What is Virtualization?
Virtualization is an architecture that allows you to run multiple OS simultaneously on a single computer
Explain FT?
It creates a secondary copy of the virtual machine on a different host and keeping the two VMs in sync. The secondary VM can immediately take over in the event of an ESXi host failure. FT provides zero downtime and zero data loss, it is usually used for business-critical applications that must be available all the time. It supports up to 8 vCPU's and 64GB Memory. vLockstep technology is used by VMware FT.
What’s VMFS?
VMFS is block level
high-performance clustered filing system. It is often shared
between multiple ESXi hosts or VMs.
What’s the difference between VMFS and NFS?
NFS is file level system. VMFS is block level file system.
What is VMKernel, and why is it important?
VMkernel is a
virtualization interface between a Virtual Machine and the ESXi host, which
stores VMs. It is responsible for allocating all available resources of the
ESXi host to VMs such as memory, CPU, storage, etc. It’s also controlled
special services such as vMotion, Fault tolerance, NFS, traffic management, and
iSCSI. To access these services, the VMkernel port can be configured on the
ESXi server using a standard or distributed vSwitch. Without VMkernel, hosted
VMs cannot communicate with the ESXi server.
What are the hypervisor and their types?
A hypervisor is a
virtualization layer that enables multiple operating systems to share a single
hardware host. Each operating system or VM is allocated physical resources such
as memory, CPU, storage, etc. Hyper-V which is installed directly onto the
hardware and controls all physical resources.
Will the FT work if the vCenter Server goes down?
vCenter Server is only required to enable
Fault Tolerance on a VM. Once it is configured, vCenter is not required to be
online for FT to work. FT will failover between primary and secondary occurs even if the vCenter is down.
What is
the main difference between VMware HA and FT?
HA is enabled per cluster, and VMware FT is
enabled per VM. In HA, VMs will be re-started and powered-on on another host in
case of a host failure, while in FT, there is no downtime because the second
copy will be activated in case of host failure.
What is
virtual networking?
A network of VMs running on a physical server
that is connected logically with each other is called virtual networking.
What is
vSS?
vSS stands for Virtual Standard Switch is
responsible for the communication of VMs hosted on a single physical host. it
works like a physical switch that automatically detects a VM which wants to
communicate with another VM on the same physical server.
What is vDS?
vDS stands for Virtual Distributed Switch acts
as a single switch in a whole virtual environment and is responsible for
providing central provisioning, administration, and monitoring of the virtual
network.
How many maximum standard ports per host are available?
4096 ports per host are available either in a
standard switch or distributed switch.
What are the main benefits of a distributed switch (vDS)?
vDS can provide:
- The
central administration for a virtual data center
- Central
provision, and
- Monitoring
What is the VMKernal adapter, and why is it used?
VMKernel adapter provides network connectivity
to the ESXi host to handle network traffic for vMotion, IP Storage, NAS, Fault
Tolerance, and vSAN. For each type of traffic, such as vMotion, vSAN, etc.
separate VMKernal adapter should be created and configured.
What is the main use of port groups in data center
virtualization?
You can segregate the network traffic using
port groups such as vMotion, FT, management traffic, etc.
What are the three-port groups configured in ESXi networking?
- Virtual
Machine Port Group – Used for Virtual Machine Network
- Service
Console Port Group – Used for Service Console Communications
- VMKernel
Port Group – Used for VMotion, iSCSI, NFS Communications
What is
VLAN, and why use it in virtual networking?
A logical configuration on the switch port to
segment the IP Traffic where each segment cannot communicate with other
segments without proper rules is called VLAN. Every VLAN has a proper number
called VLAN ID.
What is VLAN Tagging?
The practice of inserting VLAN ID into a
packet header to identify which VLAN packet belongs to is called VLAN tagging.
What are the three network security policies/modes on vSwitch?
- Promiscuous
mode
- MAC
address change
- Forged
transmits
What is the promiscuous mode on vSwitch?
Promiscuous mode is a security policy that can
be defined at the virtual switch or portgroup level in vSphere ESX/ESXi. A
virtual machine, Service Console, or VMkernel network interface in a portgroup
that allows the use of promiscuous mode can see all network traffic traversing
the virtual switch.
By default, a guest operating system’s virtual
network adapter only receives frames that are meant for it. Placing the guest’s
network adapter in promiscuous mode causes it to receive all frames passed on
the virtual switch that is allowed under the VLAN policy for the associated
portgroup. This can be useful for intrusion detection monitoring or if a
sniffer needs to analyze all traffic on the network segment.
What are PSC and its components?
PSC stands for Platform Services Controller,
first introduced in version 6 of VMware vSphere, which handles infrastructure
security functions. It has three main components.
