Basic Interview Questions VMware

1.       What is VMware?

VMware is a virtualization and cloud computing software provider,   With VMware server virtualization, a hypervisor is installed on the physical server to allow for multiple virtual machines (VMs) to run on the same physical server.

2.       What is Virtualization?

The process of creating virtual versions of physical components i-e Servers, Storage Devices, Network Devices on a physical host is called virtualization.

Save more than 50% of total cost spend on IT.

It reduces the amount of physical servers.

It simplifies IT management and speed up the deployment of new applications

3.       What is Virtual Machine?

Virtual machines are based on computer architectures and provide functionality of a physical computer.

4.       How many licensing options?

Standard Edition / Enterprise Edition / Enterprise Plus.

5.       What is the purpose of VMware Tools?

VMware Tools is used to enhance the performance of a VM in the form of graphics, mouse/keyboard movement, network card, and other peripheral devices.

6.       What is VMKernel and why it is important?

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’s also controlled special services such as vMotion, Fault tolerance, NFS, traffic management and iSCSI.

Without VMkernel, hosted VMs cannot communicate with ESXi server.

7.       What is the hypervisor and its types?

Hypervisor is a program that enables multiple operating systems to share a single hardware host. 

Hosted hypervisor (works as application i-e VMware Workstation)

Bare-metal (is virtualization software i-e VMvisor, Hyper-V)

8.       What is ESXi Host?

Virtualization lets you run multiple virtual machines on a single physical machine which is called ESXi host.

9.       What is ESXi Shell?

ESXi Shell is a command-line interface is used to run repair and diagnostics of ESXi hosts. It can be accessed via DCUI, vCenter Server enable/disable, and via SSH.

10.   What ESXi stand for?

Elastic Sky X

11.   What are the different types of Partitions in ESX server?

/ -root
Swap
/var
/Var/core
/opt
/home
/tmp

12.   How to run ESXTOP on ESXi host?

To run ESXTOP on an ESXi host, we’ll need two pre-requisites:

1.       Install vSphere Client on a host where you want to configure

2.       Enable SSH from DCUI by using “Troubleshooting Options” link

13.   What are the different 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

14.   What is VMware FT?

FT stands for Fault Tolerance 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.

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

vLockstep Technology.

16.   What is Vlockstep Technology?

It’s captures inputs,movements and events that occur on a primary VM and sends them to a secondary VM.

17.   What is Fault Tolerant Logging?

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

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

vCenter server is only required to enable Fault Tolerance on a VM. Once it is configured, vCenter is not required to be in online for FT to work.

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

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.

20.   What monitoring method is used in vSphere HA?

• Network Heartbeat
• Datastore Heartbeat

21.   How is the master host elected in vSphere HA?

When HA is enabled in a cluster, all hosts take part in a selection process to be selected as a master host. A host which has the highest number of datastores mounted will be selected as a master host. All other hosts will remain slave hosts.

22.   What are the roles of a master host in vSphere HA?

Monitoring the state of slave hosts. If a slave host fails or becomes unreachable, the master host identifies which virtual machines need to be restarted.

Monitoring the power state of all protected virtual machines. If one virtual machine fails, the master host ensures that it is restarted. Using a local placement engine, the master host also determines where the restart should be done.

23.   What is virtual networking?

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

24.   What are the two types to switches in vmware?

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 want to communicate with other VM on a same physical server.

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.

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

vDS can provide:

·         Central administration for a data center

·         Central provision, and

·         Monitoring

26.   How many maximum standard ports per host available?

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

27.   What is VMKernal adapter and why it used?

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 adapter should be created and configured.

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

Virtual Machine Port Group – Used for Virtual Machine Network

Service Console Port Group – Used for Service Console Communications. vCenter/vSphere Client uses the service console IP’s to communicate with the ESX server.

VMKernel Port Group – Used for VMotion, iSCSI, NFS Communications

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

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

30.   What is the default number of ports configured with the Virtual Switch?

When the time of Virtual switch created, Vswitch is created with 56 ports by default.

31.   What is VLAN and why use in virtual networking?

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.

32.   What is VLAN Tagging?

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

1..Virtual Switch Tagging (VST)
2.External Switch Tagging (EST)
3.Virtual Guest Tagging (VGT)

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

The default mode is Reject.

Promiscuous mode - If Accept is selected, VM will receive all traffic port group via vSwitch.

