Interview Questions on vmware
What are the VMware certifications?
VMware Certified Professional 5 – Infrastructure as a Service (VCP5-IaaS)
VMware Certified Professional (VCP)
VMware Certified Advanced Professional on vsphere 4 (VCAP4)
VMware Certified Advanced Professional on vsphere 5(VCAP5)
VMware Certified Design Expert (VCDX)
VMware Certified Associate (VCA4-DT)
VMware Certified Professional (VCP4-DT)
VMware Certified Professional (VCP5-DT)
VMware Certified Advanced Professional (VCAP-DT)
Tell me something about VMware Company?
VMware is the global leader in virtualization, offering products & solutions for cloud infrastructure and management, cloud application platforms & end-user computing. VMware developed a range of products, most notable of which are their hypervisors. VMware became well known for their first type 2 hypervisor known as GSX. VMware delivered its first product, VMware Workstation. in May 1999 and entered the server market in 2001 with VMware GSX Server (hosted) and VMware ESX Server (hostless).
What are the VMware products?
VMware service manager
Site recovery manager
4) What are the versions of Esx server?
VMware ESX Server 1.0 First release was in 2001
VMware ESX 2.0 (July 21, 2003)
VMware ESX Server 2.5.5 Build 57619 (10/08/2007)
VMware Infrastructure 3.0 (VI3) (June 5, 2006)
VMware ESX Server 3.5 (December 10, 2007)
VMware vSphere 4.0 (May 20, 2009)
VMware ESX 4.1 Build 260247 (July 13, 2010)
VMware ESXi 5.1
VMware ESXi 5.5
VMware ESXi 6.0
5) What are the difference between Esx and Esxi?
Installation time is more.
3rd party Software’s.
5 ways of accessing.
No service console.
Installation time is less.
No 3rd party Software’s.
4 ways of accessing.
Editions Installable and Embedded.
6) What are the Vsphere editions in the 4 and 5?
Same as in Vsphere 4.
8) What are the requirements of an Esx server?
64 bit hardware
2 CPUs min
2 Gb Ram min
1 Gb Nic
VT enable in BIOS
9) What is VApp?
A virtual appliance is a pre-configured virtual machine that typically installs a pre-installed guest operating system and other software.
VApp contains one (or) more related Vm.
In VApp we can set startup and shutdown options.
In VApp we can power on, off and do cloning.
10) What is OVF and OVA, explain the differences?
OVF:- Open Virtualization Format
It contains Vm files.
It exports in the form of directory.
OVA:-Open Virtualization Appliance
It exports in the form of single file, like Zip file
The file contains all the ovf files.
11) What is RDM?
Raw Device mapping
Providing a SAN LUN directly to the Vm is known as RDM.
12) What is an RDM file?
13) What is Thin provisioning and Thick provisioning?
Thin provisioning: – On demand occupying of data store.
Thick provisioning: – It occupies the entire data store.
In thick provisioning there r two types
Eager to Zero:-while creating, the disk is zeroed out.
Lazy to Zero:-while writing the disk is zeroed out.
Eager to zero provides better performance.
14) What is VSMP?
Virtual SMP (Symmetric Multi-Processing) is a utility that allows a single virtual machine to use two or more processors simultaneously.
15) What is the difference between Standard and Distributed switches?
Standard: – Configured at the Host level.
Distributed: – Configured at the VCenter server level.
16) What are host profiles?
A Host profile copy the configuration of a specific host and allows us to duplicate the configuration to other host. It reduces the manual steps in host configuration.
17) What is VMFS? What is its block size in 4 and 5?
VMFS is a cluster file system, which allows multiple hosts to read and write at a time.
Datastore of both is 64TB
Block Size in 4.x (VMFS 3)
Block Size in 5(VMFS 5)
18) Who are the competitors for Esx server?
Red hat enterprise virtualization
19) What is Service console?
Service console is an operating system, which is used to boot Vmkernel and maintains sessions.
20) What is the OS in service console?
Service console is developed based on Red hat Linux operating system.
21) It is based on which Linux version?
Red Hat 7.2 for ESX 2.x and.
Red Hat Enterprise Linux 3 for Esx 3.x.