- Single
Sign-On (SSO)
- VMware
Certificate Authority (CA)
- Licensing
service
What is a datastore?
A datastore is a storage location where
virtual machine files are stored and accessed. Datastore is based on a file
system which is called VMFS, NFS.
Explain disk types are in VMware?
There are three disk types in vSphere.
- Thick Provisioned
Lazy Zeroes:
every virtual disk is created by default in this disk format. Physical
space is allocated to a VM when a virtual disk is created. It can’t be
converted to a thin disk.
- Thick Provision
Eager Zeroes:
this disk type is used in VMware Fault Tolerance. All required disk space
is allocated to a VM at the time of creation. It takes more time to create
a virtual disk compare to other disk formats.
- Thin provision: It provides an
on-demand allocation of disk space to a VM. When data size grows, the size
of a disk will grow. Storage capacity utilization can be up to 100% with
thin provisioning.
What is Storage vMotion?
It is similar to traditional vMotion; in
Storage vMotion, a virtual disk of a VM is moved from one datastore to another.
During Storage vMotion, virtual disk types think provisioning disk can be
transformed to thin-provisioned disk.
How many maximum hosts can manage a vCenter Server in vSphere
6.0?
In vSphere 6.0, a single vCenter Server can
manage up to 1000 hosts either in Windows or vCenter Appliance (vCSA). In
vSphere 6.5 and 6.7, 2000 hosts, and in vSphere 7.0, 2500 can be managed by a
single vCenter Server.
How many hosts can be managed by a cluster in vSphere 6.0?
A single cluster can manage a maximum of 64
hosts in VMware vSphere 6.0 and onward versions.
How can maximum VMs be managed by a single cluster?
A single cluster can manage a maximum of 8000
VMs.
How many licensing options are for vSphere 6.0?
There are three licensing options for vSphere
6.0:
- Standard Edition: Contains 1
vCenter Server Standard license, up to 2 vCPUs for Fault Tolerance,
vMotion, Storage vMotion, HA, VVols, etc.
- Enterprise
Edition:
Same as Standard Edition additionally APIs for Array Integration and
Multipathing, DRS, and DPM.
- Enterprise Plus: Includes all
Standard and Enterprise Editions features with additional Fault Tolerance
up to 4 vCPUs and 64GB of RAM. It also includes Distributed vSwitch and
the most expensive licensing option of vSphere 6.0.
How
much Maximum RAM can support vSphere 6.0?
It supports up to 12TB of RAM per host in
vSphere 6.0 and vSphere 6.5 and 16TB of RAM per host in VMware vSphere 6.7 and
7.0.
What is
the Content Library?
Content Library is the central location point
between two different geographical locations with vCenter Servers where you can
store VM templates, ISO images, scripts, etc. and share them between
geographical locations
What are the main benefits of content libraries?
We create VM templates and share on another
geographical location without creating again on other locations. It has many
benefits, such as sharing and consistency, storage efficiency, and secure
subscription.
What is VMFS?
VMFS is a file system for a VM in VMware
vSphere. VMFS is a datastore that is responsible for storing virtual machine
files. VMFS can also store large files, which size can be up to 64TB in vSphere
6.0. In the latest versions of VMware vSphere, VMFS 6 is used to store VMs.
What is vSAN?
Virtual SAN is software-defined storage first
introduced in vSphere 5.5 and is fully integrated with vSphere. It aggregates
locally attached storage of ESXi hosts, which are part of a cluster, and
creates a distributed shared solution.
What is cold migration?
To move a powered-off VM from one host to
another is called cold migration.
What is Storage vMotion?
To move a powered-on VM from one datastore to
another is called Storage vMotion.
Are
there VSAN ready nodes are available in the market?
Yes, vSAN-ready, such as VxRail 4.0 and 4.5,
are available in the market. VxRail is the combination of min 3 servers that
are part of a cluster and can scale up to 64 servers.
How minimum servers/hosts are required to configure vSAN?
To configure a vSAN, you should have a minimum
of 3 ESXi hosts/servers in the form of a vSAN cluster. If one of the servers
fails, a vSAN cluster will fail.
How are many maximum ESXi hosts allowed for vSAN?
64 hosts are max allowed to configure a vSAN
cluster.
How many types of storage can we use in our virtual environment?
- Direct
Attached Storage
- Fiber
Channel (FC)
- iSCSI
- Network
Attached Storage (NAS)
What is NFS?
Network File System (NFS) is a file-sharing
protocol that ESXi hosts use to communicate with a NAS device. NAS is a
specialized storage device that connects to a network and can provide file
access services to ESXi hosts.
What is Raw Device Mapping (RDM)?