MAC address change - If the Accept is selected, a host will accept requests to change the effective MAC address.

Forged transmits - If Accept is selected, a host will not compare the source and effective MAC address transmitted from a VM.

34.   What is vCenter server?

vCenter Server is the centralized management utility for VMware, and is used to manage virtual machines, multiple ESXi hosts, and all dependant components from a single centralized location. VMware vMotion and svMotion require the use of vCenter and ESXi hosts.

35.   What is the distinction between vCenter and vSphere?

vCenter server is analogous to vSphere consumer however it is a software package with additional power.vCenter server is put in on Windows Server or UNIX system Server or desktop/laptop.VMware vCenter server could be a centralized management application that allows you to manage virtual machines and ESXi hosts centrally.

36.   What are the 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

37.   What are different types of vCenter Server deployment?

• Embedded Deployment
• External deployment

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

Authenticate vCenter Server with Active Directory and assign specific roles to the users to manage the virtual environment.

39.   What is the command used to restart SSH, NTP & Vmware Web access?

Service sshd restart

Service ntpd restrat

Service vmware–webaccess restart

40.   How many maximum hosts can manage a vCenter Server?

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

41.   How many hosts can be managed by a cluster?

In  vSphere 6.0, a single cluster can manage maximum 64 hosts

42.   How many VMs can be managed by a single cluster?

A single cluster can manage the maximum of 8000 VMs.

43.   What is PSC and its components?

Introduced in vSphere 6.0, Platform Services Controller handles infrastructure security functions.

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

44.   What are the main deploying methods of PSC ?

You can install PSC in two ways:

• Embedded
• Centralized

45.  What is vRealize Operation (vROP)?

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

46.   What is datastore?

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.

47.   What is VMFS?

VMFS is a file system that responsible for storing virtual machine files. In vSphere 6.0, can store upto 64 TB.

48.   What is NFS?

Network File System (NFS) is a file sharing protocol that ESXi hosts use to communicate with a NAS device.

49.   What is Raw Device Mapping (RDM)?

Raw Device Mapping (RDM) is a file stored in a VMFS volume that acts as a proxy for a raw physical device. RDM enables you to store virtual machine data directly on a LUN.

50.   What are the files in VMware?

.vmx – Configuration file of a VM

.nvram file - BIOS related information of a VM.

.vmdk - 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.

51.   What will happen if the .nvram file is deleted accidently from a VM?

.nvram file is employed to store the BIOS state of a VM. If it deleted for a few reason, then, .nvram file are created once more once the virtual machine is battery-powered on.

52.   How many disk types are in VMware?

·  Thick Provisioned Lazy Zeroes: This is the default virtual disk format in VMware. Physical space is allocated to a VM when a virtual disk is created. It can’t be converted to thin disk.

·  Thick Provision Eager Zeroes: It is used for Fault Tolerance. All required disk space is allocated to a VM at time of creation. It takes more time to create a virtual disk compare 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.

53.  What is VVol?

Introduced in vSphere 6.0, Virtual Volume enables array-based operations at the virtual disk level and it is automatically created when a virtual disk is created in a virtual environment for a VM.

54.   What are supported Hardware versions in Vmware?

Vsphere 5.5 – version 10

Vsphere 6.0 – version 11

Vsphere 6.5 – version 13

55.   What is the Content Library and its benefits?

Content Library is the central location point between two different locations for vCenter server to store and share VM templates, ISO images, scripts etc.,

56.   How many types of Content Libraries?

·  Local: library of local control.

·  Published: local library which contents (VM templates, ISO images etc) for subscription.

·  Subscribed: A library which syncs with the published library

57.   What are the requirements and limitations of Content Libraries?

Single storage which can size upto 64TB

Maximum of 256 items per library

Sync occurs once every 24 hours

58.   How many types of storages can we use in our virtual environment?

• Direct Attached Storage
• Fiber Channel (FC)
• iSCSI
• Network Attached Storage (NAS)

59.  What is iSCSI storage?

An iSCSI SAN consists of an iSCSI storage system, which contains one or more storage processors. TCP/IP protocol is used to communicate between host and storage array. an iSCSI initiator is configured with the ESXi host. an iSCSI initiator can be a hardware-based either dependent or independent and software-based known as iSCSI software initiator.

60.  What is the format of iSCSI addressing?

It uses TCP/IP to configure.

