What are the basic differences between VMware and Hyper-v ?
|Features||VMware vSphere||MS Hyper-V|
|Terminology To Virtual Machines||Distributed/Standard Switch||Virtual Switch|
|DRS – Distributed Resource Scheduler||PRO – Performance & Resource Optimization|
|Separated Power Management||Dynamic Optimization & Core Parking|
|Vmware tools also||Integration component also|
|Service console model||Parent partition model|
|Storage||Raw device in mapping||Pass-Through in mapping|
|Extend/Volume Grow||Expand Volume/Disk|
|Storage in vMotion||Quick Storage Migration|
|Resource Management||Fault Tolerance, Yes||Fault Tolerance, No|
|Application HA, Yes||Application HA, Yes(Failover Clustering)|
|Resource pools, Yes||Resource Pools, Yes(Host Groups)|
|VM Scalability||USB Support, Yes||USB Support, No|
|Supports comprehensive guest OS||Less Guest Support|
|Serial ports are 32 ports||These are only connected to Named pipes|
Q2) What is the hardware version used in VMware ESXi 5.5?
Below is the table showing the different version of hardware used in different VMware products along with their release version
|Hardware Versions in VMware ESXi 5.5|
|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|
|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|
Q3) 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.
Q4) 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.
Q5). 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.
Q6) 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:
1. Automatically optimize and allocate entire pools of resources for maximum hardware utilization and
2. Perform hardware maintenance without any scheduled downtime.
3. Proactively migrate virtual machines away from failing or underperforming servers.
Below are the pre-requisites for configuring vMotion
1. Each host must be correctly licensed for vMotion
2. Each host must meet shared storage requirements
3. 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.
4. A shared storage can be on a Fibre Channel storage area network (SAN), or can be implemented using iSCSI SAN and NAS.
5. 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.
6. Each host must meet the networking requirements
7. Configure a VMkernel port on each host.
8. Dedicate at least one GigE adapter for vMotion.
9. Use at least one 10 GigE adapter if you migrate workloads that have many memory operations.
10. Use jumbo frames for best vMotion performance.
11. Ensure that jumbo frames are enabled on all network devices that are on the vMotion path including physical NICs, physical switches and virtual switches.
Q7) Clone Vs Template in VMware?
Clone: A Copy of virtual machine
-> Can’t be restore the cloned Virtual Machine.
-> Clone of an Virtual Machine also be created while the Virtual Machine is switched on
-> Cloning can be done in two ways namely Full Clone and Linked Clone.
-> A full type 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 master copy or a baseline image of an virtual machine that shall 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 inorder 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 can’t 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.
-> While you are cloning a virtual machine or deploying a virtual machine by a template, resulting cloned virtual machine will be an independent of the original template or virtual machine.
Q8) What is a promiscuous mode in Vmware?
1. Promiscuous mode is a security policy which can be defined at the virtual switch or portgroup leve.
2. 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.
3. 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.
4. 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.
Q9). What is the difference between Thick provision Lazy Zeroed, Thick provision Eager Zeroed and Thin provision?
Thick Provision Lazy Zeroed
1. Creates a virtual disk in a default thick format.
2. Space required for the virtual disk is allocated when the virtual disk is created.
3. 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.
4. 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.
5. You cannot convert a flat disk to a thin disk.
Thick Provision Eager Zeroed
1. A type of thick virtual disk that supports clustering features such as Fault Tolerance.
2. Space required for the virtual disk is allocated at creation time.
3. In contrast to the flat format, the data remaining on the physical device is zeroed out when the virtual disk is created.
4. It might take much longer to create disks in this format than to create other types of disks.
1. It provides on on-demand allocation of blocks of data.
2. 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.
3. With thin provisioning, storage capacity utilization efficiency can be automatically driven up towards 100% with very little administrative overhead.
Q10) 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.
Q11) What is VDI?
1. 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”.
2. Once VDI is used the end user connect to their desktop using a device called thin client.
3. The end user can also connect to their desktop using VMware Horizon View installed on any desktop or mobile devices
Q12) What is VMware HA?
