VMware Top 80 VMWare Interview Questions and Answers

VMware

Top 80 VMWare  Interview Questions and Answers

Q:  Mention what is VMware and what are their benefits?

VMware provides different applications and software for virtualization.  VMware products are categorized in two levels, desktop applications, and Server applications.  It is useful for

• Running multiple operating systems and applications on a single computer
• Consolidate hardware to get vastly higher productivity form fewer servers
• Save more than 50% of total cost spend on IT
• It simplifies IT management and speed up the deployment of new applications

Q:  Mention what are the different types of virtualization available?

Different types of virtualization available are

• Application virtualization
• Presentation virtualization
• Network virtualization
• Storage virtualization

Q:  What is virtualization?

Virtualization is a proven software technology that makes it possible to run multiple operating systems and applications on the same server at the same time. It’s transforming the IT landscape and fundamentally changing the way that people utilize technology.

Q: What do you understand by Virtual Machine?

A virtual computer systems 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”.

Q: What are the key properties of a Virtual Machine?

1 Partitioning
Run multiple operating systems on one physical machine
Divide system resources between virtual machines

2. Isolation

Provide fault and security isolation at the hardware level

Preserve performance with advanced resource controls

3.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

Q:  Mention what are the different types of server software does VMware provides?

VMware provides three different types of server software

1.  VMware ESX Server

2.   VMware ESXi Server

3.   VMware Server

Q:  Explain what is hypervisor?

Hypervisor is a program that enables multiple operating systems to share a single hardware host.  Each operating system has the host’s processor, memory and other resources all to itself.  Hypervisor controls the resources and host processor, allocating what is required for each operating system in turn and make sure that the guest operating system cannot disrupt each other.

Q:  Explain what is VMware DRS?

VMware DRS stands for Distributed Resource Scheduler; it dynamically balances resources across various host 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.

Q:  How VMWare Kernel different from other kernels?

VMWare kernel is a proprietary kernel that means that it is a registered kernel by VMWare Company and it is not based on any other kernel architecture or any other operating system. VMWare consists of a kernel that requires an operating system to boot it. A service console is being provided when VMWare kernel is booted.

Q:  What are the features provided by VMWare for easy access?

VMWare provides several features to make it easy for the user to access and maintain it. The features are as follows:
1 VMWare provides web browser interface
2 It provides easy to use wizard to configure the settings
3 It provides tools to easily create hosts and maintain it from one place
4 It provides easy maintenance of Virtual machines
5 It provides easy graphics to configure the VMWare settings for security

Q:  To restart webaccess service on vmware

service vmware-webaccess restart – this will restart apache tomcat app

Q:  To restart ssh service on vmware
service sshd restart

Q:  To restart host agent(vmware-hostd) on vmware esx server
service mgmt-vmware restart

Q:   Path for the struts-config.xml
/usr/lib/vmware/webAccess/tomcat/apache-tomcat-5.5.17/webapps/ui/WEB-INF/

Q:  What is Data Store?
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.

Q:  What is VMware DRS?

VMware DRS stands for Distributed Resource Scheduler; it dynamically balances resources across various host 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.

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

 Q:  What is VMware DPM?
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.

Q:   Explain VMware Fault Tolerance?

VMware fault tolerance is an important component of VMware vSphere, and it offers continuous accessibility to applications by preventing data loss and down time of virtual machines in the event of ESX server failure.

Q: Mention what is FT logging traffic?

FT logging is one of the options in VMKernel port setting which is more or less same as enabling vmotion option in the vmkernel port.

Q:  What are the features of VMWare Player?

VMWare player is a stand-alone player that comes with the installation of VMWare also. The features that make it more popular are as follows:

– Creation of virtual machines can be done with easy install options. The creation and installation can be done directly to the system.
– VMWare Player can run any virtual machine and it can be used by anyone, anywhere. It allows quick and easy access, to take the advantage of security, portability and flexibility to manage the virtual machines.
– VMWare player allows sharing of virtual machines with other computers or users.

Q:  What are the different components used in VMWare infrastructure?

The different and major components used in VMWare infrastructure is as follows:

1. VMWare infrastructure consists of the lowest layer which acts as a ESX server host.
2. VMWare infrastructure also use the virtual centre server that keep tracks of all the VM related images and manage it from one point.
3. VMWare infrastructure (VI) client: this allows the client to interact with user’s applications that are running on VMWare.
4. Web browser is used to access the virtual machines.
5. License server is used to create a server that provides licensing to the applications
6. Database servers are used to maintain a database.

Q:  What are the benefits of virtualization?

Virtualization is a creation of virtual machines and to manage them from one place. It allows the resources to be shared with large number of network resources. Virtualization is having lots of benefits and they are as follows:

1. It helps in saving lots of cost and allows to easily maintaining it, in less cost.
2. It allows multiple operating systems on one virtualization platform.