22) What is default password for Esxi?
The default password in Esxi 4 is Empty.
In Esxi5.0, it is null and we have to assign the password to log into Esxi host through Vsphere client.
23) What is Tech support mode?
Tech support mode is command line interface used to manage the Esx host.
24) How many ways to connect Esx server?
Vsphere client –VCenter
25) How to configure SSh in Esx server?
Log into VCenter server
Configuration tab in right pan.
Security profile in Software.
Click properties for services.
Select SSh and select options.
Select the service want to start.
Click ok. ……
26) What is Port number of SSh?
28) What is diff between Esxi installable and embedded?
Esxi installable comes in Bootable Cd.
Esxi embedded is integrated with the hardware by hardware vendors.
29) I am not able to access Esx server via vsphere client and why?
Login Credentials may be wrong.
Ip address may be wrong.
Ping and check wither its pinging are not.
30) What are the virtual machine files?
31) What is the size of vswp file?
Vswp=allocated memory for Vm – reserved memory for Vm.
32) What is vmdk file?
Virtual machine Hard disk file.
33) What is vmx file?
Vmx is a Configuration file.
It contains Configuration info and H/W sittings of the Vm.
34) My vmx file is corrupted how can I power on the VM
Create a new VM in Custom mode
Match the vmdk file of corrupter vmx and power on.
35) What are the snapshot related files?
.Vmsn—Snapshot –Vm content is stored in these file.
.Vmsd—Snapshot Meta data—Contains info about all snapshots.
.Vmdk—Delta file —Actual storage content is stored.
36) What are the types of network cards available in VM?
39) How many network cards I can configure to VM?
10 cards in 5.0
4 cards in 4.0
40) How can I add hard disk to virtual machine?
Select Hard disk
Create new virtual hard disk
41) What are persistent and non-persistent disks?
Persistent:-If any changes are made to the VM, changes are immediately and permanently written to the disk.
Non-Persistent:-If any changes are made to the VM, changes to the disk are discarded when you power off (or) revert to the snapshot.
42) What is hot add and hot plug?
Hot add means adding Ram to the Vm.
Hot plug means adding Cups to the Vm.
43) What are the storage controllers in VM?
44) What is the max hard disk we can configure to VM?
Max hard disk is 1Tb.
45) What are VMware tools?
VMware tools are nothing but Drivers used for the enhanced performance of the VM (like mouse, keybord, ect.) and used in HA.
46) What is cloning?
Cloning is a technology to create identical copies of an existing VM.
47) What is guest customization?
Guest customization is used to prevent conflicts that occurs at the time of cloning and deploy of Vm (like host name, licences, Sid, time zone ect).
48) What are the requirements for guest customization?
VMware tools must be installed in Vm.
Sysprep file must be installed in VCenter.
49) What is sysprep?
Sysprep files are needed for guest customization to clone a Vm.
50) What is SID?
Secure Id: these are used in Windows operating system to uniquely identify Sys and user.
This option must be selected; else new clone will be same as the parent clone.
51) Can I clone when Vm is powered on?
Yes, we can clone when Vm is powered on, that is known as Hot cloning.
52) Can I clone a Vm from one data center to another and from one VCenter to another?
Yes it possible to clone Vm from one data center to another and from one VCenter to another.
53) What is snap shot (what is meant by consolidating a snapshot)?
Point in time backup of a Vm.
Snapshot allows us to preserve the state of the Vm, so we can return to the same state repeatedly.
Consolidating: – deleting a snap shot before u, so the child content will meagre with the parent.
54) How many snap shots we can configure for VM?
55) Can I clone a Vm from Snap shot?
Yes, we can clone a Vm from snapshot.
56) What are the requirements for installing for VCenter server and what are the supporting Data bases?
64 bit operating system 2k8 or 2k3.
2 Gb Ram min
1 Gb Nic
SQl—-2000 Sp2, 2005 Sp4.
57) What is DSN file?
Data Source Name (DSN) is used to connect the data base of ODBC (open data base connectivity)drives
58) What is linked mode?
Joining two or more VCenter servers is known as Linked mode, so we can view and manage the VCenter.
