includes vSAN.

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What are the main components of VMware virtualization and explain how they contribute to the functions of VMware? (VMware troubleshooting interview)

The following are the different components of VMware’s virtualization:

VMware hypervisor: VMware virtualizes physical computers using its important product, the hypervisor. A hypervisor is a layer of software that interacts with the base resources of a physical computer, which is called the host and assigns those resources to other guest operating systems. The guest operating system requests and derives resources from the hypervisor. The hypervisor separates every guest OS so it can run without interruption from the others. If one guest operating system suffers a problem like an application crash, becomes unstable, or becomes infected with malware, it will not affect the performance or operation of other operating systems running on the host in any way
VMware ESX: VMware’s ESXi data center-focused hypervisor is a type 1, aka “bare metal” hypervisor, which replaces the primary operating system that would interact with a computer’s physical components. It is the successor to ESX, which was a bigger version of the hypervisor that used more of the host computer’s resources. VMware has discontinued ESX software since. Check out our VMware course syllabus to pique your interest.

What is RDM? (VMware interview questions)

RDM is the short form for Raw Device Mapping. In RDM, files are contained in VMFS, and they act as proxies for raw physical devices. This feature allows VMware’s virtual machines (VMs) to access logical unit numbers (LUNs) directly. This makes the need to use the virtual machine file system (VMFS) not compulsory because the LUN can be formatted using any file system, like NTFS (New Technology File System). It is in general very beneficial for cluster customization, including VM-to-VM, physical-to-VM, or SAN (Storage Area Network) snapshots. It also has some limitations, including the inability to map disk partitions and possibly not working with direct-attached block devices.

What is desktop virtualization, and what are its types?

Desktop virtualization is a technological process that simulates a workstation load to access a desktop from a connected device remotely or locally. This separates the desktop environment and associated application software from the physical client device used to access it; hence, both devices need not be in the same proximity.

Desktop virtualization works in a lot of ways, but the basic two types of desktop virtualization are based on whether the operating system instance is local or remote.

Local Desktop Virtualization: It establishes that the operating system runs on a client device where all processing and workloads occur on local hardware. This desktop virtualization works when users don’t need a constant network connection and can meet application computing requirements with local system resources. Although this requires processing to be done locally, users cannot use local desktop virtualization to share VMs or resources across a network with thin clients or mobile devices.

Remote Desktop Virtualization: Remote desktop virtualization is a very commonly used virtualization that operates in a client/server computing environment. It allows users to run operating systems from a server while all user interactions occur on a client device. The result is that IT departments have more centralized control over applications and desktops and can marginally increase the organization’s investment in IT hardware through remote access to shared computing resources.

What is Vmotion, and what are the prerequisites to configure it? (VMware troubleshooting interview questions and answers)

VMotion lets users to:

Automatically optimize and assign entire pools of resources for maximum utilization of hardware
Perform maintenance on hardware without any scheduled downtime.
Actively migrate virtual machines away from failing or underperforming servers.

Below are the pre-requisites for configuring vMotion

Each host must be accurately and legally licensed for vMotion
Each host must meet shared storage requirements for the software
vMotion migrates the VM from one host to another, which is only possible when both hosts share common storage or any storage accessible by both the source and target hosts. So one common storage system with access to it is necessary.
A shared storage system can either be on a fiber channel storage area network (SAN) or implemented using iSCSI SAN and NAS.
If users use vMotion to displace virtual machines with raw device mapping (RDM) files, they must make sure to maintain consistent LUN IDs for RDMs across all participating hosts.
Each host must have the networking requirements for the software
Customize a VMkernel port on each host.
Allocate at least one GigE adapter for vMotion.
Users should use at least one 10 GigE adapter if they migrate workloads that have many memory operations.
Use jumbo frames for the best-performing vMotion.
Users should ensure that the jumbo frames adapter is enabled on all network devices that are on the vMotion path, including physical NICs, physical switches, and virtual switches.

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What are some of the newly added features of the ESXi hypervisor enhancement?

The newly added features of the ESXi Hypervisor are as follows:

Hot-pluggable PCIe SSD Devices: This feature now supports SSD (Solid State Disks) devices. With a new enhancement, SSD devices can be added or removed while vSphere hosts are running.
Support for Reliable Memory Technology: vSphere ESXi hypervisor now has newly introduced hardware in the form of vendor-accessed Reliable Memory Technology. By using this, one region of memory capacity is reported from the hardware to the vSphere ESXi hypervisor. It is used to enhance the placement of VMKernel as well as the placement of other components, such as the initial thread or hosted. It helps with protection from memory errors.
Enhancements to CPU C-states: a new power process (C-state) that provides an additional level of power savings.

Expand the following abbreviations-

IOPS- stands for input/output operations per second
.vmdk- stands for the format of a VM disk file
NFS- stands for – Network File Systems.
iSCSI storage- full form, is the Internet Small Computer Systems Interface
VVoI- stands for Virtual Volume