Raw Device Mapping (RDM) is a file stored in a
VMFS volume that acts as a proxy for a raw physical device. RDM enables you to
store virtual machine data directly on a LUN. RDM is recommended when a VM must
interact with a real disk on the SAN.
What is iSCSI storage?
An iSCSI SAN consists of an iSCSI storage
system, which contains one or more storage processors. TCP/IP protocol is used
to communicate between host and storage array. An iSCSI initiator is configured
with the ESXi host. an iSCSI initiator can be hardware-based, either dependent
or independent, and software-based is known as an iSCSI software initiator.
What is VMware DRS?
DRS stands for Distributed Resource Scheduler,
which automatically balances available resources among various hosts by using
clusters or resource pools. With the help of HA, DRS can move VMs from one host
to another to balance the available resources among VMs.
Manual: vCenter will suggest migration recommendations for VM's
Partially Automated: VM's will be automatically placed onto hosts at power on and vCenter will suggest migration recommendations
Fully Automated: VM's will be automatically placed onto hosts at power on and will be automatically migrated to attain best use of resources.
What monitoring method is used in vSphere HA?
- Network
Heartbeat
- Datastore
Heartbeat
How is the master host elected in vSphere HA?
When HA is enabled in a cluster, all hosts
take part in a selection process to be selected as a master host. A host which
has the highest number of datastores mounted will be selected as a master host.
All other hosts will remain slave hosts.
What is the purpose of VMware Tools?
It is a suite of utilities that are used to
enhance the performance of a VM in the form of graphics, mouse/keyboard
movement, network card, and other peripheral devices.
What is VMware DPM?
Stands for Distributed Power Management is a
feature of VMware DRS that is used to monitor required resources in a cluster.
When the resources are decreases due to low usage, VMware DPM consolidates
workloads and shut down the hosts which are not being used, and when resources
are increased it automatically power on the un-used hosts.
What is VMware vCenter Enhanced Linked Mode and How It Works?
VMware vCenter Server Enhanced Linked Mode
(ELM) is one of the vSphere advanced features that allows connecting multiple
vCenter Servers to provide a single interface where you can view, search, and
manage permissions, replications of roles, policies, and licenses between
multiple vCenter Servers.
It allows you to simplify enterprise virtual
environments deployed in the same or multiple sites with multiple vCenter
Server while deploying vCenter Server as VCSA or Windows Servers.
What is
the use of Promiscuous Mode?
Promiscuous mode is
useful when you want to run a virtual machine with network sniffers helps you
to capture packet of that network. Moreover, if the promiscuous mode set to
accept, all the communication is visible to all the virtual machines. The
default mode is Reject. If Accept is selected, VM will receive all traffic port
group via vSwitch.
What is
Cold and Hot Migration?
When you migrate powered
off or suspended, it is known as cold migration. When you migrate your running
power on virtual machines, it is known as hot migration.
What is
VMware HA Admission Control Policy?
The Admission Control
feature in vSphere HA ensures that sufficent resources are available in a HA
cluster to provide failover protection. You can use Admission Control to
determine whether a user will be allowed to power on more VMs than the HA
cluster has the capacity to support.
Admission Control ensures
that resources will always be available on the remaining hosts in the HA
cluster to power on the virtual machines that were running on a failed host. If
you enable this feature, the VM power-on operations that violate availability
constraints will be disallowed.
What is
virtual memory ballooning?
Virtual memory ballooning
is a computer memory reclamation technique used by a hypervisor to allow the
physical host system to retrieve unused memory from certain guest virtual
machines (VMs) and share it with others. Memory ballooning allows the total amount
of RAM required by guest VMs to exceed the amount of physical RAM available on
the host. When the host system runs low on physical RAM resources, memory
ballooning allocates it selectively to VMs.
When the ESXi host memory
state is High, None of the action will be taken by hypervisor expect
Transparent page sharing.
How many disk types are in VMware?
Thick
Provisioned Lazy Zeroes
Thick provision means all
the space designated for the virtual disk files is reserved when the VM is
created. Lazy zero means that blocks containing older data on the storage
device are only cleared when the virtual machine writes new data to the disk
for the first time.
Thick
Provision Eager Zeroes
The description “thick
provision” simply means that all the space that is required for the virtual
disk files is reserved when the VM is created. Eager Zeroes means that blocks
on the physical storage device are formatted with zeros to overwrite any older
data.
Thin
Provisioning
Thin Provisioning is
VMware vSphere Technology allows Virtual Disk storage allocation on demand. In
other words, allocate storage space only when VM needs it.
In thin provisioning, all
of the VM’s configured storage doesn’t get allocated to VM during creation.
Instead, space allocation happens as when VM virtual disk starts growing.
What is
the difference between clone, snapshot and template?