1. VMware HA i.e. High Availability which works on the host level and is configured on the Cluster.
2. 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.
3. VMware HA continuously monitors all ESX Server hosts in a cluster and detects failures.
4. 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,
5.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
Q13) 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.
Q14) What is storage vMotion?
1. Storage vMotion is similar to vMotion in the sense that “something” related to the VM is moved and there is no downtime to the VM guest and end users. However, with SVMotion the VM Guest stays on the server that it resides on but the virtual disk for that VM is what moves.
2. With Storage vMotion, you can migrate a virtual machine and its disk files from one datastore to another while the virtual machine is running.
3. You can choose to place the virtual machine and all its disks in a single location, or select separate locations for the virtual machine configuration file and each virtual disk.
4. During a migration with Storage vMotion, you can transform virtual disks from Thick-Provisioned Lazy Zeroed or Thick-Provisioned Eager Zeroed to Thin-Provisioned or the reverse.
5. Perform live migration of virtual machine disk files across any Fibre Channel, iSCSI, FCoE and NFS storage
Q15) What is VMware DRS and how does it works?
1. Here DRS stands for Distributed Resource Scheduler which dynamically balances resource across various host under Cluster or resource pool.
2. VMware DRS allows users to define the rules and policies that decide how virtual machines share resources and how these resources are prioritized among multiple virtual machines.
3. Resources are allocated to the virtual machine by either migrating it to another server with more available resources or by making more “space” for it on the same server by migrating other virtual machines to different servers.
4. The live migration of virtual machines to different physical servers is executed completely transparent to end-users through VMware VMotion
5. VMware DRS can be configured to operate in either automatic or manual mode. In automatic mode, VMware DRS determines the best possible distribution of virtual machines among different physical servers and automatically migrates virtual machines to the most appropriate physical servers. In manual mode, VMware DRS provides a recommendation for optimal placement of virtual machines, and leaves it to the system administrator to decide whether to make the change.
Q16) What is VMware Fault Tolerance?
1. VMware Fault Tolerance provides continuous availability to applications running in a virtual machine, preventing downtime and data loss in the event of server failures.
2. VMware Fault Tolerance, when enabled for a virtual machine, creates a live shadow instance of the primary, running on another physical server.
3. The two instances are kept in virtual lockstep with each other using VMware vLockstep technology
4. The two virtual machines play the exact same set of events, because they get the exact same set of inputs at any given time.
5. The two virtual machines constantly heartbeat against each other and if either virtual machine instance loses the heartbeat, the other takes over immediately. The heartbeats are very frequent, with millisecond intervals, making the failover instantaneous with no loss of data or state.
6. VMware Fault Tolerance requires a dedicated network connection, separate from the VMware VMotion network, between the two physical servers.
Q17) In a cluster with more than 3 hosts, can you tell Fault Tolerance where to put the Fault Tolerance virtual machine or does it chose on its own?
You can place the original (or Primary virtual machine). You have full control with DRS or vMotion to assign it to any node. The placement of the Secondary, when created, is automatic based on the available hosts. But when the Secondary is created and placed, you can vMotion it to the preferred host.
Q18) How many virtual CPUs can I use on a Fault Tolerant virtual machine ?
vCenter Server 4.x and vCenter Server 5.x support 1 virtual CPU per protected virtual machine.
Q19) What happens if vCenter Server is offline when a failover event occurs?
When Fault Tolerance is configured for a virtual machine, vCenter Server need not be online for FT to work. Even if vCenter Server is offline, failover still occurs from the Primary to the Secondary virtual machine. Additionally, the spawning of a new Secondary virtual machine also occurs without vCenter Server.
Q20) What is the difference between Type 1 and Type 2 Hypervisor?
Type 1 Hypervisor
1. This is also known as Bare Metal or Embedded or Native Hypervisor.
2. It works directly on the hardware of the host and can monitor operating systems that run above the hypervisor.
3. It is completely independent from the Operating System.
4. The hypervisor is small as its main task is sharing and managing hardware resources between different operating systems.
