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.
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: • VMWare provides web browser interface
• It provides easy to use wizard to configure the settings
• It provides tools to easily create hosts and maintain it from one place • It provides easy maintenance of Virtual machines
• It provides easy graphics to configure the VMWare settings for security
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.
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.
5. 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.
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.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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.
12. 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.
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.
13. 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.
14. Why snapshots are really important in VMWare?
Snapshots are images that is been taken at a particular point from the virtual guest operating system. The snapshot consists of the virtual machine configurations, memory and the devices that were present at the time of the snapshot. By doing this, you can return back to virtual machine which might have become corrupted or might not be working. Snapshots can be taken anytime according to your need and requirement. Snapshots can be saved and then system can be reverted back in case of any disaster happened to your operating system.
15. What are the disadvantages associated with VMWare virtualization platform?
The disadvantage of VMWare virtualization platform is as follows: • VMWare concept requires the knowledge of the concept.
• It requires money to buy the resources required for virtualization platform.
• It requires high end server with lots of high end configuration and specification that increases the cost. • It requires different technologies that have to be implemented for the enterprise virtualization systems. • Reliability decreases and cost increases in case of the system failures.
101 VMware & Windows Interview Questions : Part 1
1. Windows 2003 vs Windows 2008
o
RODC
o
WDS instead of RIS
o
Services have been changed as roles - server manager
o
Introduction of hyper V- only on 64 bit versions
o
Enhanced event viewer
o
Bitlocker feature
o
Server core installation without GUI
o
MMC 3.0, with three pane view
o
Key management services(KMS) to activate Windows OS without connecting to
Microsoft site
o
Performance enhancement using technologies like Windows SuperFetch,ReadyBoost
and Readydrive
o
Windows Aero user interface
o
Instant search
o
Support for IPv6 in DNS
2.
ESX vs ESXi
o
ESXi has no service console which is a modified version of RHEL
o
ESXi is extremely thin hence results in fast installation + fast boot
o
ESXi can be purchased as an embedded hypervisor on hardware
3.
ESXi 4.1 vs ESXi 5.0 - Migration
o
Local upgrade from CD
o
VMware update manager (only supports upgrade of ESX/ESXi 4.x to ESXi 5.0)
4.
ESXi 4.1 vs ESXi 5.0 - Features
o
vSphere Auto deploy
o
Storage DRS
o
HA - Primary/secondary concept changed to master/slave
o
Profile driven storage
o
VMFS version - 3 → 5
o
ESXi firewall
o
VMware hardware version - 7 → 8
o
VMware tools version - 4.1 → 5
o
vCPU - 8 → 32
o
vRAM - 256 → 1 TB
o
VMs per host - 320 → 512
o
RAM per host - 1TB → 2TB
o
USB 3.0 support
o
vApp
5.
FSMO roles
o
Schema Master
o
Domain naming master
o
PDC Emulator
oRID master
6.
GPO
oGPO
oTemplates (ADMX)
oBlock inheritance
oEnforced
oLoopback policy
7.
Forest and Domain concepts
8.
OSI layer
oApplication Layer
oPresentation Layer
oSessions Layer
oTransport Layer
oNetwork Layer
oDataLink layer
oPhysical Layer
10.
HA 5.0
o
Uses an agent called FDM - Fault domain manager
o
HA now talks directly to hostd instead of using vcenter agent vpxa
o
Master/slave concept
o
Master
monitors availability of hosts/VMs
manages VM restarts after host failure
maintains list of all VMs in each host
restarting failed VMs
exchanging state with vcenter
monitor state of slaves
o
Slave
monitor running VMs and send status to master and performs restart on
request from master
monitors master node health
if master fails, participates in election
o
Two different heartbeat mechanisms - Network heartbeat and datastore heartbeat
o
Network heartbeat
Sends between slave and master per second
When slave is not receiving heartbeat from master, checks whether it is
isolated or master is isolated or has failed
o
Datastore heartbeat
To distinct between isolation and failure
Uses „Power On‟ file in datastore to determine isolation
This mechanism is used only when master loses network connectivity with
hosts
2 datastores are chosen for this purpose
o
Isolation response
PowerOff
Leave Powered On
Shutdown
11.
vMotion
o
vMotion enables live migration of running virtual machines from one host to another
with zero downtime
o
Prerequisites
i.
Host must be licensed for vMotion
ii.
Configure host with at least one vMotion n/w interface (vmkernel port group)
iii.
Shared storage (this has been compromised in 5.1)
iv.
Same VLAN and VLAN label
v.
GigaBit ethernet network required between hosts
vi.
Processor compatibility between hosts
vii.
vMotion does not support migration of applications clustered using Microsoft
clustering service
viii.
No CD ROM attached
ix.
No affinity is enabled
x.
vmware tools should be installed
12.
RAID
o
Redundant Array of Independent disks
o
A category of disk drives that uses 2 or more drives in a combination for redundancy
and performance
o
Most common RAIDs: RAID 0(Striped), RAID 1(Mirroring), RAID 5
13.
Backup types
oBackup types
i.
Full backup - Will take the backup of all selected files and reset the archive
bit
ii.
Copy backup - Will take the backup of all selected files but does not reset the
archive bit
iii.
Incremental backup - Will take the backup of files whose archive bits are set
and resets it after backup
iv.
Differential backup - Will take the backup of files whose archive bits are set
but does not reset it after backup
14.
2003 → 2008 migration
o
Can be done only by logging in to Windows 2003 server
o
Min of Windows 2003 SP1 required
o
Can be migrated only to same version, except for Windows server 2003 standard
which can be migrated to either standard or enterprise
o
Extra space of 30 GB required prior migration
o
Cannot upgrade to server core
o
Perform forestprep and domainprep to 2008 using 2008 cd before migrating. (Copy
sources/adprep folder for this)
15.
ESXi update manager
16.
