VMWare Interview Questions and Answers

VMware, Inc. is an American publicly traded software company from California, USA. It provides cloud computing and virtualization software and services. It was one of the first commercially successful companies to virtualize the x86 architecture.

VMware’s desktop software runs on Microsoft Windows, Linux, and macOS, while its enterprise software hypervisor for servers, VMware ESXi, is a bare-metal hypervisor that runs directly on server hardware without requiring an additional underlying operating system.

Below we have listed the top 100 Vmware interview questions & answers for fresher and experienced candidates to clear the job interview. 

1.What is VMKernel and why is it important?

Ans:

VMkernel is a virtualization interface between a Virtual Machine and the ESXi host which stores VMs. It is responsible to allocate all available resources of ESXi host to VMs such as memory, CPU, storage etc. It also controlled special services such as vMotion, Fault tolerance, NFS, traffic management and iSCSI. To access these services, VMkernel port can be configured on ESXi server using a standard or distributed vSwitch. Without VMkernel, hosted VMs cannot communicate with ESXi servers.

2.What is the hypervisor and its types?

Ans:

A hypervisor is a virtualization layer that enables multiple operating systems to share a single hardware host.  Each operating system or VM is allocated physical resources such as memory, CPU, storage etc by the host. There are two types of hypervisors

• Hosted hypervisor (works as application i-e VMware Workstation)
• Bare-metal (is virtualization software i-e VMvisor, Hyper-V which is installed directly onto the hardware and controls all physical resources).

3.What is Virtualization?

Ans:

The process of creating virtual versions of physical components i-e Servers, Storage Devices, Network Devices on a physical host is called virtualization. Virtualization lets you run multiple virtual machines on a single physical machine which is called ESXi host.

4.What are the different types of virtualization?

Ans:

There are 5 basic types of virtualization

• Server virtualization: consolidates the physical server and multiple OS can be run on a single server.
• Network Virtualization: Provides complete reproduction of physical network into a software-defined network.
• Storage Virtualization: Provides an abstraction layer for physical storage resources to manage and optimize in virtual deployment.
• Application Virtualization: increased mobility of applications and allows migration of VMs from a host on another with minimal downtime.
• Desktop Virtualization: virtualize desktop to reduce cost and increase service

5.What is VMware FT?

Ans:

FT stands for Fault Tolerance, a very prominent component of VMware vSphere. It provides continuous availability for VMs when an ESXi host fails. It supports up to 4 vCPUs and 64 GB memory. FT is very bandwidth intensive and 10GB NIC is recommended to configure it. It creates a complete copy of an entire VM such as storage, compute, and memory.

6.How many vCPUs can be used for a VM in FT?

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In vSphere 6.0, there can be up to 4 vCPUs and 64 GB RAM can be used.

7.What is the name of the technology used by VMware FT?

Ans:

vLockstep technology is used by VMware FT

8.What is Fault Tolerant Logging?

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The communication between two ESXi hosts is called FT logging when FT is configured between them. The prerequisite of configuring FT is to configure VMKernel port.

9.Will the FT work if vCenter Server goes down?

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vCenter server is only required to enable Fault Tolerance on a VM. Once it is configured, vCenter is not required to be online for FT to work. FT failover between primary and secondary will occur even if the vCenter is down.

10.What is the main difference between VMware HA and FT?

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The main difference between VMware HA and FT is: HA is enabled per cluster and VMware FT is enabled per VM. In HA, VMs will be re-started and powered-on on another host in case of a host failure, while in FT there is no downtime because the second copy will be activated in case of host failure.

11.What is virtual networking?

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A network of VMs running on a physical server that is connected logically with each other is called virtual networking.

12.What is vSS?

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vSS stands for Virtual Standard Switch is responsible for communication of VMs hosted on a single physical host. It works like a physical switch automatically detects a VM which wants to communicate with another VM on the same physical server.

13.What is vDS?

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vDS stands for Virtual Distributed Switch acts as a single switch in a whole virtual environment and is responsible to provide central provisioning, administration, and monitoring of the virtual network.

14.How many maximum standard ports per host available?

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4096 ports per host are available either in a standard switch or distributed switch.

15.What are the main benefits of distributed switch (vDS)?