3.  It removes the dependency of heavy hardware to run the application.

4. It provides consolidating servers that are used for crashing of a server purpose

5. It reduces the amount of space being taken by data centres and company data.

Q:  When you visit certain Web sites, the request is “connection was reset” the report, then what is the principle of connection is reset?
The nature of the connection is reset, because it has received a TCP Reset packet damage connected

Q:   VMware ESX is still providing support for the architecture?
VMware will follow VMware vSphere support policy to continue to provide technical support for ESX architecture.

Q:  What are the three port groups present in ESX server networking

1.  Virtual Machine Port Group – Used for Virtual Machine Network
2.  Service Console Port Group – Used for Service Console Communications
3.  VMKernel Port Group – Used for VMotion, iSCSI, NFS Communications

Q:  What is the use of a Port Group?
The port group segregates the type of communication.

Q:  What are the type of communications which requires an IP address for sure ?
Service Console and VMKernel (VMotion and iSCSI), these communications does not happen without an ip address (Whether it is a single or dedicated)

Q:  In the ESX Server licensing features VMotion License is showing as Not used, why?
Even though the license box is selected, it shows as “License Not Used” until, you enable the VMotion option for specific vSwitch

Q:  How the Virtual Machine Port group communication works ?
All the vm’s which are configured in VM Port Group are able to connect to the physical machines on the network. So this port group enables communication between vSwitch and Physical Switch to connect vm’s to Physical Machine’s

Q:  What is a VLAN ?
A VLAN is a logical configuration on the switch port to segment the IP Traffic. For this to happen, the port must be trunked with the correct VLAN ID.

Q:   Does the vSwitches support VLAN Tagging? Why? 
Yes, The vSwitches support VLAN Tagging, otherwise if the virtual machines in an esx host are connected to different VLANS, we need to install a separate physical nic (vSwitch) for every VLAN. That is the reason vmware included the VLAN tagging for vSwitches. So every vSwitch supports upto 1016 ports, and BTW they can support 1016 VLANS if needed, but an ESX server doesn’t support that many VM’s.

Q:  What is Promiscuous Mode on vSwitch ? What happens if it sets to Accept?

If the promiscuous mode set to Accept, all the communication is visible to all the virtual machines, in other words all the packets are sent to all the ports on vSwitch
If the promiscuous mode set to Reject, the packets are sent to inteded port, so that the intended virtual machine was able to see the communication.

Q:  What is MAC address Changes ? What happens if it is set to Accept ?
When we create a virtual machine the configuration wizard generates a MAC address for that machine, you can see it in the .vmx (VM Config) file. If it doesn’t matches with the MAC address in the OS this setting does not allow incoming traffic to the VM. So by setting Reject Option both MAC addresses will be remains same, and the incoming traffic will be allowed to the VM.
Q: Mention what are the different components used in VMware infrastructure?

    Different components used in VMware infrastructure includes

• It consists of the lowest layer which acts as an ESX server host
• It also uses the virtual center server which keep tracks of all the VM associated images and manage it from one point
• VMWare infrastructure client, it enables the client to communicate with user’s applications that are running on VMware
• Web-browser is used to access the virtual machines
• License server is used to prepare a server which provides licensing to the applications
• Database servers are availed to maintain a database

Q:   Explain what is vCloud Suite?

vCloud Suite combines with multiple VMware components to give a complete set of cloud infrastructure capabilities in a single package, including virtualization, software-defined datacenter services, disaster recovery, application management, etc.

Q:   Mention what are the storage and availability in vCloud Suite?

The storage and availability in vCloud Suite includes

Storage DRS: It place and load balance virtual machines based on storage capacity and I/O latency

Storage vMotion: It employs proactive, non-disruptive storage migration to reduce virtual machine storage I/O bottlenecks and free up valuable storage capacity

Application HA: It gains high availability that is bound to specific applications

Data Protection: Based on EMC avamar, it deploys a back-up and recovery tool

Q:  Explain what is Host Isolation in VMware HA (High Availability)?

In VMware HA, it has a mechanism to detect a host isolated from the rest of hosts in the cluster.  In simple words, it uses a heart-beat to communicate other host in the cluster. When the ESX host loses its ability to connect with other hosts in a cluster through heart-beat, then ESX host will be considered as a Host Isolation.

Q:  Mention what is the difference between VMware HA and Vmware FT?

VMware FT is enabled per VM basis while VMware is enabled per cluster

In the case of ESX host failure, virtual machines are the failed host and are re-started and powered-on the other active hosts in HA cluster. But FT enabled virtual machines; there is no down time. In the case of host failure, secondary VM will be activated, and it becomes primary and continue to run from the exact point where the primary VM is failed or left off.