Global Catalog
o
Global catalog (GC) is a role handled by domain controllers in an Active directory
model.
o
The global catalog stores a full copy of all objects in the directory for its host domain
and a partial copy of all objects for all other domains in the forest.
o
„Partial copy‟ refers to the set of attributes that are most used for searching every
object in every domain.
o
All domain controllers can be promoted as a GC.
o
GC helps in faster search of AD objects.
o
The replicas that are replicated to the global catalog also include the access
permissions for each object and attribute.
o
If you are searching for an object that you do not have permission to access, you do
not see the object in the list of search results. Users can find only objects to which
they are allowed access.
o
Global catalog server clients depend on DNS to provide the IP address of global
catalog servers. DNS is required to advertise global catalog servers for domain
controller location.
o
By default, first DC of in a forest will be a global catalog server
17.
Basic networking concepts
18.
RODC
o
New feature in Windows 2008
o
Only have the read only copy of directory database
o
RODC will have all the objects of a normal DC in read only mode. But this doesn‟t
include passwords. RODC does not store password of accounts.
o
Updates are replicated to RODC by writable DC
o
Password caching : A feature which enables RODC to cache password of the logged
in users.
o
DNS can be integrated with RODC but will not directly register client updates. For
any DNS change, the RODC refers the client to DNS server that hosts a primary or
AD integrated zone
19.
NAS vs SAN
o
Both used as storage solution
o
NAS can be used by any device connected using LAN whereas SAN is used only by
server class devices with SCSI
o
NAS is file based whereas SAN is block based storage
o
NAS is cheap while SAN is expensive
o
SAN is comparatively faster than NAS
20.
What is DRS? Types of DRS
o
Distributed Resource Scheduler
o
It is a feature of a cluster
o
DRS continuously monitors utilization across the hosts and moves virtual machines
to balance the computing capacity
o
DRS uses vMotion for its functioning
o
Types of DRS
i.
Fully automated - The VMs are moved across the hosts automatically. No
admin intervention required.
ii.
Partially automated - The VMs are moved across the hosts automatically
during the time of VM bootup. But once up, vCenter will provide DRS
recommendations to admin and has to perform it manually.
iii.
Manual - Admin has to act according to the DRS recommendations
21.
DRS prerequisites
o
Shared storage
o
Processor compatibility of hosts in the DRS cluster
o
vMotion prerequisites
22.
vMotion is not working. What are the possible reasons?
o
Ensure vMotion is enabled on all ESX/ESXi hosts
o
Verify if the ESXi/ESX host can be reconnected or if reconnecting the ESX/ESXi
host resolves the issue
o
Verify that time is synchronized across environment
o
Verify that the required disk space is available
23.
What happens if a host is taken to maintenance mode
o
Hosts are taken to maintenance mode during the course of maintenance
o
In a single ESX/ESXi setup, all the VMs need to be shutdown before getting into
maintenance mode
o
In a vCenter setup If DRS is enabled, the VMs will be migrated to other hosts
automatically.
o
24.
How will you clone a VM in an ESXi without vCenter
o
Using vmkftools
o
Copy the vmdk file and attach to a new VM
o
Using VMware converter
25.
Explain traverse folder
o
Allows or denies moving through a restricted folder to reach files and folders beneath
the restricted folder in the folder hierarchy.
o
Traverse folder takes effect only when the group or user is not granted the "Bypass
traverse checking user" right in the Group Policy snap-in. This permission does not
automatically allow running program files.
1.
Maximum number of LUNs that can be attached to a host (ESXi 5.0)
o256
2.
Maximum number of vCPUs that can be assigned to a VM (ESXi 5.0)
o32
3.
What are the uses of ntdsutil tool?
o
Some of the main uses of ntdsutil tool
i.
Authoritative Restore - Authoritatively restores the Active Directory database
or AD LDS instance
ii.
ifm - Create installation media for writable and RODC setups (Offline DC
provisioning)
iii.
metadata cleanup - Cleans up objects of decommissioned servers
iv.
roles - Transfers and seizes operations master roles
v.
set DSRM password - Resets DSRM administrator password
vi.
snapshot - Manages snapshots of the volumes that contain the Active
Directory database and log files
4.
FSMO roles and its failure scenarios
o
http://www.systemadminguide.in/2013/07/fsmo-roles-in-nutshell.html
5.
IPv6 addresses and its DNS record
o128 bit address
o
Represented as 8 groups of 4 hexadecimel digits seperated by colons
o
Represented by „AAAA‟ record in DNS
oUses DHCP v6 for addressing
6.
Loadbalancer vs Clustering
oClustering
i.
Cluster is a group of resources that are trying to achieve a common objective,
and are aware of one another.
ii.
Clustering usually involves setting up the resources (servers usually) to
exchange details on a particular channel (port) and keep exchanging their
states, so a resource‟s state is replicated at other places as well.
iii.
It usually also includes load balancing, wherein, the request is routed to one
of the resources in the cluster as per the load balancing policy
.
Used to forward requests to either one server or other, but one server does not use the
other server‟s resources. Also, one resource does not share its state with other
resources.
7.
Software installation using group policy
o
This can be done using 2 methods
i.
Assigning
ii.
Publishing
o
Assign :
.
If you assign the program to a user, it is installed when the user logs on to the
computer. When the user first runs the program, the installation is completed.
i.
If you assign the program to a computer, it is installed when the computer
starts, and it is available to all users who log on to the computer. When a user
first runs the program, the installation is completed.
o
Publish :
.
You can publish a program distribution to users.
i.
When the user logs on to the computer, the published program is displayed in
the Add or Remove Programs dialog box, and it can be installed from there.
o
msi packages are used for installation. Normal exe would not work.
o
Windows cannot install the software while the user is already logged on. The user
need to log off and log in
8.
Group policy security filtering for users. Which all users are in there by default.