61.  What are the iSCSI naming conventions?

 iSCSI Qualified Name (IQN)

Extended Unique Identifier (EUI)

62.   What is vSAN?

Virtual SAN is a software-defined storage which is locally attached storage of ESXi hosts which are part of a cluster and creates a distributed shared solution.

63.   What are the different configuration options for VSAN?

Hybrid: Uses both flash-based and magnetic disks for storage. Flash are used for cashing, while magnetic disks are used for capacity or storage.

All-Flash: Uses flash for both caching and for storage

64.  Are there VSAN ready nodes are available in the market?

Yes, vSAN-ready such as VxRail 4.0 and 4.5 are available in the market. VxRail is the combination of min 3 servers which are part of a cluster and can scale up to 64 servers.

65.   What is the minimum servers/hosts are required to configure vSAN?

Minimum 3 ESXi hosts/servers is required to configure the vSAN cluster. If one of the servers fails, a vSAN cluster will fail.

66.   How many maximum ESXi hosts allowed for vSAN?

64 hosts are max allowed to configure a vSAN cluster.

67.   How many disk groups and max magnetic disks are allowed in single disk group?

Maximum 5 disk groups are allowed on an ESXi host which is a part of a vSAN cluster and a maximum of 7 magnetic and 1 SSD per disk group is allowed.

68.   What is cold migration?

To move a powered-off VM from one host to another is called cold migration.

69.   What is vMotion and its purpose?

VMware VMotion enables the live migration of running virtual machines from one physical server to another with zero downtime.

70.   What are the pre-requisites for configuring vMotion?

Each host must be correctly licensed for vMotion

Each host must meet shared storage requirements

Each host must meet the networking requirements

Configure a VMkernel port on each host

71.   What is Storage vMotion?

To move a powered-on VM from one datastore to another is called Storage vMotion.

72.   What is vApp?

vApp is a container or group where more than one VM can be package and manage multi-tiered applications for specific requirements for example, Web server, database server, and application server can be configured as a vApp and can be defined their power-on and power-off sequence.

73.   What settings can be configured for vApp?

We can configure several settings for vApp such as CPU and memory allocation, and IP allocation policy etc.

74.   What is VMware DRS?

Distributed Resource Scheduler can automatically balances available resources among various hosts by using cluster or resource pools.

75.   What is share, limit, and reservation?

Share: A value that specifies the relative priority or importance of a VM access to given resource.

Limit: Consumption of a CPU cycle or host physical memory that cannot cross the defined value (limit).

Reservation: This value defines in the form of CPU or memory and must be available for a VM to start.

76.   What is VMware DPM?

Distributed Power Management is a feature of VMware DRS is used to monitor required resources in a cluster. When the resources are decreases due to low usage, VMware DPM consolidates workloads and shut down the hosts which are not being used, and when resources are increased it automatically power on the un-used hosts.

77.   What are the alarms why we use them?

An alarm is a notification which appears when an event occurs. Many default alarms exist for many inventory objects. Alarms can be created and modified using vSphere Web Client;

78.   What are the hot-pluggable devices which can be added while VM is running?

We can add HDDs and NIC while VM is running.

79.   What is a Template?

When a VM is converted into a format which can be used to create a VM with pre-defined settings is called a template. An installed VM can be converted into a template but it cannot be powered-on.

80.   Difference between Clone Vs Template in VMware?

Clone:  A Copy of virtual machine

Template - A master copy or a baseline image of an virtual machine that shall be used to create many clones.

81.   What is Snapshot?

To create a copy of a VM with the timestamp as a restore point is called a snapshot. Snapshots are taken when an upgrade or software installation is required. For better performance, a snapshot should be removed after a particular task is performed.

82.   How to convert a physical machine into a VM?

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 the difference between a clone and a template?

A clone is a copy of a virtual machine. By cloning a VM, it will save time if multiple VMs with the same configurations are required to configure. While a template is a master copy of an image created from a VM which can be later used to create many clones. After converting a VM to a template, it can’t be powered-on or edited.

84.   What is VDI?

Virtual Desktop Infrastructure where end user physical machine like desktop or laptop are virtualized due to which VMware described VDI as “delivering desktops from the data center”.

85.   What Are Host Profiles?

A set of best practice configuration rules, which are can be applied to entire cluster or to an individual host. So that all the hosts in sync with each other, this will avoid vMotion, drs and ha problems.