Q:  Explain the new features available in vSphere 5?

In the latest version of vSphere 5.5 it includes

• ESXi Hypervisor enhancement
• Virtual Machine Enhancement
• VMware vCenter Server Enhancement
• vSphere storage Enhancement
• vSphere Networking Enhancements

Q:   How can I evaluate VMware vSphere?
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 .

Q:  When using the ESXi architecture, Update Manager whether to repair my vSphere host?
VMware vCenter Update Manager will be updated to run ESXi host. In addition to VMware Update Manager environment provides not installed the update utility.

 Q:  What is the ESXi Shell?
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.

 Q:   What are the advantage and disadvantages of VMWare workstation?
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 simple interface for users of various fields of computer!

 Disadvantages:

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

 Q: Can we do vMotion between two datacenters ? If possible how it will be?
Yes we can do vMotion between two datacenters, but the mandatory requirement is the VM should be powered off.

Q:  What is the purpose of a Hypervisor?

Hypervisor is a program that manages the virtual machine. It also act like virtual machine manager that manages the many virtual machines from one place. It allows multiple operating system to share single hardware host. Each operating system in this consists of its own defined space consisting of space, memory and processor. It is used as a controller program to control host processors and resources. It separates out the layer between many operating systems so that one can’t conflict with another one.

Q:  How ESX server related to VMWare?

      ESX server is the enterprise edition of VMWare. It provides server virtualization platform that allows many operating systems to be shared together in a convenient way and consists of a centralized management platform that is also known as virtual centre. ESX server is a virtualization technique that is used to create cloud applications and allows easy development of cloud platforms. It is related to VMWare as it is the upper layer of it.

Q:   What is Forged Transmits ? What happens if it is set to Accept ?

When we create a virtual machine the configuration wizard generates a MAC address for that machine, you can see it in the .vmx (VM Config) file. If it doesn’t matches with the MAC address in the OS this setting does not allow outgoing traffic from the VM. So by setting Reject Option both MAC addresses will be remains same, and the outgoing traffic will be allowed from the VM.

Q:   What are the core services of VC ?

VM provisioning , Task Scheduling and Event Logging

Q:  Can we do vMotion between two datacenters ? If possible how it will be?

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

Q:   What is VC agent? and what service it is corresponded to? What are the minimum req’s for VC agent installation ?

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 agent installed on the ESX server when we add it to the VC, so at the time of installtion if you are getting an error like ” VC Agent service failed to install “, check the /Opt size whether it is sufficient or not.

Q:   How can you edit VI Client Settings and VC Server Settings ?

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

Q:   What are the files that make a Virtual Machine  ?

.vmx – Virtual Machine Configuration File
.nvram – Virtual Machine BIOS
.vmdk – Virtual Machine Disk file

.vswp – Virtual Machine Swap File
.vmsd – Virtual MAchine Snapshot Database
.vmsn – Virtual Machine Snapshot file
.vmss – Virtual Machine Suspended State file
.vmware.log – Current Log File
.vmware-#.log – Old Log file

Q:  What are the new features included in ESXi Hypervisor enhancement?

In ESXi Hypervisor enhancement includes

• Hot-pluggable PCIe SSD Devices: It supports SSDs (Solid State Disks) devices, and with a new enhancement, SSD device can be removed or added while a vSphere host is running.
• Support for Reliable Memory Technology: vSphere ESXi hypervisor can take an advantage of new hardware; vendor enabled Reliable Memory Technology, through which a region of memory is reported from the hardware to vSphere ESXi hypervisor. It is used to enhance the placement of VMKernel and other components like initial thread and hostd. It helps to protect against memory error
• Enhancements to CPU C-states: A power process (C-state) is used to provide additional power savings

Q:    What are the devices that can be added while the virtual Machine running

In VI 3.5 we can add Hard Disk and NIC’s while the machine running.
In vSphere 4.0 we can add Memory and Processor along with HDD and NIC’s while the machine running

Q:   How to set the time delay for BIOS screen for a Virtual Machine?

Right Click on VM, select edit settings, choose options tab and select boot option, set the delay how much you want.

Q:  What is a template ?

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

Q: What to do to customize the windows virtual machine clone,?

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

Q:  What to do to customize the linux/unix virtual machine clone,?

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

Q:  Does cloning from template happens between two datacenters ?
Yes.. it can, if the template in one datacenter, we can deploy the vm from that template in another datacenter without any problem.

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

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

Q:   What are the settings that are taken into to consideration when we initiate a snapshot ?

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)

Q:  What are the requirements for Converting a Physical machine to 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

Q:   What is VMWare consolidated backup ?

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

Q:  What are the types of data stores supported in ESX3.5 ?

iSCSI datastores, FC SAN datastores, Local VMFS, NAS and NFS

Q:   How can you configure these different types of datastores on ESX3.5 ?