Members of Authenticated Users group
o
Security filtering is a way of refining which users and computers will receive and
apply the settings in a Group Policy object (GPO)
o
In order for the GPO to apply to a given user or computer, that user or computer must
have both Read and Apply Group Policy (AGP) permissions on the GPO, either
explicitly, or effectively through group membership
o
By default, all GPOs have Read and AGP both Allowed for the Authenticated Users
group.
o
The Authenticated Users group includes both users and computers. This is how all
authenticated users receive the settings of a new GPO when it is applied to an
organizational unit, domain or site
9.
Relevance of host file and its location
oCame before the concept of DNS
o
An FQDN is first checked in Host file
o
Location : C:\Windows\System32\Drivers\etc
10.
L3 switch vs Routers
o
L3 switches just have the ethernet ports only whereas the routers have WAN
interfaces
o
QoS is not available with L3 switches whereas in routers it can be enabled
o
Routers have expansion slots and cards that allow them to use different media types,
like serial connections for T1 and T3 circuits
o
Routers are more intelligent in handling packets
o
L3 switches does not support NAT
11.
VLAN vs Subnet
o
VLAN works at layer 2 while subnet is at layer 3
o
Subnets are more concerned about IP addresses.
o
VLANs bring more network efficiency
o
Subnets have weaker security than VLANs as all the subnet uses the same physical
network
12.
Contents of System state backup
oRegistry
o
COM+ Class Registration database
o
Boot files, including the system files
o
System files that are under Windows File Protection
o
Active Directory directory service (If it is domain controller)
o
SYSVOL directory (If it is domain controller)
o
Cluster service information (If it is a part of a cluster)
o
IIS Metadirectory (If it is an IIS server)
13.
Incremental vs Differential backups
o
Incremental backup - Will take the backup of files whose archive bits are set and
resets it after backup
o
Differential backup - Will take the backup of files whose archive bits are set but does
not reset it after backup
14.
Robocopy
o
Microsoft tool used for copying files effectively
o
It has plenty of options to manage the copy process
15.
How do you patch microsoft applications? Frequency of patches released by Microsoft
oThe Microsoft applications can be patched using WSUS
o
In WSUS, we can create several computer groups to manage this patch process.
o
MS patches are released once in a month
16.
Explain GPO, GPC & GPT
o
GPO - Group Policy Object : Refers to the policy that is configured at the Active
Directory level and is inherited by the domain member computers. You can configure
a GPO at the site level, domain level or OU level. GPO stores policy settings in two
locations GPC and GPT
o
GPO behaviour : Local Policy > Site GPO > Domain GPO > OU GPO > Child OU
GPO
o
GPC - Group Policy Container :This is the AD portion of the group policy. This can
be viewed using ADSI edit. It stores version information, status information, and
other policy information. When you create a new GPO, an AD object of class
groupPolicyContainer gets created under the System\Policies container within your
AD domain
o
GPT - Group Policy Template : The GPT is where the GPO stores the actual settings.
It stores software policy script, and deployment information.
o
GPT is stored in SYSVOL share (\\DomainNameHere\SYSVOL\Policies) whereas
GPC is stored in the AD
17.
What is CPU affinity in VMware? Its impact on DRS?
o
CPU refers to a logical processor on a hyperthreaded system and refers to a core on a
non-hyperthreaded system
o
By setting CPU affinity for each VM, you can restrict the assignment of VMs to a
subset of available processors
o
The main use of setting CPU affinity is when there are display intensive workloads
which requires additional threads with vCPUs.
o
DRS will not work with CPU affinity
http://frankdenneman.nl/2011/01/11/beating-a-dead-horse-using-cpu-affinity/
18.
VMversion 4 vs VMversion 7
oVersion 4
i.
Runs on ESX 3.x
ii.
Max supported RAM 64 GB
iii.
Max vCPUs 4
iv.
MS cluster is not supported
v.
4 NICs/VM
vi.
No USB Support
o
Version 7
.
Runs on vSphere 4.x
i.
Max supported RAM 256 GB
ii.
Max vCPUs 8
iii.
MS cluster is supported
iv.
10 NICs/VM
v.
USB support
19.
What happens to the VMs if a standalone host is taken to maintenance mode?
o
In case of standalone servers , VMware recommends that VMs should be powered off
before putting the server in maintenance mode
o
If we put the standalone host in maintenance mode without powering off the VMs, it
will remain in the „entering maintenance mode‟ state until the VMs are all shutdown
o
When all the VMs are powered down, the host status changes to „under maintenance‟
http://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp#using_drs_clusters_to_manage_resources/c_using_maintenance_mode.html
20.
What is new in Windows server 2012
o
Server core improvements: no need of fresh installation, you can add/remove GUI
from server manager
o
Remotely manage servers , add/remove roles etc using Server manager-manage 2008
and 2008 R2 with WMF 3.0 installation, installed by default in Server 2012
o
Remote server administration tools available for windows 8 to manage Windows
server 2012 infrastructure
o
Powershell v3
o
Hyper-V 3.0
i.
supports upto 64 processors and 1 TB RAM per virtual machine
ii.
upto 320 logical hardware processors and 4 TB RAM per host
iii.
Shared nothing live migration, move around VMs without shared storage
o
ReFS(Resilient file system), upgraded version of NTFS- supports larger file and
directory sizes. Removes the 255 character limitation on long file names and paths,
the limit on the path/filename size is now 32K characters!
o
Improved CHKDSK utility that will fix disk corruptions in the background without
disruption
21.
How does the backup software recognize that a file has changed since last backup?
oThe files use a bit called archive bit for tracking any change in the file.
o
The backup softwares normally checks the archive bit of the file to determine
whether the file has to be backed up or not
22.
How can you edit a vm template?
o
The VM templates cannot be modified as such
o
First , the VM template have to be converted to a virtual machine
o
After making necessary machines in the virtual machine, convert the virtual machine
back to template
23.