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vDS can provide:

• Central administration for a data center
• Central provision, and
• Monitoring

16.What is the VMKernal adapter and why is it used?

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VMKernel adapter provides network connectivity to the ESXi host to handle network traffic for vMotion, IP Storage, NAS, Fault Tolerance, and vSAN. For each type of traffic such as vMotion, vSAN etc. separate VMKernal adapters should be created and configured.

17.What is the main use of port groups in data center virtualization?

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You can segregate the network traffic by using port groups such as vMotion, FT, management traffic etc.

18.What three port groups are configured in ESXi networking?

Ans:

• Virtual Machine Port Group – Used for Virtual Machine Network
• Service Console Port Group – Used for Service Console Communications
• VMKernel Port Group – Used for VMotion, iSCSI, NFS Communications

19.What is VLAN and why is it used in virtual networking?

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A logical configuration on the switch port to segment the IP Traffic where each segment cannot communicate with other segments without proper rules mentioned is called VLAN and every VLAN has a proper number called VLAN ID.

20.What is VLAN Tagging?

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The practice of inserting VLAN ID into a packet header to identify which VLAN packet belongs to is called VLAN tagging.

21.What are the three network security policies/modes on vSwitch?

Ans:

• Promiscuous mode
• MAC address change
• Forged transmits

22.What is the promiscuous mode on vSwitch?

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Promiscuous mode is a security policy that can be defined at the virtual switch or portgroup level in vSphere ESX/ESXi. A virtual machine, Service Console, or VMkernel network interface in a portgroup that allows the use of promiscuous mode can see all network traffic traversing the virtual switch.

By default, a guest operating system’s virtual network adapter only receives frames that are meant for it. Placing the guest’s network adapter in promiscuous mode causes it to receive all frames passed on the virtual switch that are allowed under the VLAN policy for the associated portgroup. This can be useful for intrusion detection monitoring or if a sniffer needs to analyze all traffic on the network segment.

23.What MAC address changes network policy?

Ans:

• The security policy of a virtual switch includes a MAC address change option. This option affects traffic that a virtual machine receives.
• When the Mac address changes option is set to Accept, ESXi accepts requests to change the effective MAC address to a different address than the initial MAC address.
• When the Mac address change option is set to Reject, ESXi does not honor requests to change the effective MAC address to a different address than the initial MAC address. This setting protects the host against MAC impersonation.

24.What is Forged transmits network policy?

Ans:

The Forged transmits option affects traffic that is transmitted from a virtual machine.

When the Forged transmits option is set to Accept, ESXi does not compare source and effective MAC addresses.

25.What are the main components of vCenter Server architecture?

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There are three main components of vCenter Server architecture.

• vSphere Client and Web Client: a user interface.
• vCenter Server database: SQL server or embedded PostgreSQL to store inventory, security roles, resource pools etc.
• SSO: a security domain in a virtual environment

26.What is PSC and its components?

Ans:

PSC stands for Platform Services Controller first introduced in version 6 of VMware vSphere which handles infrastructure security functions. It has three main components.

• Single Sign-On (SSO)
• VMware Certificate Authority (CA)
• Licensing service

27.What are the two main deploying methods of PSC

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You can install PSC in two ways:

• Embedded
• centralized

28.What are different types of vCenter Server deployment?

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It has two deployment types

• Embedded Deployment
• External deployment

29.What is vRealize Operation (vROP)

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vROP provides the operation dashboards for performance analytics, capacity optimization and monitoring the virtual environment.

30.What is the basic security step to secure vCenter Server and users?

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Authenticate vCenter Server with Active Directory. By using this we can assign specific roles to users and can also manage the virtual environment in an efficient way.

31.What is datastore?

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Datastore is a storage location where virtual machine files are stored and accessed. Datastore is based on a file system which is called VMFS, NFS.

32.What is the .vmx file?

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It is the configuration file of a VM

33.What information .nvram file stores?

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It stores BIOS related information of a VM.

34.What.vmdk file does and uses?

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Vmdk is a VM disk file and stores data of a VM. It can be up to 62 TB in size in vSphere 6.0 version.

35.How many disk types are in VMware?

Ans:

There are three disk types in vSphere.