A clone is
a copy of an existing virtual machine. The existing virtual machine is called
the parent of the clone. When the cloning operation is complete, the clone is a
separate virtual machine.
The VMware snapshot preserves
the state and data of the VM at the current point in time, so when you are done
testing, you can quickly revert the VM back to a desired state.
A template is
a master copy of a virtual machine that can be used to create many clones.
What is vMotion?
Move running virtual
machines from one physical server to another with no impact to end users
What is
SVmotion?
Storage VMotion relocates
virtual machine disk files from one shared storage location to another shared
storage location with zero downtime.
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
How
does HA know to restart a VM from a dropped Host?
Storage lock will be
removed from the metadata
Explain P2V steps?
1. Right-click on the ESX
host and click import machine
2. Select the source machine as physical computer and click Next, provide physical computer hostname and administrative credentials.
3. vConverter will
connect to the physical machine and Agent will be on that system.
4. Review the disk
volumes
5. choose the Disk volume
and ignore the page and hibernation files.
6. You can see the
destination ESX host.
7. Provide name to the
VM.
8. Select the datastore
and NIC’s you want to connected to the new vm.
9. Install vmware tools.
10. You will be given the
option to schedule the P2V conversion
11. After you click Finish, the P2V conversion (import) will begin
How do you manage server profiles?
How do you configure a Chassis or Rackmount?
How do you troubleshoot link down issue?
First we have to check the Excel cutsheet of the server means which port is connected to which NIC.
First ping all the vms are in working condition or not.
If it is ok then ask the DCI team to check whether the n/w cable has any cuts or SFP is properly working or not or is there any brakes to the pin.
If there is any issues with above cases then exchange the parts otherwise we will check whether it is a hardware issue means adopter is properly working or not.
It is issues with this then replace the adopter and check it is working or not.
If it is ok, then issue solved otherwise we will raise a case with network team.
How do you troubleshoot VMs are losing networks?
or
How do you troubleshoot VM’s are not responding in a specific cluster?
1. I will check any recent changes performed on those VMS.
2. I will check any glitches or network errors on VOBD logs, from the logs I can see, it can be a hardware issue or VM level issue.
3. If it is a hardware issue I will go with vendor case and try to replace the NICHE Adopters or SFP Modules.
4. If it is a VM level issue, I will check from PORT level, Is there any issue with it like any recent IP Changes or configuration changes.
5. Later I tried to migrate one VM to the next host and check the status of VM network, still it is not resolved I will engage with network team and ask them to check from network level, still network team also not resolved the issue, I will raise the VM ware case to check any bugs cause the issue.
Login to the VC
navigate to the network then select DVswitch to where you have to create a Vlan
just right click on that and select distributed portgroup and create vlan by
giving vlan id
Disaster servers are
the backup of production servers. In case any production disaster cause, the
application availability is unavailable in that situation the Disaster server
will act like production. That means App Teams failover their applications from
production to DR. In that way App teams keep their application high availability.
In my environment we use to patch the ESXi on every 6 months. VMware provide any security patch it will update as per the criticality.
Give me an example where you have solved a significant problem?
What is replication and deduplication?
Replication means maintain same copy of data somewhere and deduplication means delete the duplicate files.
What files do you use for bid manager?
By using update manager or POWERCLI scripts we can install VMware tools
on 100 vms simultaneously
Login to VC goto update manager i will create a baseline, attach the
baseline and remediate
8000
what is NIC teaming policy?
Two NICs to be tie up with one network.
what are the management services in ESXi?
Hostd, vpxa
POWERCLI and Update manager
Scripted upgrade.
Use the ESX command line interface (CLI).
vSphere Auto Deploy. If the ESXi 5.5.x host was deployed by using vSphere Auto Deploy, you can use vSphere Auto Deploy to reprovision the host with a 6.5 image.
vSphere Update Manager.
What is the command to upgrade ESXi bundles?
esxcli software vib update -d /path
What bundles are used for baseline?
Upgrade Baselines - Host & VM Upgrade Baseline
Patch Baselines --Dynamic & Fixed Patch Baseline
Extension Baselines- it's contain 3rd party extension
How do you troubleshoot NIC driver missing issues while installing ESXi?
What is linked mode in virtual center?
How do you retrieve VMX file if its deleted?
How do you retrieve NVRAM file its deleted?
What is the advantage of enabling enhanced vMotion?
What could be the reason if VC installation is failed at the second stage?
What is Cross vCenter migration?
Explain VMware convertor process for both Windows & Linux and prerequisites?
In a ESXI 8 node cluster, if 4 of them are successfully upgraded and 4 of them are failed to upgrade to new version. What is your approach? do you keep failed ones in maintenance mode? or leave them in production?
Can one ESXi cluster can have two different versions?
Yes, no issue with it
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