VMware configuration maximums
ESXi 5.5 ESXi 5.1 ESXi 5.0 ESXi 4.x
VMs
vCPU 64 64 32 8
RAM 1 TB 1 TB 1 TB 255 GB
vNIC 10 10 10 10
VMDK size 62 TB 1 TB 1 TB 2 TB for 8MB block
Hosts Logical CPU 320 160 160 160 Memory 4 TB 2 TB 2 TB 1 TB LUNs 256 256 256 256 LUN size 64 TB 64 TB 64 TB 64 TB Virtual Machines 512 512 512 320
24.
What is the major difference between Windows server 2008 and windows server 2012 in
terms of AD promotion?
In Win 2012, dcpromo has been depreciated. In order to make a Windows server 2012 to a
domain controller, the ADDS service has to be installed from the server manager. After installation,
run the post-deployment configuration wizard from server manager to promote the server as AD
What is vSAN
?
It is a hypervisor-converged storage solution built by aggregating the local storage attached to the ESXi hosts managed by a vCenter.
Recommended iSCSI configuration?
A separate vSwitch, and a separate network other than VMtraffic network for iSCSI traffic. Dedicated physical NICs should be connected to vSwitch configured for iSCSI traffic.
What is iSCSI port binding ?
Port binding is used in iSCSI when multiple VMkernel ports for iSCSI reside in the same broadcast domain and IP subnet, to allow multiple paths to an iSCSI array that broadcasts a single IP address.
iSCSI port binding considerations ?
Array Target iSCSI ports must reside in the same broadcast domain and IP subnet as the VMkernel port.
All VMkernel ports used for iSCSI connectivity must reside in the same broadcast domain and IP subnet.
All VMkernel ports used for iSCSI connectivity must reside in the same vSwitch. Currently, port binding does not support network routing.
Recommended iSCSI configuration of a 6 NIC infrastructure ? (Answer changes as per
the infrastructure requirements)
2 NICs for VM traffic 2 NICs for iSCSI traffic 1 NIC for vMotion
1 NIC for management network
Post conversion steps in P2V
Adjust the virtual hardware settings as required Remove non present device drivers
Remove all unnecessary devices such as serial ports, USB controllers, floppy drives etc.. Install VMware tools
esxtop --> d --> DAVG
What are standby NICs
These adapters will only become Active if the defined Active adapters have failed.
Path selection policies in ESXi
1. Most Recently Used (MRU) 2. Fixed
3. Round Robin
Which networking features are recommended while using iSCSI traffic
iSCSI port binding Jumbo Frames
Ports used by vCenter
80,443,902
What is 'No Access' role
Users assigned with the 'No Access' role for an object, cannot view or change the object in any way
When is a swap file created
When the guest OS is first installed in the VM
The active directory group, where the members will be ESXi administrators by default.
ESX Admins
Which is the command used in ESXi to manage and retrieve information from virtual
machines ?
vmware-cmd
Which is the command used in ESXi to view live performance data?
esxtop vmkfstools
Port used for vMotion
8000
Log file location of VMware host
\var\log\vmware
Can you map a single physical NIC to multiple virtual switches ?
No
Can you map a single virtual switch to multiple physical NICs?
Yes. This method is called NIC teaming.
VMKernel portgroup can be used for:
vMotion Fault Tolerance Logging Management traffic
Major difference between ESXi 5.1 and ESXi 5.5 free versions
Till ESXi 5.1 free version there was a limit to the maximum physical memory to 32 GB. But from 5.5 onwards this limit has been lifted.
What is IPAM server in Windows server 2012?
IPAM is IP Address Management server in Windows Server 2012. It enables central management of both DHCP and DNS servers. It can also be used to discover, monitor, and audit DHCP and DNS servers.
How to promote a server to domain controller in Windows server 2012?
DCPROMO was the conventional tool used to promote a normal server to DC. This is now deprecated in Server 2012.
In Server 2012, you can convert a server into DC using the server manager console. Under Server Manager, add a new role "Active Directory Domain Services"
REAL TIME SCENARIO
Issue
While performing vMotion, the operation fails at 14% with the below error :
A general system error occurred: Migrtion to host <Destination ESXi IP> failed with erro Connection closed by remote host, possibly due to timeout (0xbad003f).
Migrate virtual machine:A general system error occurred: Migration to host <Destination ESXi IP> failed with error Connection closed by remote host, possibly due to timeout (0xbad003f).
vMotion migration [-1062729272:1406020861428172] (19-71629048648008) failed to receive... Scenarios
Scenario 1: Your management network and vmotion network are in the same subnet using the same physical
NIC.
Consider the case, where the management network and vmotion network are in the same subnet and you have assigned a VLAN id to the vMotion network, the operation fails at 14%.
My first point will be to avoid using same IP subnet for both management and vmotion networks. Because if you use the same subnet, all the vmotion traffic will be forwarded to the physical NIC connected to the management network. This is because, by default all traffic from vmkernel portgroups from the same subnet will be forwarded to the first NIC configured in the ESXi for that IP subnet. Obviously this will be the management network.
And if you still stick to the plan of using same subnet, please make sure that you have not assigned any VLAN id to the vMotion portgroup.
What happens when we assign a VLAN to the vMotion portgroup ? vMotion vmknic will try to communicate with the default gateway and since the default gateway is not tagged with the VLAN id you choose for vMotion, the operation fails.
Scenario 2: Your management network and vmotion network are in the same subnet using different physical
NIC (may be using different vswitches as well).
The comments in the above scenario applies to this scenario also. It doesn't matter if you have created a new vSwitch or a new portgroup or a dedicated physical NIC for the vmotion network, if your management network is in the same subnet, do not assign a VLAN id to the portgroup.
Scenario 3: Your management network and vmotion network in different subnet. In this case you need to check the physical switch configuration.