59) What happens if VCenter server crashes?
DRS will not work.
HA works, but we can’t make changes.
FT works for one failure.
Dvswitch works, but we can’t make changes.
60) What is VSwitch?
VSwitch is software implantation of physical switch. This directs network traffic between Vms and links to external networks.
61) What is Distributed Virtual Switch?
Dvswitch functions as a single switch across all the hosts.
Distributed Virtual switch allows Vm to maintain consistent network configuration as they migrate across multiple hosts.
62) What are the default port groups in Esx and Esxi
Service console port.
VMkernel port (Management port).
Vm port group.
VMkernel port (Management port).
Vm port group.
64) What is Nic teaming?
Connecting multiple physical adapters to a single Virtual switch is known as Nic teaming.
For Failover and Load balancing.
65) What are the failover detection methods?
66) What are the load distribution techniques?
Port based load distribution
MAC based load distribution
IP hash based load distribution
67) What are traffic shaping policies?
68) What are network security policies, and explain each?
MAC address Change.
69) Where do you configure dvSwitch?
In VCenter –>Home–>Inventory–>Networking
Right click on the datacenter–> New Dvswitch
Name, Number of uplink ports
Add host now (or) later, next and next, finish.
70) Is dvSwitch a host specific, cluster, VCs specifics?
Dvswitch is a VCs specific.
71) What are storage protocols Esx supports?
72) What is NFS?
NFS:-Network file system.
NFS is a file sharing protocol that Esxi host used to communicate with storage devices.
76) How can you increase the size of data store?
Configuration tab—storage—right click on Datastore—properties—increase Datastore.
77) What is multipathing, what multipathing available in Esx?
Having multiple paths to an Esx server to connect to the Datastore(SAN)
Fixed or Preferred
Most recently used
78) How do you configure Lun in Esx server?
In Esx click on host add VMkernel port.
Configuration tab–> storage adapter–>add iscsi software adapter.
Details—properties–>Dynamic (or) Static Discovery, give server ip, add Lun path, next.
Storage–>Add storage, partition, next , finish.
79) What is WWN?
WWN is World Wide Name, it is a naming convention used for the Lun, when we use HBA. (Fibre channel cable)
80) What is IQN?
IQN is Iscsi Qualified Name, it is a naming convention used for the Lun, when we use iscsi hardware or iscsi software. (Ethernet cables)
81) What is zoning?
Dividing Fc switch into different zones for providing security to host before connecting to San Datastore.
82) What is Lun masking?
Exposing one more Lun to a specified host is known as Lun masking.
83) What is Vmotion
Migrating Vm’s from one host to another host without downtime.
For maintenance and load balancing.
84) What are the Pre requisites of Vmotion?
Vm’s should be in shared data store.
Vmotion should be enabled in VMkernel port.
No locally attached devices.
Both Esx must have same Network configuration.
85) What is SVmotion?
Migrating Vm’s from one data store to another data store is known as Svmotion.
86) Prerequisites of SVmotion?
Same of Vmotion.
87) What is a cluster?
A cluster is a collection of Esx servers and its associated Vm’s.
88) What is EVC?
Enhanced Vmotion compatibility which prevents Vmotion migration from failing because of Cpus incompatibility.
89) What are the pre requisites for EVC?
The Cpus must be from same vendor.
Esx 3.5 update 2 or Later.
Connected to VCenter.
Enable Hardware virtualization.
Configure to Vmotion migration.
90) Why would one change the swap file location of VM?
Moving the swap file to an alternate location can be done to lower the cost or higher performance storage or non-replicated storage for disaster recovery solution.
VMware recommends to store the Swap file in the same directory as Vm.
91) What is DRS
DRS (distributed resource scheduler ) Automatic distribution of Vm from one Esx serve to another Esx is known as DRS.
92) What is DPM?
DPM (distributed power management) places host in standby for optimize power usage.
93) What are the DRS automation modes and rules?
Vm – Vm Affinity
Vm-Vm Anti affinity
94) What is HA?
HA (High Availability) is a host level feature which restarts the Vm’s to other Esx servers in case of host failure.
95) What is Admission control policy?