5. A major advantage is that any problems in one virtual machine or guest operating system do not affect the other guest operating systems running on the hypervisor.
6. Examples: VMware ESXi Server, Microsoft Hyper-V, Citrix/Xen Server
Type 2 Hypervisor
1. This is also known as Hosted Hypervisor.
2. In this case, the hypervisor is installed on an operating system and then supports other operating systems above it.
3. It is completely dependent on host Operating System for its operations
4. While having a base operating system allows better specification of policies, any problems in the base operating system a ffects the entire system as well even if the hypervisor running above the base OS is secure.
5. Examples: VMware Workstation, Microsoft Virtual PC, Oracle Virtual Box
Q21) How does vSphere HA works?
When we configure multiple hosts for HA cluster, a single host is automatically elected as the master host. The master host communicates with vCenter Server and monitors the state of all protected virtual machines and of the slave hosts. When you add a host to a vSphere HA cluster, an agent is uploaded to the host and configured to communicate with other agents in the cluster.
Q. What are the monitoring methods used for vSphere HA?
The Master and Slave hosts uses two types of monitoring the status of the hosts
1. Datastore Heartbeat
2. Network Heartbeat
Q22) What are the roles of a master host in vSphere HA?
1. Monitoring the state of slave hosts. If a slave host fails or becomes unreachable, the master host identifies which virtual machines need to be restarted.
2. Monitoring the power state of all protected virtual machines. If one virtual machine fails, the master host ensures that it is restarted. Using a local placement engine, the master host also determines where the restart should be done.
3. Managing the lists of cluster hosts and protected virtual machines.
4. Acting as vCenter Server management interface to the cluster and reporting the cluster health state.
Q23) How is a Master host elected in vSphere HA environment?
When vSphere HA is enabled for a cluster, all active hosts (those not in standby or maintenance mode, or not disconnected) participate in an election to choose the cluster’s master host. The host that mounts the greatest number of datastores has an advantage in the election. Only one master host typically exists per cluster and all other hosts are slave hosts. If the master host fails, is shut down or put in standby mode, or is removed from the cluster a new election is held.
Q24) If the vCenterserver goes down with a situation that it was pre configured with vSphere HA and DRS, so after power down will HA and DRS perform their task?
vSphere HA is not dependent on vCenterserver for its operations as when HA is configured it installs an agent into each host which does its part and is not dependent on vCenterserver. Also HA doesnot uses vMotion, it justs restarts the vms into another host in any case of host failure.
Further vSphere DRS is very much dependent on vCenterserver as it uses vMotion for its action for live migration of vms between multiple hosts so in case vCenterserver goes down the vMotion won’t work leading to failure of DRS.
Q25) What is the use of vmware tools?
VMware Tools is a suite of utilities that enhances the performance of the virtual machine’s guest operating system and improves management of the virtual machine. Without VMware Tools installed in your guest operating system, guest performance lacks important functionality. Installing VMware Tools eliminates or improves these issues:
1. Low video resolution
2. Inadequate color depth
3. Incorrect display of network speed
4. Restricted movement of the mouse
5. Inability to copy and paste and drag-and-drop files
6. Missing sound
7. Provides the ability to take quiesced snapshots of the guest OS
8. Synchronizes the time in the guest operating system with the time on the host
9. Provides support for guest-bound calls created with the VMware VIX AP
- What is VMKernel and why it is important?
VMkernel is a virtualization interface between a Virtual Machine and the ESXi host which stores VMs. It is responsible to allocate all available resources of ESXi host to VMs such as memory, CPU, storage etc. It’s also controlled special services such as vMotion, Fault tolerance, NFS, traffic management and iSCSI. To access these services, VMkernel port can be configured on ESXi server using a standard or distributed vSwitch. Without VMkernel, hosted VMs cannot communicate with ESXi server.
- What is the hypervisor and its 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 by the host. There are two types of hypervisors
- Hosted hypervisor (works as application i-e VMware Workstation)
- Bare-metal (is virtualization software i-e VMvisor, Hyper-V which is installed directly onto the hardware and controls all physical resources).
- What is Virtualization?