S
cenarioYou have a single vmdk file of 200 GB and it has two logical volumes C & D with 100 GB each. Suppose you need to add another 100 GB to the D drive making it 200 GB. What would you do ?
The steps are simple and straight forward.
Change the VMDK size using vSphere client to 300 GB (Exisiting 200 GB + required space).
Log in to the VM and ensure that the added disk space is available to the VM as 'Unallocated' space Execute the below commands in command prompt
o diskpart
o list volume
o select volume <volume id>
o extend
Symptom:
Eth0 interface will not be present for a Centos VM after cloning. Only the loopback networking interface will be available. If you try to turn up the interface manually (using the command ifup eth0 or ifup-eth0), you will receive the below error.
Device eth0 does not seem to be present, delaying initialisation
Root Cause:
terms, a new MAC address will be generated for the NIC of the cloned machine. This change happens only in VMware perspective and no modification is made in Centos. Therefore the kernel will be still searching for the NIC with old MAC address and hence fails.
Resolution:
1. Update the exisiting ethernet configuration file to reflect the new MAC address.
Check the new MAC address using vSphere client and modify the ifcfg-eth0 interface configuration using the command:
vi /etc/sysconfig/networking/devices/ifcfg-eth0
Replace HWADDR with the new MAC address 2. Remove the kernel's networking interface rules file
rm -f /etc/udev/rules.d/70-persistent-net.rules
3. Reboot the VM
T
he memory usage of SQL servers is always a hot topic among the system administrators. Any system administrator who handles a SQL server in their environment would have definitely faced this issue. Before going on to the memory monitoring of SQL, we should have answers to the below questions :1. What does SQL do with the memory ?
2. Does it handle memory in the same way as other applications do ?
SQL server uses memory for :
Caching raw data Working on your queries Caching execution plans
The memory management of SQL is different when compared to other applications. SQL is an application with intense I/O operations. Since I/O operations on disk is time consuming, the SQL server uses 'Buffer
Management' mechanism.
'Buffer manager' to access and update database pages 'Buffer cache/pool' to reduce database file I/O
Buffer manager is responsible for handling all read/write operations in the buffer, whereas the normal select, update etc..operations are handled by the database manager.
So when does a system administrator confirms that a memory upgrade is required?
There are performance counters which helps system administrator on this. Will discuss about the main performance counters for analyzing this. (Performance monitors can be accessed by running 'perfmon' in run)
SQLServer:Buffer Manager
Buffer cache hit ratio
Represents the percentage of pages found in the buffer cache without having to read from disk. A higher value for BCHR normally represents a better memory management. When this value dips, we should upgrade the RAM. The value is expected to be 100%.
Page life expectancy
This metric represents the number of seconds a page will stay in the buffer pool without references. In other words, this amount represents cached raw data. Higher the value, better it is. The metric is measured in secs. As a thumb rule, the value should be above 300s.
SQLServer:SQL Statistics
Batch requests/sec
This metric represents the number of batch requests the server is receiving per second. In other words, how busy is my sql server due to incoming requests.
Compilations/sec
This value represents the number of times SQL Server compiles an execution plan per second. We cannot judge the performance with this metrix alone. The performance is deteremined when this metric is compared with Batch requests/sec. As a thumb rule, if the value is less than 10% of the Batch requests/sec, then the performance is desirable. Whereas if the sql server is forced to compile more than 10% of Batches requests/sec then we should understand that there is not enough memory to store the execution plans and we should
consider a memory upgrade.
For example: If your Batch requests/sec is 2000 and if your compilations/sec is less than 200 , then the value is desirable.
SQLServer:Memory Manager
Memory grants pending
than 0 represents a memory issue. Target Server Memory
This metric represents the ideal amount of memory the server can consume. This value is almost equal to the RAM (if no limit is set using the SQL management studio).
Total server memory
This metric represents the amount of memory the server has committed using the memory manager. This counter shows what is actually used and the value will be low upon starting, and will increase gradually as the SQL server brings pages to its buffer pool and finally reaches a steady state. When this reaches steady state, this will be almost equivalent to the Target Server Memory. Once it reaches the steady state, the value is not expected to dip. If this dips, it represents the memory deallocation due to memory requirement from OS or other applications. If this value is higher than target, then your server could benefit from additional RAM. All these counters are just direction pointers. Please don't rely on one counter alone to confirm the requirement of memory upgrade.
Issue
You will find software iscsi adapter missing in ESXi
Resolution
1. Log in to the vSphere Client 2. Select the configuration tab 3. Select Storage Adapters 4. Click on the Add option
5. You will be given the option to add Software iSCSI adapter Steps for cloning VM using SSH:
SSH to the ESXi host
Identify the path of the source (say, /vmfs/volumes/datastore1/SourceVM/where sourceVM is the name of the source VM)
Create a new folder in the desired datastore
mkdir /vmfs/volumes/datastore1/DesintationVM
Clone the sourceVM vmdk to the newly created folder DestinationVM
vmkfstools -i /vmfs/volumes/datastore1/SourceVM/sourceVM.vmdk /vmfs/volumes/datastore1/DesintationVM/DesintationVM.vmdk
Once cloning is completed, proceed with the creation of the new VM using vSphere client In the option where you need to provision the harddisk for the new VM, choose 'Use an existing
virtual disk'
Browse and point the newly cloned vmdk file
below error:
“Failed to start the virtual machine.
Module DevicePowerOn power on failed. Unable to create virtual SCSI device for scsi…”
Cause
You might have tried to PowerOn a VM with ESXi incompatible vmdk file. This VMDK file will be compatible only with VMware workstation, VMware servers etc and not with the ESXi.
Resolution
Steps:
- Remove the vmdk file from the VM. (Only from the VM!!!) - Connect to the ESXi box using putty
- Execute the below command to convert the existing vmdk file to new ESXi compatible vmdk
vmkfstools -i existing_vmdk_location new_vmdk_location
- Point the VM with the newly formatted vmdk file and Power On. That‟s it….