• Thick Provisioned Lazy Zeroed: every virtual disk is created by default in this disk format. Physical space is allocated to a VM when a virtual disk is created. It can’t be converted to a thin disk.
• Thick Provision Eager Zeroed: this disk type is used in VMware Fault Tolerance. All required disk space is allocated to a VM at time of creation. It takes more time to create a virtual disk compared to other disk formats.
• Thin provision: It provides an on-demand allocation of disk space to a VM. When data size grows, the size of a disk will grow. Storage capacity utilization can be up to 100% with thin provisioning.

36.What is Storage vMotion?

Ans:

It is similar to traditional vMotion, in Storage vMotion, a virtual disk of a VM is moved from one datastore to another. During Storage vMotion, virtual disk types think provisioning disk can be transformed to thin provisioned disk.

37.In which version of vSphere PSC was introduced?

Ans:

Platform Services Controller (PSC) is introduced in vSphere 6.0. vSphere 6.0 is also known as Virtual hardware version 11.

38.How many maximum hosts can manage a vCenter Server in vSphere 6.0?

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In vSphere 6.0, a single vCenter Server can manage up to 1000 hosts either in Windows or in vCenter Appliance (vCSA).

39.How many hosts can be managed by a cluster in vSphere 6.0?

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A single cluster can manage maximum 64 hosts

40.How can maximum VMs be managed by a single cluster?

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A single cluster can manage the maximum of 8000 VMs.

41.What is VVol?

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Virtual Volume a new VM disk management concept introduced in vSphere 6.0 that enables array-based operations at the virtual disk level. VVol is automatically created when a virtual disk is created in a virtual environment for a VM.

42.How many licensing options for vSphere 6.0?

Ans:

There are three licensing options for vSphere 6.0:

• Standard Edition: Contains 1 vCenter Server Standard license, up to 2 vCPUs for Fault Tolerance, vMotion, Storage vMotion, HA, VVols etc.
• Enterprise Edition: Same as Standard Edition additionally APIs for Array Integration and Multipathing, DRS, and DPM.
• Enterprise Plus: Includes all features of Standard and Enterprise Editions with additionally Fault Tolerance upto 4 vCPUs and 64GB of RAM. It also includes Distributed vSwitch and the most expensive licensing option of vSphere 6.0.

43.How much Maximum RAM can support vSphere 6.0?

Ans:

It supports upto 12TB of RAM.

44.What is the Content Library?

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Content Library is the central location point between two different geographical locations with vCenter Servers where you can store VM templates, ISO images, scripts etc. and share them between geographical locations.

45.Define virtual desktop infrastructure?

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Virtual Desktop Infrastructure hosts the desktop in the commission system on the central server in a data centre. It is also known as server-based computing as it is the difference between the client-server computing replica. The end-user gets associated with their desktop by using the thin client.

46.Explain Virtual Smp?

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When and why you must give a VM numerous vCPUs part of their answer would be that best performance is to create with a single vCPUs because you can sprint into presentation issues due to CPU preparation.

47.Tell me about the use of a port group?

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The port cluster segregates the kind of communication.

48.What do you mean by a template?

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We can exchange a VM into Template, and it cannot be motorized on once it’s changed to the pattern. This is used for rapid provisioning of VMs.

49.How to set the time delay for Bios Screen for a virtual machine?

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Right Click on VM, choose edit settings, decide options tab and go for boot option, set the setback as per our wish.

50.Explain vCloud Suite?

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VCloud Suite combines with many VMware components to give a total set of cloud communications capabilities in a solitary package, including virtualization, software-defined datacenter services, disaster revival application organization etc.

51.What do you mean by cold and hot migration?

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When you drift powered off or balanced, it is known as cold migration. When you migrate your administration power on virtual machines, it is known as hot immigration.

52.Tell me the importance of snapshot in VMware?

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A VMware snapshot is a print of a virtual machine disk file which is used to re-establish a VM to a precise point in time when the scheme fails, or structure error occurs.

53.Define cluster in VMware?

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Clusterin VMware is a rational grouping of multi ESXi hosts. It permits you to add or remove the host from the cluster. It also provides a characteristic like HA, DRS, on the group.