The process of creating virtual versions of physical components i-e Servers, Storage Devices, Network Devices on a physical host is called virtualization. Virtualization lets you run multiple virtual machines on a single physical machine which is called ESXi host.
- What are the different types of virtualization?
There are 5 basic types of virtualization
- Server virtualization: consolidates the physical server and multiple OS can be run on a single server.
- Network Virtualization: Provides complete reproduction of physical network into a software-defined network.
- Storage Virtualization: Provides an abstraction layer for physical storage resources to manage and optimize in virtual deployment.
- Application Virtualization: increased mobility of applications and allows migration of VMs from a host on another with minimal downtime.
- Desktop Virtualization: virtualize desktop to reduce cost and increase service
Fault Tolerance (FT)
- What is VMware FT?
FT stands for Fault Tolerance very prominent component of VMware vSphere. It provides continuous availability for VMs when an ESXi host fails. It supports up to 4 vCPUs and 64 GB memory. FT is very bandwidth intensive and 10GB NIC is recommended to configure it. It creates a complete copy of an entire VM such as storage, compute, and memory.
- How many vCPUs can be used for a VM in FT?
In vSphere 6.0, there can be up to 4 vCPUs and 64 GB RAM can be used.
- What is the name of the technology used by VMware FT?
vLockstep technology is used by VMware FT
- What is Fault Tolerant Logging?
The communication between two ESXi hosts is called FT logging when FT is configured between them. The pre-requisition of configuring FT is to configure VMKernel port.
- Will the FT work if vCenter Server goes down?
vCenter server is only required to enable Fault Tolerance on a VM. Once it is configured, vCenter is not required to be in online for FT to work. FT failover between primary and secondary will occur even if the vCenter is down.
- What is the main difference between VMware HA and FT?
The main difference between VMware HA and FT is: 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 communication of VMs hosted on a single physical host. it works like a physical switch automatically detects a VM which want to communicate with other VM on a same physical server.
- What is vDS?
vDS stands for Virtual Distributed Switch acts as a single switch in a whole virtual environment and is responsible to provide central provisioning, administration, and monitoring of the virtual network.
- How many maximum standard ports per host available?
4096 ports per host are available either in a standard switch or distributed switch.
- What are the main benefits of distributed switch (vDS)?
vDS can provide:
- Central administration for a data center
- Central provision, and
- What is VMKernal adapter and why it used?
VMKernel adapter provides network connectivity to the ESXi host to handle network traffic for vMotion, IP Storage, NAS, Fault Tolerance, and vSAN. For each type of traffic such as vMotion, vSAN etc. separate VMKernal adapter should be created and configured.
- What is the main use of port groups in data center virtualization?
You can segregate the network traffic by using port groups such as vMotion, FT, management traffic etc.
- What are three port groups are configured in ESXi networking?
- Virtual Machine Port Group – Used for Virtual Machine Network
- Service Console Port Group – Used for Service Console Communications
- VMKernel Port Group – Used for VMotion, iSCSI, NFS Communications
- What is VLAN and why use in virtual networking?
A logical configuration on the switch port to segment the IP Traffic where each segment cannot communicate with other segments without proper rules mentioned is called VLAN and every VLAN has a proper number called VLAN ID.
- 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 three network security policies/modes on vSwitch?
- Promiscuous mode
- MAC address change
- Forged transmits
- What is promiscuous mode on vSwitch?
The default mode is Reject. If Accept is selected, VM will receive all traffic port group via vSwitch.
- What is MAC address changes network policy?
The default mode of this policy is Reject. If the Accept is selected, a host will accept requests to change the effective MAC address.
- What is Forged transmits network policy?
The default mode is Reject. If Accept is selected, a host will not compare the source and effective MAC address transmitted from a VM.
- What are the main components of vCenter Server architecture?
There are three main components of vCenter Server architecture.
- vSphere Client and Web Client: a user interface.
- vCenter Server database: SQL server or embedded PostgreSQL to store inventory, security roles, resource pools etc.