If we have FC cards installed on the esx servers, by going to the storage option, we can scan for the luns.

Q: What is Vmware Consolidate Backup (VCB) ? Explain your work exposure in this area ?

VMware Consolidated Backup is a backup framework, which enables 3rd party tools to take backups. VCB is used to help you backup your VMware ESX virtual servers. Essentially, VCB is a “backup proxy server”. It is not backup software. If you use VCB, you still need backup software. It is commonly installed on its own dedicated Windows physical server.

Here are the benefits of VMware’s VCB:
Centralize backups of VMware ESX Virtual Servers
Provide file-level backups of VMware ESX Virtual Servers – both full and incremental (file level backup available to only Windows guests)
Provide image-level backups
Prevent you from having to load a backup agent on every Virtual Machine
Prevent you from having to shutdown Virtual Machines to get a backup
Provides LAN-Free backup because the VCB server is connected to the SAN through your fibre channel adaptor
Provides centralized storage of Virtual Server backups on the VCB server, that is then moved to your backup tapes through the 3rd party backup agent you install
Reduces the load on the VMware ESX servers by not having to load a 3rd party backup agent on either the VMware ESX service console or on each virtual machine.
Utilizes VMware Snapshots
Basically, here is how VCB works:
If you are doing a file level backup, VCB does a snapshot of the VM, mounts the snapshot, and allows you to backup that mounted “drive” through VCB to your 3rd party backup software
If you are doing an image level backup of the VM, VCB does a snapshot of the VM, copies the snapshot to the VCB server, unsnaps the VM, and allows you to backup the copied snapshot image with your 3rd party backup software.

Q:  What is the difference between ESX and GSX server?

GSX server acts as type 2 hypervisor that gets installed on the host operating system’s hardware like windows and  Linux. VMWare workstation gets mixed up with GSX server to provide it more functionality to run your applications  and operating systems. ESX server on the other hand, is type 1 hypervisor that runs its software directly on the system’s hardware and it doesn’t require any operating system prior to its installation. It is level 0 hypervisor and it has its own operating system.

Q:  What is the use of VMWare workstation?

VMWare workstation is software that allows user to run more than one operating system in there system. It provides virtualization to run different applications on many operating systems at a single time. It saves the current configuration of operating system for the user in the form of virtual machines. VMWare allows user to view there application and work with so many different OS without even switching between the OSs.

Q:  What are the different types of extensions used by VMWare?

1. .log: is used to keep a log file to maintain a key for VMWare. This file allows user to see the problems encountered during any installation or while using VMWare.
2. .nvram: is used to store the state of the virtual machine in system’s BIOS.
3. .vmdk: is a virtual disk file that is used to store the content of virtual machine.
4. .vmsd: stores the information and metadata of the system’s snapshots.
5. .vmsn: is used to store the snapshot state. It stores both the running state and the time when you have taken it.
6. .vmss: stores the suspended state of a virtual machine.
7. .vmtm: stores the configuration team data.
8. .vmx: store the primary configurations for the new virtual machine.

Q:  How virtual machine’s concept is different for host and guest systems?

Host system is the system that runs the operating system and over which the virtual platform can be installed. The virtual platform that runs another operating system is called as guest operating system. Host and guest can be connected with each other by using the virtual machines. A host system that runs all together its own operating system is called as virtualization host and the guest operating system will be that, which get installed over that operating system.

Q:  What are some major differences between VMWare Server and ESX server?

– ESX server is a bare metter virtualation platform that is a physical server whereas, VMWare server needs an operating system to run itself.

– ESX server is type 1 hypervisor virtualization platform whereas, VMWare server is a type-2 hypervisor virtualization platform.

– ESX server gives better performance then VMWare server, due to less overhead.

– ESX server have more features available then VMWare server.

– VMWare server is good to be used on small platforms and with less resources but, ESX server requires high specifications.

Q:  What is the use of Para-virtualization?

Para-virtualization is a virtualization technique that allows similar virtual machines to be created on particular hardware. It allows many operating systems to run on host hardware at the same time. It makes good use of resources like processors, memory and networking. It acts as a virtual machine monitor that has high performance and more efficient. It is used for development, testing and production of the virtual machines. It also good in disaster recovery by moving the guest virtual machine till the hardware is being repaired.

Q:   What are the devices that can be added while the virtual Machine running

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

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

Q:   How to set the time delay for BIOS screen for a Virtual Machine?

Right Click on VM, select edit settings, choose options tab and select boot option, set the delay how much you want.

Q:  What is a template ?

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

Q:  What to do to customize the windows virtual machine clone,?
copy the sysprep files to Virtual center directory on the server, so that the wizard will take the advantage of it.

Q:  What to do to customize the linux/unix virtual machine clone,?

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