Admission control policy helps ensure sufficient resources to provide High Availability.
Admission control policies:-
Host failures the cluster tolerates.
Percentage of cluster resources reserved as failover spare capacity.
Specify failover Hosts.
96) How many host failures cluster tolerates?
4 Host failures.
97) What is a slot
A slot is a logical representation of the memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the cluster.
98) What are the slot sizes
Max usages of Cpu and Memory reservations of the Vm.
If no reservations then the default of 256 MHz for Cpu and Memory overhead for Memory is used.
99) What is host isolation?
Host Isolation response determines what happens to the Vm’s when host loses the network heartbeat but continues running.
100) Responses available?
Leave power on
Use cluster settings
101) what is HA restart priority?
HA restart priority determines which Vm should power on firs.
102) Can I stop a single VM to restart?
103) what is HA for VM?
HA agent monitors VMware tools in each Vm running on the host and if it doesn’t receive heartbeat, it restarts the Vm on the same host.
104) what is HA agent?
In 5.0 HA agent is FDM (Fault domain manager)
In 4.1 AAM (Automatic availability manager )
When HA is enabled, it automatically installed in Esx and monitors it.
105) what are HA logs?
If managed by vCenter Server 5.0 or later – /var/log/vmware/fdm/*
If managed by vCenter Server 4.1 or earlier – /var/log/vmware/aam/*
106) what are the requirements for HA?
Min 3 GB ram for Esx.
Name resolution should be resolved.
107) what is FT?
Fault Tolerance provides zero down time, zero data loss and continues availability of the applications.
108) what are the requirements of Fault Tolerance?
Vm should be in shared Datastore.
Single Vcpu for Vm.
Hardware virtualization should be enabled in BIOS.
3 nic’s of minimum of 1GB.
Cpus must mach and be from a specific list of processors.
Only 4 ft enabled Vm in a single Esx.
109) what is fixed baseline and dynamic base line?
Fixed Patch Baseline: – In this type of base line, you manually specify which patches to include in the fixed patch baseline from the total set of patches available in the Update Manager repository.
Dynamic patch Baseline: – The contents of a dynamic baseline are based on available patches that meet the specified criteria. As the set of available patches changes, dynamic baselines are updated as well. You can explicitly include or exclude any patches.
110) in how many ways can you upgrade Esx server and How?
You can upgrade Esx server in 3 ways:
Insert the advanced version of Esx server Cd into the drive and reboot the system, it will ask you to upgrade the server.
By using patches (update manager installed, connected to VCS)
By using ISO image of the advanced version(update manager installed and connected to VCS)
111) how do u upgrade VCenter server?
Let us discuss the case of upgrading VCenter server from 4.1 to 5.0
While installing the VCS 4.1 you will be asked to give the data source name. DSN is used to establish the connection to the data base. Give the DSN by using native client. Preserve that DSN name safely.
Install multiple ESX and VM’s in the VCS.
Again install VCS5.0 in any of the machines and use the same DSN as used while installing 4.1.
Make sure you copy the SSL certificates to the new server folder.
Crash or power of the 4.1 machine
Login to the machine of 5.0, you can see the ESX servers and VM’s running in it.
112) How to upgrade VM hardware?
Login to VCenter server via Vsphere client or web client
Power off the VM
Right click on the VM, menu option
Upgrade Hardware and yes
Power on the VM
113) what are the Virtual machine hardware versions in 3.5, 4.0 and5?
The Hard ware version in:-
Esx3.5 is 4
Esx /Esxi 4.0 is 7
Esxi5.0 is 8
115) what are operating systems that support hot add and hot plug?
Windows 2003 server 32 bit enterprise edition.
Windows 2003 server 64 bit enterprise edition.
Windows 2008 server 32 bit
Windows 2008 server 64 bit
Windows 7 Enterprise and Ultimate 64-bit
116) what is P2V and v2v?
Converting a Physical machine to a virtual machine is called as P2V
Converting a Virtual machine to a virtual machine is called as v2v (VM’s running on a Work Station).
117) in how many ways can we convert p2v?
There are 3 ways to P2V:-
Bootable Cd or Ghost imaging process.