54.Define NFS?

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NFS is known as the Network file system. It is a file distribution protocol which ESXi hosts used to converse with the NAS device. It is a dedicated storage device which connects to a system and can offer file aces service to ESXi hosts.

55.What do you mean by VMware consolidated backup?

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It is an endorsement framework that supports 3rd party utilities to take backups of ESX servers and Virtual Machines. It’s not a support service.

56.What you can do to customize the windows virtual machine clone?

Ans:

Copy the Sysprep files to Virtual middle directory on the server, so that the wizard will take advantage of it.

57.Define the resource pool and the use of it?

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A resource pool is a sensible concept for elastic management of resources. Resource pools can be grouped into hierarchies and utilized to hierarchically divide.

58.What do you understand by Virtual Machine?

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• A virtual computer system is known as “virtual machine” (VM): a tightly isolated software container with an operating system and application inside.
• Each self-contained VM is completely independent. Putting multiple VMs on a single computer enables several operating systems and applications to run on just one physical server, or “host”.

59.What are the key properties of a Virtual Machine?

Ans:

• Partitioning
  Run multiple operating systems on one physical machine
  Divide system resources between virtual machines
• Isolation
  Provide fault and security isolation at the hardware level
  Preserve performance with advanced resource controls
• Encapsulation
  Save the entire state of a virtual machine to files
  Move and copy virtual machines as easily as moving and copying files
• Hardware Independence
  Provision or migrate any virtual machine to any physical server

60.What are the main advantages of VMWare Vsphere?

Ans:

• Ensure business continuity and always available IT
• Reduce IT hardware and operating costs
• Improve application quality
• Enhanced security and data protection

61.What is a Data Store?

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Data store represents a storage location for virtual machine files. It can be a Virtual Machine File System (VMFS) volume, a directory on Network Attached Storage, or a local file system path.

62.What is VMware DRS?

Ans:

VMware DRS stands for Distributed Resource Scheduler; it dynamically balances resources across various hosts under cluster or resource pool. It enables users to determine the rules and policies which decide how virtual machines deploy resources, and these resources should be prioritized to multiple virtual machines.

63.When using ESXi hypervisor architecture, how to monitor hardware on vSphere host?

Ans:

vSphere supports CIM API and SNMP v2, without installing agents to enable hardware monitoring. Hardware monitoring tools can monitor through vCenter console and major hardware provided by OEM vendors.

64.What is VMware DPM?

Ans:

VMware Distributed Power Management (DPM) is a pioneering new feature of VMware DRS that continuously monitors resource requirements in a VMware DRS cluster. When resource requirements of the cluster decrease during periods of low usage, VMware DPM consolidates workloads to reduce power consumption by the cluster. When resource requirements of workloads increase during periods of higher usage, VMware DPM brings powered-down hosts back online to ensure service levels are met.

65.When you visit certain Websites, the request is “connection was reset” the report, then what is the principle of connection is reset?

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The nature of the connection is reset, because it has received a TCP Reset packet damage connected

66.VMware ESX is still providing support for the architecture?

Ans:

VMware will follow VMware vSphere support policy to continue to provide technical support for ESX architecture.

67.How can I evaluate VMware vSphere?

Ans:

The easiest way to evaluate VMware vSphere is to download and install the free vSphere Hypervisor version. In addition, you can also use vSphere assessment .

68.When using the ESXi architecture, Update Manager whether to repair my vSphere host?

Ans:

VMware vCenter Update Manager will be updated to run ESXi host. In addition, the VMware Update Manager environment does not install the update utility.

69.What is the ESXi Shell?

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ESXi Shell is a command-line interface to run diagnostics and repair of vSphere ESXi hosts. ESXi Shell by DCUI or through vCenter Server to enable and disable, and can also be accessed remotely via SSH. For more information, see the ESXi Management page.

70.What are the advantages and disadvantages of VMWare workstation?

Ans:

Advantage:

• VMware Workstation virtual machine capability, performance and physical isolation is very good!
• VMware Workstation features a very comprehensive, computer professionals tend to use!
• VMware Workstation is a simple interface for users of various fields of computer!

Disadvantages:

• VMware Workstation bulky, longer installation time-consuming!
• VMware Workstation occupies a larger physical machine resource when using!