- SSO: a security domain in a virtual environment
- What is 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 are the two main deploying methods of PSC
You can install PSC in two ways:
- What are different types of vCenter Server deployment?
It has two deployment types
- Embedded Deployment
- External deployment
- What is vRealize Operation (vROP)
vROP provides the operation dashboards for performance analytics, capacity optimization and monitoring the virtual environment.
- What is the basic security step to secure vCenter Server and users?
Authenticate vCenter Server with Active Directory. By using this we can assign specific roles to users and can also manage the virtual environment in an efficient way.
Virtual Storage (Datastore)
- What is datastore?
Datastore is a storage location where virtual machine files are stored and accessed. Datastore is based on a file system which is called VMFS, NFS.
- What is the .vmx file?
It is the configuration file of a VM
- What information .nvram file stores?
It stores BIOS related information of a VM.
- What .vmdk file does and used?
Vmdk is a VM disk file and stores data of a VM. It can be up to 62 TB in size in vSphere 6.0 version.
- How many 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 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 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 datastore to another. During Storage vMotion, virtual disk types think provisioning disk can be transformed to thin provisioned disk.
What’s New in vSphere 6.0
- What is VM Hardware version for vSphere 6.0?
- What VM hardware version for vSphere 6.5?
- In which version of vSphere PSC was introduced?
Platform Services Controller (PSC) is introduced in vSphere 6.0. vSphere 6.0 is also known as Virtual hardware version 11.
- 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 in vCenter Appliance (vCSA).
- How many hosts can be managed by a cluster in vSphere 6.0?
A single cluster can manage maximum 64 hosts
- How can maximum VMs be managed by a single cluster?
A single cluster can manage the maximum of 8000 VMs.
- What is VVol?
Virtual Volume a new VM disk management concept introduced in vSphere 6.0 that enables array-based operations at the virtual disk level. VVol is automatically created when a virtual disk is created in a virtual environment for a VM.
- How many licensing options 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 features of Standard and Enterprise Editions with additionally Fault Tolerance upto 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 upto 12TB of RAM.
- 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 can share on another geographical location of a company without creating again on other locations. It has many benefits such as sharing and consistency, storage efficiency, and secure subscription.
- How many types of Content Libraries have?
It has three types:
- Local: library of local control.
- Published: local library which contents (VM templates, ISO images etc) for subscription.
- Subscribed: A library which syncs with the published library
- What are the requirements and limitations of Content Libraries?
A content library has the following requirements and limitations
- Single storage which can size upto 64TB
- Maximum of 256 items per library
- Sync occurs once every 24 hours
- What is VMFS?
VMFS is a file system for a VM in VMware vSphere. VMFS is a datastore that responsible for storing virtual machine files. VMFS can also store large files which size can up to 64TB in vSphere 6.0
- What is vSAN?
Virtual SAN is a 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.
- What are the different configuration options for VSAN?
There are two configuration options for vSAN:
- Hybrid: Uses both flash-based and magnetic disks for storage. Flash are used for cashing, while magnetic disks are used for capacity or storage.
- All-Flash: Uses flash for both caching and for storage
- Are there VSAN ready nodes are available in the market?
Yes, vSAN-ready such as VxRail 4.0 and 4.5 are available in the market. VxRail is the combination of min 3 servers which are part of a cluster and can scale up to 64 servers.
- How minimum servers/hosts are required to configure vSAN?
To configure a vSAN, you should have minimum 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 disk groups and max magnetic disks are allowed in single disk group?
Maximum 5 disk groups are allowed on an ESXi host which is a part of a vSAN cluster and a maximum of 7 magnetic and 1 SSD per disk group is allowed.
- How many types of storages can we use in our virtual environment?
- Direct Attached Storage
- Fiber Channel (FC)
- 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 a hardware-based either dependent or independent and software-based known as iSCSI software initiator.
- What is the format of iSCSI addressing?
It uses TCP/IP to configure.
- What are iSCSI naming conventions?
iSCSI names are formatted in two different ways:
- the iSCSI qualified name (IQN)
- extended unique identifier (EUI)
- What is vApp?
vApp is a container or group where more than one VM can be package and manage multi-tiered applications for specific requirements for example, Web server, database server, and application server can be configured as a vApp and can be defined their power-on and power-off sequence.