Symptoms
VMs will be shown as inaccessible in the vCenter
Reason
A VM can become inaccessible due to any of the below reason:
Issue with the ESXi servers Issue with the vCenter Issue with the datastore
Resolution
In all the three cases these are the below three troubleshooting steps:
Login to the ESXi using SSH
Run any of the below commands to restart the management agents
/etc/init.d/hostd restart /etc/init.d/vpxa restart or
services.sh restart
If this step did not resolve the issue for you, try the second step
Second step will be to remove the VM from the inventory and add using the vmx file
Right click on the affected VM
Choose the option 'Remove from the Inventory' (Be cautious about this action...Do not delete the VM)
After this step, go to the vmx location of the VM Right click on the VM and 'Add to the Inventory'
This step will definitely resolve your issue. But this step works fine only when we know the vmx location of the VM. If you are not sure about the vmx location you will end up in adding incorrect VMs.
Keep in your mind that you cannot access the vmdk location to find the vmx path when the VM is inaccessible.
In these kind of situations, the best method is to use command line, the third step!!!
Login to the ESXi hosting the inaccessible VM using SSH
vim-cmd vmsvc/getallvms
You will receive a message "Skipping invalid VM '144' " along with the details of valid VMs. The skipped VM will be the invalid one. The value '144' represents the vmid of the VM.
Now run the below command to reload the invalid VM
vim-cmd vmsvc/reload vmid where vmid is the id of the invalid VM
That will save your day!!!
Scenario
When we try to reduce or shrink the size of an existing vmdk file, the operation fails.
Resolution
There is no option to reduce the size using vSphere client. For this you may need to use putty or cli. Please remember to delete unwanted data from the OS and to shrink the partition internally using the diskmgmt.msc tool. After shrinking , perform the below:
Login to the ESXi using putty
Browse to the vmdk location (eg: cd vmfs/volumes/datastore1/VMname)
Take a backup of the existing vmname.vmdk and vmname-flat.vmdk files using thecp command in linux (cp filename backup_filename)
Open the vmdk file using vi editor
o vi vmname.vmdk
Modify the value corresponding to RW to the required disk space. If you need to shrink the file to xGB, use the value : x*1024*1024*2. For eg: if you want to shrink the disk to 25GB, give the value 25*1024*1024*2= 52428800
Once finished save the file and use vmkfstools command to clone a disk using the new settings.
o vmkfstools -i vmname.vmdk vmname-new.vmdk
Remove the old vmdk files
o rm vmname.vmdk rm vmname-flat.vmdk
Once removed, again use the vmkfstools to clone vmdk files of the same old name.
o vmkfstools -i vmname-new.vmdk vmname.vmdk
Using vi client , remove the hard disk from virtual machine and add again.
Scenario
When we use thin provisioned vmdk, the size of the vmdk expands as we pile up data in the OS. But if we delete some data from OS, the reclaimed space in the OS will not be reclaimed from the vmdk. It will continue to occupy the maximum space it have ever used after creation.
Resolution
There is no resolution to reduce the size using vSphere client. For this you may need to seek the help of putty or cli.
- Login to the ESXi using putty
- Browse to the vmdk location (eg: cd vmfs/volumes/datastore1/VMname - List the available vmdk files in this location using the command:
ls –lh *.vmdk
- To know the actual size occupied by the vmdk file <
du –h *.vmdk
- To shrink the size of the vmdk file
vmkfstools -K AD01.vmdk
- Re check the actual size of vmdk now. You will feel the difference !!!
Resizing an IDE virtual disk
1. Remove the IDE vmdk from the VM2. Edit the “vmdk” file (can be found under cd /vmfs/volumes/<datastore_name>/<vm_name>/) 3. Change ddb.adapterType from “ide” to “lsilogic”
4. Add the IDE vmdk to the VM 5. Change the size of the disk
6. Remove the IDE vmdk from the VM 7. Edit the “vmdk” file
8. Change ddb.adapterType from “lsilogic” to “ide” 9. Add the IDE vmdk to the VM
How to remove Dead or Error iscsi targets from ESXi |
VMware
Issue:-
Sometime we may find an iscsi target associated to an iscsi adapter being greyed out and marked as Dead or Error. In VMkernel log you may receive an error as given below:
WARNING: NMP: nmpDeviceAttemptFailover:658:Retry world failover device
"naa.6090a05850f3465b871325e61b6af905" - failed to issue command due to Not found (APD), try again... This is a result of an improper deletion of a LUN/iscsi target from the storage adapter.
Resolution:-
Enter the host into maintenance mode (Just to be safe)
esxcfg-rescan -d vmhba3
Replace vmhba id with the id of your vmhba adpater.
Ensure that you are not receiving any errors by checking vmkernel log file
tail -f /var/log/vmkernel.log
Exit from maintenance mode
You may be required to refresh the storage adapters after the rescan.
VM disk cannot be resized- Failed to extend the disk
Issue:-
-With the vSphere Client, if you edit a VM's settings and then select one of its virtual disks, the option to resize the disk is greyed out.
-When trying to extend the disk using vmkftools for resizing, you will receive the below error: Failed to extend the disk. Failed to lock the file.
-When you extend the disk using vsphere client, the change is not getting reflected.
Root cause:-
The VM will be having a snapshot. Because when a snaphot is taken the actual VMDK file will be locked and the changes will be written to a new delta file. Due to this reason, the actual VMDK file could not be resized. Another possible reason: If the disk is IDE, the change may not get reflected. The resolution step for this issue is mentioned here
Resolution:-
Remove the snapshot file and then try to resize.