71.Can we do vMotion between two datacenters ? If possible how will it be?

Ans:

Yes we can do vMotion between two datacenters, but the mandatory requirement is the VM should be powered off.

72.What is a VC agent? and what service it is corresponding to? What are the minimum req’s for VC agent installation ?

Ans:

• VC agent is an agent installed on ESX server which enables communication between VC and ESX server.
• The daemon associated with it is called vmware-hostd , and the service which corresponds to it is called as mgmt-vmware, in the event of VC agent failure just restart the service by typing the following command at the service console ” service mgmt-vmware restart ”
• VC agents installed on the ESX server when we add it to the VC, so at the time of installation if you are getting an error like ” VC Agent service failed to install “, check the /Opt size whether it is sufficient or not.

73.How can you edit VI Client Settings and VC Server Settings ?

Ans:

• Click Edit Menu on VC and Select Client Settings to change VI settings
• Click Administration Menu on VC and Select VC Management Server Configuration to Change VC Settings

74.What are the files that make a Virtual Machine ?

Ans:

75.What are the devices that can be added while the virtual Machine running?

Ans:

In VI 3.5 we can add Hard Disk and NIC’s while the machine is running.

In vSphere 4.0 we can add Memory and Processor along with HDD and NIC’s while the machine running

76.What is a template ?

Ans:

We can convert a VM into Template, and it cannot be powered on once its changed to template. This is used for quick provisioning of VM’s.

77.What to do to customize the windows virtual machine clone?

Ans:

Copy the sysprep files to Virtual center directory on the server, so that the wizard will take advantage of it.

78.What to do to customize the linux/unix virtual machine clone,?

Ans:

VC itself includes the customization tools, as these operating systems are available as open source.

79.Does cloning from a template happen between two datacenters ?

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Yes. it can, if the template is in one datacenter, we can deploy the vm from that template in another datacenter without any problem.

80.What are the common issues with snapshots? What stops from taking a snapshot and how to fix it ?

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If you configure the VM with Mapped LUN, then the snapshot failed. If it is mapped as virtual then we can take a snapshot of it.

If you configure the VM with Mapped LUN as physical, you need to remove it to take a snapshot.

81.What are the settings that are taken into consideration when we initiate a snapshot ?

Ans:

• Virtual Machine Configuration (What hardware is attached to it)
• State of the Virtual Machine Hard Disk file ( To revert back if needed)
• State of the Virtual Machine Memory (if it is powered on)

82.What are the requirements for Converting a Physical machine to VM ?

Ans:

• An agent needs to be installed on the Physical machine
• VI client needs to be installed with Converter Plug-in
• A server to import/export virtual machines

83.What is VMWare consolidated backup ?

Ans:

It is a backup framework, that supports 3rd party utilities to take backups of ESX servers and Virtual Machines. It’s not a backup service.

84.To open the guided consolidation tool, what are the user requirements ?

Ans:

The user must be member of administrator, The user should have “Logon as service” privileges – To give a user these privileges, open local sec policy, select Logon as service policy and add the user the user should have read access to AD to send queries

85.Explain the physical topology of Virtual Infrastructure 3 Data Centre?

Ans:

A typical VMware Infrastructure data center consists of basic physical building blocks such as x86 computing servers, storage networks and arrays, IP networks, a management server and desktop clients.

86.How do you configure Clusters, Hosts, and Resource Pools in VI3?

Ans:

A cluster is a group of servers working together closely as a single server, to provide high availability, load balancing and high performance. A host is a single x86 computing server with individual computing and memory resources. Resource pools are allocation of the available resources into pieces for the proper distribution.

87.What makes iSCSI and FC different ?

Ans:

Addressing Scheme, iSCSI relies on IP and FC not, and the type of transfer of data also. In FC the data transferred as blocks, in iSCSI the data transferred as files. The cabling also, FC uses Fibre cable and iSCSI uses RJ45.

88.What is the format for iSCSI addressing ?

Ans:

IP Address

89.VM’s Task Manager shows performance normal, But vCenter reports high resource utilization, what is the reason ?

Ans:

VM’s performance normal, vCenter reports high resource utilization

90.How can we list pNICs & status using the command line ?