VMware converter standalone.
VMware converter integrated with VCenter.
118) what are the default installed plugins in VCenter server
VMware VCenter storage monitoring.
VCenter hardware status.
VCenter Service status.
122) what is VShield edge and vcd?
Provides protection to the Datastore.
123) what is VMA?
The vsphere Management Assistant (VMA) allows administrators and developers to run scripts and agents to manage Esxi hosts and VCenter Server systems. VMA is a virtual machine that includes pre-packaged software, a logging component, and an authentication component that supports non-interactive login.
124) what is VCLI?
The vsphere Command-Line Interface (vsphere CLI) command set allows you to run common system administration commands against ESX/Esxi systems from any machine with network access to those systems. You can also run most vsphere CLI commands against a VCenter Server system and target any ESX/Esxi system that VCenter Server system manages. Vsphere CLI includes the ESXCLI command set, vicfg- commands, and some other commands.
125) what is PowerCLI?
VMware vsphere PowerCLI is a powerful command line tool that lets you automate all aspects of vsphere management, including network, storage, VM, guest OS and more. PowerCLI is distributed as a Windows PowerShellsnap in, and includes more than 300 PowerShell cmdlets, along with documentation and samples.
126) what is DCUI?
DCUI: Direct console user interface. The Esx/Esxi screen.
127) what is EULA?
EULA: End user License agreement is the contract between the licensor and purchaser, establishing the purchaser’s right to use the software.
128) what is Resource pool?
A Resource pool is a logical aggression of resources (like cpu and memory )
Managing CPU and memory resources.
129) what are reservations, limits and expandable reservations?
Reservations: – The minimum amount of resources that are required by the resource pool. For example, you can set a CPU reservation, which is the minimum amount of CPU that this pool must have.
Limits: – The maximum amount of resources that are given to the resources pool. By default, the resource pool is given “unlimited” access to the maximum amount of resource.
Expandable Reservation: -An attribute that is specific to a resource pool. This attribute allows a resource pool that cannot satisfy a reservation request to search through its hierarchy to find unreserved capacity to satisfy the reservation request.
130) what are Shares in Resource pool?
Shares:-It guarantees certain amount of resources to resource pool (like Cpu and Memory).shares work like virtual machine shares.
131) what is memory over commitment?
Memory over commitment occurs when physical memory allocated to the host is less than the sum of memory allocated to the virtual machines.
132) what are the memory reclamation techniques and explain each one of them?
Transparent page sharing: -Transparent page sharing allows pages or files with identical contents to be stored once.
Memory ballooning mechanism: – It is active when memory scarce, forces Vm’s to use their own paging area. VMware tools start an App called as Balloon drivers and that memory is given to the needed Vm.
Memory compression: -Esx compresses pages in Ram only. Memory compression is another technique that the VMkernel uses to reclaim host physical memory. This technique attempts to reclaim some memory by compressing pages.
Hypervisor Swapping: – The Esx server swaps least used pages to the Hard disk. This technique is used to page virtual machine memory to disk. This is used when other techniques are temporarily unable to reclaim memory quickly enough to satisfy current system demand.
133) how do you monitor the performance of ESX and VM?
Monitoring the Performance of ESX: – When you connect to ESX server, you can see the performance tab on the screen, it displays the chart and graphs of the Esx server.
Monitoring the Performance of VM: – Click on Vm, performance tab.
134) what is ESX top?
ESXTOP is a tool often used at VMware to diagnose and identify performance problems.
135) what is the difference between Esx top and resx top?
The fundamental difference between resx top and Esx top is that you can use resx top remotely, where as you can start Esx top only through the service console of a local Esx host.
140) what are Esx log files?
/var/log/vmkernel – Core VMkernel logs, including device discovery, storage and networking device and driver events, and virtual machine startup.
/var/log/vmkwarning – Summary of Warning and Alert log messages excerpted from the VMkernel logs.
/var/log/vmksummary – Summary of ESX host startup and shutdown, and an hourly heartbeat with uptime, number of virtual machines running, and service console resource consumption.
/var/log/messages – Messages from the Service Console Linux kernel, including service startup and shutdown.