Cannot create VMs with virtual machine version 9 in
VMware ESXi
O
ne of the main addtion of VMware ESXi 5.1 is the introduction of new VM version (VM version 9).But when we try to create a new virtual machine using vsphere client 5.1, the option to choose VM version 9 will not be available. This is an intentional omission from VMware. To promote the use of vSphere web client. The new option of VM version 9 is available only in vSphere web client
Issue taking backup of ESXi Configuration
Issue:-
You might have faced the following issue when trying to take a configuration backup of ESXi
C:\Program Files\VMware\VMware vSphere CLI>vicfg-cfgbackup.pl -save --server 172.xx.xx.xxx backup.bak Enter username: root
Enter password:*****
Server version unavailable at 'https://localhost:443/sdk/vimService.wsdl' at C:/Program
Files/VMware/VMware vSphere CLI/Perl/lib/VMware/VICommon.pm line 545, <STDIN> line 2.
Resolution:-
Run the perl.exe and vicfg-cfgbackup.pl from the original location
C:\>"C:\Program Files\VMware\VMware vSphere CLI\Perl\bin\perl.exe" "C:\Program
Files\VMware\VMware vSphere CLI\bin\esxcfg-cfgbackup.pl" -save --server 172.xx.xx.xx test_bkf.bkf Enter username: root
Enter password:*******
Saving firmware configuration to test_bkf.bkf ...
By default the backup of configuration file will be saved under
C:\Users\username\AppData\Local\VirtualStore\Program Files\VMware\VMware vSphere CLI
Symptom:
The host and VMs in a vcenter server appears to be disconnected.
Issue:
The host and its corresponding vms could appear as disconnected due to issue with any of the following services.
vpxa - a service which runs in the esxi host. This service communicates with vcenter server. hostd - core service which runs in the esxi host
vpxd - a service which runs in the vcenter server which communicates with the vpxa
Resolution:
1. Try to ping the ESXi host. This ensures that the host is reachable
2. Ensure you can login to the VMs remotely. This ensures that VMs in the host are working fine. 3. Try to login to the ESXi host using vsphere client. This ensures that the hostd services are running
perfectly. If this step fails, restart the hostd service using putty.
4. If the above three steps worked fine for you, the issue would be with the vpxa or vpxd service. In that case, first try to restart the vpxa service in the host and if that didnot resolve the issue, try restarting vcenter server service of the vcenter.
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1. What is a Hypervisor?
It is a program that allows multiple operating systems to share a single hardware host. Each operating system appears to have the host’s processor, memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual machines) cannot disrupt each other.
2. What is the hardware version used in VMware ESXi 5.5?
Version 10
Below is the table showing the different version of hardware used in different VMware products along with their release version
Virtual Hardware Version Products
10 ESXi 5.5, Fusion 6.x, Workstation 10.x, Player 6.x 9 ESXi 5.1, Fusion 5.x, Workstation 9.x, Player 5.x 8 ESXi 5.0, Fusion 4.x, Workstation 8.x, Player 4.x 7 ESXi/ESX 4.x, Fusion 2.x/3.x Workstation 6.5.x/7.x,Player 3.x
6 Workstation 6.0.x
4 ACE 2.x, ESX 3.x, Fusion 1.x, Player 2.x
3 and 4 ACE 1.x, Player 1.x, Server 1.x, Workstation 5.x, Workstation 4.x
3 ESX 2.x, GSX Server 3.x
3. What is the difference between the vSphere ESX and ESXi architectures?
VMware ESX and ESXi are both bare metal hypervisor architectures that install directly on the server hardware.
Although neither hypervisor architectures relies on an OS for resource management, the vSphere ESX architecture relied on a Linux operating system, called the Console OS (COS) or service console, to perform two management functions: executing scripts and installing third-party agents for hardware monitoring, backup or systems management.
In the vSphere ESXi architecture, the service console has been removed. The smaller code base of vSphere ESXi represents a smaller “attack surface” and less code to patch, improving reliability and security.
4. What is a .vmdk file?
This isn’t the file containing the raw data. Instead it is the disk descriptor file which describes the size and geometry of the virtual disk file. This file is in text format and contains the name of the –flat.vmdk file for which it is associated with and also the hard drive adapter type, drive sectors, heads and cylinders, etc. One of these files will exist for each virtual hard drive that is assigned to your virtual machine. You can tell which –flat.vmdk file it is associated with by opening the file and looking at the Extent Description field. Follow the below link for more details
VMware files description
5. What are the different types of virtualization?
Server Virtualization – consolidating multiple physical servers into virtual servers that run on a single physical server.
Application Virtualization – an application runs on another host from where it is installed in a variety of ways. It could be done by application streaming, desktop virtualization or VDI, or a VM package (like VMware ACE creates with a player). Microsoft Softgrid is an example of Application virtualization. Presentation Virtualization – This is what Citrix Met frame (and the ICA protocol) as well as Microsoft Terminal Services (and RDP) are able to create. With presentation virtualization, an application actually runs on another host and all that you see on the client is the screen from where it is run.
Network Virtualization – with network virtualization, the network is “carved up” and can be used for multiple purposes such as running a protocol analyzer inside an Ethernet switch. Components of a virtual network could include NICs, switches, VLANs, network storage devices, virtual network containers, and network media.
Storage Virtualization – with storage virtualization, the disk/data storage for your data is consolidated to and managed by a virtual storage system. The servers connected to the storage system aren’t aware of
where the data really is. Storage virtualization is sometimes described as “abstracting the logical storage from the physical storage.
6. What is VMware vMotion and what are its requirements?
VMware VMotion enables the live migration of running virtual machines from one physical server to another with zero downtime.
VMotion lets you:
Automatically optimize and allocate entire pools of resources for maximum hardware utilization and
availability.
Perform hardware maintenance without any scheduled downtime.