Ans:

91.What is VMware Tools?

Ans:

VMware Tools is defined as a suite of utilities that we use to install in the operating system of a virtual machine. VMware Tools helps in enhancing the performance of a virtual machine. You can install VMware Tools on Windows as well as Linux Operating Systems. VMware Tools has various advantages such as the faster graphics performance, synchronization of Clock in VM, improved mouse performance, Copy and paste text & files, and many more.

92.What is the Hardware Version?

Ans:

The hardware version of a virtual machine helps in reflecting the virtual machine  that supports the virtual hardware features. These features correspond to the physical hardware which is available on the ESXi host on which we are capable of creating the virtual machine. Virtual hardware features include BIOS and EFI, maximum memory configuration, available virtual PCI slots, maximum number of CPUs, and other characteristics typical to hardware. You can easily upgrade the Hardware version of Virtual Machine but it requires the virtual machine to be powered off.

93.What are the Memory Management Techniques in VMware?

Ans:

ESXi uses 4 types of Memory management Techniques to reclaim memory when physical memory is not available. Below are 4 types:

• Transparent Page Sharing (TPS):

Transparent Page Sharing is used when multiple virtual machines are making use of the same operating system. So, at that time ESXi will check for the identical memory pages and it will be keeping a single copy of the identical pages by removing the redundant pages. This technique will help the ESXi for reclaiming the memory easily. It is enabled by default.

• Memory Ballooning:

Ballooning is a dynamic memory reclamation technique used when ESXi is running out of memory and it uses balloon drivers to reclaim memory from VMs. Balloon driver is itself included in the VMware Tools which is installed in the VM.

• Memory Compression:

When the Ballooning isn’t able to reclaim the memory then ESXi makes use of the Memory Compression. It helps in compressing and storing the memory in a cache in the host’s main memory. Memory compression takes place when we find that the page’s compression ratio is greater than 50%. It gets enabled by default.

• Hypervisor based memory swapping:

When the TPS, Ballooning and Memory compression are not in working conditions then the ESXi makes use of the Memory Swapping in which ESXi is used to swap guest VMs memory to the swap file which is used to make the physical memory available.

94.What is Standard Switch?

Ans:

A vSphere Standard Switch is very similar to a physical Ethernet switch. You use standard switches for providing network connectivity to the virtual machines and hosts. A standard switch is capable of bridging the traffic internally between links to external networks and the virtual machines in the same VLAN. In order to provide the network connectivity to the virtual machines and the hosts, you can connect to the physical NICs of the hosts for up linking the ports on the standard switch.

95.What is a Distributed Switch?

Ans:

A vSphere distributed switch function is defined as a single switch across all the associated hosts. This is enabling you for setting the network configurations that are spanning across all the member hosts which allows the virtual machines for maintaining the consistent network configuration as they migrate across multiple hosts. In Standard Switch you need to create Port Groups on each host but in case of Distributed Switch you only have to create port groups once and it will be applied to all hosts.

96.What is Traffic Shaping?

Ans:

ESXi allows you to shape the incoming and outgoing traffic on Port Groups. A traffic shaping policy is the policy which is defined by various characteristics such as: average bandwidth, peak bandwidth, and burst size. Standard switch only supports the outbound traffic shaping.

97.What is Port Group?

Ans:

Port Groups aggregates multiple ports of virtual machines. Each port group in this VMware gets identified by a network label which is unique for the current host. Network labels are used in making the virtual machine configuration portable across the various hosts. You can either create a VMkernel port group or VM port group based on requirements. You can set VLAN IDs on Port Groups.

98.What is VCHA?

Ans:

VCHA is the new feature announced in vSphere 6.5. VCHA is referred to as vCenter High Availability. VCHA provides high availability for the vCenter Server by the creation of the secondary copy of the vCenter Server. So in case your primary vCenter fails, a secondary vCenter will take over it and you have your vCenter Server running.

These are some of the popular questions that are asked in Vmware interviews. Always be prepared to answer all types of questions — technical skills, interpersonal, leadership or methodology. If you are someone who has recently started your career in this field, you can always get certified to understand the industry-related terminology, skills and methodologies.