/var/log/vmware/hostd.log – Host management service logs, including virtual machine and host Tasks and Events, communication with the vsphere Client and VCenter Server vpxa agent, and SDK connections.
/var/log/boot-logs/sysboot.log – Early VMkernel startup, module loading, and host initialization.
/var/log/vmkiscsid.log – Software iscsi Client logs.
141) what are VCenter server log files?
When an ESX host is managed by VCenter Server, two components are installed, each with its own logs:
/var/log/vmware/vpx/vpxa.log – VCenter Server vpxa agent logs, including communication with VCenter Server and the Host Management hostd agent.
VMware High Availability logs:
If managed by VCenter Server 5.0 or later – /var/log/vmware/fdm/*
If managed by VCenter Server 4.1 or earlier – /var/log/vmware/aam/*
143) what is vpxa, vpxd, hostd?
Hostd: -The hostd process runs directly on the Esxi host and is responsible for managing most of the operations on the Esxi host.
Vpxd: -Vpxd is a process which runs on the VCenter server.
Vpxa: -Vpxa is a VCenter agent. It acts as an intermediary between vpxd and hostd.
144) How to restart vpxa?
Service vmware-vpxa restart (or to stop, start)
145) How to restart management agents in Esx and Esxi?
Esx:- service mgmt-vmware restart(or to stop, start)
Esxi: – DCUI–>F2–>Restart management agent.
146) what is the difference between HA mechanism in 4 and 5?
HA in 4.0: -Only Network heartbeat is present, Primary and secondary hosts (5 primaries are always present). No Datastore heartbeat.
HA in 5.0:- Network heartbeat and Datastore heartbeat are present, Master and slaves. Only one Master and remaining are slaves.
147) what is FDM?
FDM (Fault domain manager) is HA agent that starts on the hosts when HA is enabled.
148) what is Datastore heartbeat?
The Datastore heartbeat is used to make the communication between a master and failed or Isolated or partitioned host.
149) what are the services in VCenter server?
VMware VCenter Orchestrator configuration
VMware Virtual center Management Web services
VMware Virtual center Server
VMware vsphere Profile Driven Storage service
154) what is a template?
Template is also a virtual machine which cannot be powered on.
155) when virtual machine is converted to template what are the files which get changed?
Vmx file get changed to vmtx
157) what are the default roles available in VCenter server and what is no access role and explain when it is used?
Default Roles Available:-
158) to install VCenter server which one is preferred (Physical machine or Virtual machine) and why?
It prefer to install VCenter server in a virtual machine, even if the hardware fails also there will be no problem and it does not affect the Vm.
159) what is the command used to keep ESX server in maintenance mode?
esxcfg – hostops –operation enter
160) what is the command used to exit ESX server from maintenance mode?
161) what is the command used to create a VSwitch?
esxcfg –vswitch –a vSwitch0
In the above command I have created a virtual switch name vswitch0
162) what is the command used to create a port group?
esxcfg -vswitch-add-pg iscsi -l vSwitch0
163) what is the command used to create a service console port?
esxcfg-vswitch –A “Service Console” vSwitch0
166) what is the command used to create a vmdk file?
Here in this command to created a virtual machine file of 10GB:
Vmkfstools –c 10GB 167) what is the command used to extend vmdk file?
Here in the command, to extend the vmdk file with 10GB file, now my total file size would be 20GB.
Vmkfstools -X 10GB 168) what is the command used for Svmotion?
It Moves a virtual machine configuration file and optionally its disks while the virtual machine is running.
The below command prompts you for the information it needs to complete the storage migration.
169) what is the command used for update patches?
The command used to configure only to download the host patch is:
Vmware –umds.exe–set-config -enable host1 -enable win0 -enable
The command used to start the download patch is:
Vmware –umds.exe -download
To set the path where the patches to be stored:
Vmware –umds.exe -set-config –path c: \download
171) what is the command used to unregister a virtual machine?
The following command is used to unregister the virtual machine from the inventory
172) what is the command used to list all the network cards?
esxcfg –nics -l
173) what is the command used to change the default gateway?
Esxcfg –route –a 192.168.100.0/24 192.168.0.1