Proactively migrate virtual machines away from failing or under performing servers. Below are the pre-requisites for configuring vMotion
Each host must be correctly licensed for vMotion
Each host must meet shared storage requirements
vMotion migrates the vm from one host to another which is only possible with both the host are sharing a common storage or to any storage accessible by both the source and target hosts. A shared storage can be on a Fibre Channel storage area network (SAN), or can be implemented
using iSCSI SAN and NAS.
If you use vMotion to migrate virtual machines with raw device mapping (RDM) files, make sure to maintain consistent LUN IDs for RDMs across all participating hosts.
Each host must meet the networking requirements
Configure a VMkernel port on each host. Dedicate at least one GigE adapter for vMotion.
Use at least one 10 GigE adapter if you migrate workloads that have many memory operations. Use jumbo frames for best vMotion performance.
Ensure that jumbo frames are enabled on all network devices that are on the vMotion path including physical NICs, physical switches and virtual switches.
7. What is the difference between clone and template in VMware?
Clone
You cannot convert back the cloned Virtual Machine.
A Clone of a Virtual Machine can be created when the Virtual Machine is powered on Cloning can be done in two ways namely Full Clone and Linked Clone.
A full clone is an independent copy of a virtual machine that shares nothing with the parent virtual machine after the cloning operation. Ongoing operation of a full clone is entirely separate from the parent virtual machine.
A linked clone is a copy of a virtual machine that shares virtual disks with the parent virtual machine in an ongoing manner. This conserves disk space, and allows multiple virtual machines to use the same software installation.
Cloning a virtual machine can save time if you are deploying many similar virtual machines. You can create, configure, and install software on a single virtual machine, and then clone it multiple times, rather than creating and configuring each virtual machine individually.
Template
A template is a master copy or a baseline image of a virtual machine that can be used to create many clones.
Templates cannot be powered on or edited, and are more difficult to alter than ordinary virtual machine.
You can convert the template back to Virtual Machine to update the base template with the latest released patches and updates and to install or upgrade any software and again convert back to template to be used for future deployment of Virtual Machines with the latest patches.
Convert virtual Machine to template cannot be performed, when Virtual machine is powered on. Only Clone to Template can be performed when the Virtual Machine is powered on.
A template offers a more secure way of preserving a virtual machine configuration that you want to deploy many times.
When you clone a virtual machine or deploy a virtual machine from a template, the resulting cloned virtual machine is independent of the original virtual machine or template.
8. What is promiscuous mode in Vmware?
Promiscuous mode is a security policy which can be defined at the virtual switch or portgroup level
A virtual machine, Service Console or VMkernel network interface in a portgroup which allows use of promiscuous mode can see all network traffic traversing the virtual switch.
If this mode is set to reject, the packets are sent to intended port so that the intended virtual machine will only be able to see the communication.
Example: In case you are using a virtual xp inside any Windows VM. If promiscuous mode is set
to reject then the virtual xp won’t be able to connect the network unless promiscuous mode is enabled for the Windows VM.
9. What is the difference between Thick provision Lazy Zeroed, Thick provision Eager Zeroed and Thin provision?
Thick Provision Lazy Zeroed
Creates a virtual disk in a default thick format.
Space required for the virtual disk is allocated when the virtual disk is created.
Data remaining on the physical device is not erased during creation, but is zeroed out on demand at a later time on first write from the virtual machine.
Using the default flat virtual disk format does not zero out or eliminate the possibility of recovering deleted files or restoring old data that might be present on this allocated space.
You cannot convert a flat disk to a thin disk. Thick Provision Eager Zeroed
A type of thick virtual disk that supports clustering features such as Fault Tolerance. Space required for the virtual disk is allocated at creation time.
In contrast to the flat format, the data remaining on the physical device is zeroed out when the virtual disk is created.
It might take much longer to create disks in this format than to create other types of disks. Thin Provision
It provides on on-demand allocation of blocks of data.
All the space allocated at the time of creation of virtual disk is not utilized on the hard disk, rather only the size with utilized data is locked and the size increases as the amount of data is increased on the disk.
With thin provisioning, storage capacity utilization efficiency can be automatically driven up towards 100% with very little administrative overhead.
10. What is a snapshot?
A snapshot is a “point in time image” of a virtual guest operating system (VM). That snapshot contains an image of the VMs disk, RAM, and devices at the time the snapshot was taken. With the snapshot, you can return the VM to that point in time, whenever you choose. You can take snapshots of your VMs, no
matter what guest OS you have and the snapshot functionality can be used for features like performing image level backups of the VMs without ever shutting them down.
11. What is VDI?
VDI stands for 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”.
Once VDI is used the end user connect to their desktop using a device called thin client. The end user can also connect to their desktop using VMware Horizon View installed on any
desktop or mobile devices
12. What is VMware HA?
VMware HA i.e. High Availability which works on the host level and is configured on the Cluster. A Cluster configured with HA will migrate and restart all the vms running under any of the host in
case of any host-level failure automatically to another host under the same cluster. VMware HA continuously monitors all ESX Server hosts in a cluster and detects failures. VMware HA agent placed on each host maintains a heartbeat with the other hosts in the cluster
using the service console network. Each server sends heartbeats to the others servers in the cluster at five-second intervals. If any servers lose heartbeat over three consecutive heartbeat intervals, VMware HA initiates the failover action of restarting all affected virtual machines on other hosts.
You can set virtual machine restart priority in case of any host failure depending upon the critical nature of the vm.
NOTE: Using HA in case of any host failure with RESTART the vms on different host so the vms state will be interrupted and it is not a live migration
13. What is the difference between VMware HA and vMotion?
VMware HA is used in the event when any of the hosts inside a cluster fails then all the virtual machines running under it are restarted on different host in the same cluster.
Now HA is completely dependent on vMotion to migrate the vms to different host so vMotion is just used for the migration purpose between multiple hosts. vMotion also has the capability to migrate any vm without interrupting its state to any of the host inside cluster.