- What settings can be configured for vApp?
We can configure several settings for vApp such as CPU and memory allocation, and IP allocation policy etc.
- What is VMware DRS?
DRS stands for Distributed Resource Scheduler; that automatically balances available resources among various hosts by using cluster or resource pools. With the help of HA, DRS can move VMs from one host to another to balance the available resources among VMs.
- What is share, limit, and reservation?
Share: A value that specifies the relative priority or importance of a VM access to given resource.
Limit: Consumption of a CPU cycle or host physical memory that cannot cross the defined value (limit).
Reservation: This value defines in the form of CPU or memory and must be available for a VM to start.
- What are the alarms why we use them?
An alarm is a notification which appears when an event occurs. Many default alarms exist for many inventory objects. Alarms can be created and modified using vSphere Web Client;
- What are the hot-pluggable devices which can be added while VM is running?
We can add HDDs and NIC while VM is running.
- What is a Template?
When a VM is converted into a format which can be used to create a VM with pre-defined settings is called a template. An installed VM can be converted into a template but it cannot be powered-on.
- What is Snapshot?
To create a copy of a VM with the timestamp as a restore point is called a snapshot. Snapshots are taken when an upgrade or software installation is required. For better performance, a snapshot should be removed after a particular task is performed.
- How to convert a physical machine into a VM?
Three steps are required to convert a physical machine to a VM:
- An agent needs to be installed on the Physical machine
- VI client needs to be installed with Converter Plug-in
- A server to import/export virtual machines
- What is vMotion and what is the main purpose to use it in a virtual environment?
It is a very prominent feature of VMware vSphere used to live migrate running VMs from one ESXi host to another without any downtime. Datastores and ESXi hosts both can be used while vMotion.
- What is the difference between a clone and a template?
A clone is a copy of a virtual machine. By cloning a VM, it will save time if multiple VMs with the same configurations are required to configure. While a template is a master copy of an image created from a VM which can be later used to create many clones. After converting a VM to a template, it can’t be powered-on or edited.
- What monitoring method is used in vSphere HA?
- Network Heartbeat
- Datastore Heartbeat
- How is 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 which 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 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 the ESXi Shell?
It is a command-line interface is used to run repair and diagnostics of ESXi hosts. It can be accessed via DCUI, vCenter Server enable/disable, and via SSH.
- How to run ESXTOP on ESXi host?
To run ESXTOP on an ESXi host, we’ll need two pre-requisites:
- Install vSphere Client on a host where you want to configure
- Enable SSH from DCUI by using “Troubleshooting Options” link
Question 1. Explain The Physical Topology Of Virtual Infrastructure 3 Data Centre?
A typical VMware Infrastructure data center consists of basic physical building blocks such as x86 computing servers, storage networks and arrays, IP networks, a management server and desktop clients.
Question 2. How Do You Configure Clusters, Hosts, And Resource Pools In Vi3?
A cluster is a group of servers working together closely as a single server, to provide high availability, load balancing and high performance. A host is a single x86 computing server with individual computing and memory resources. Resource pools are allocation of the available resources in to pieces for the proper distribution.
Question 3. What Are Resource Pools & What’s The Advantage Of Implementing Them?
A VMware ESX Resource pool is a pool of CPU and memory resources. Inside the pool, resources are allocated based on the CPU and memory shares that are defined. This pool can have associated access control and permissions. Clear management of resources to the virtual machines.
Question 4. Explain Why Vmware Esx Server Is Preferred Over Virtual Server Or Workstation For Enterprise Implementation?
For better resource management as it has a virtualization layer involved in its kernel, which communicates with the hardware directly.
Question 5. In What Different Scenarios Or Methods Can You Manage A Vi3?
Using the Virtual Infrastructure Client we can manage one esx server, using virtual center we can manage more than 1 esx server. And also we can use service console to manage it.
Question 6. Explain Advantages Or Features Of Vmware Virtual Machine File System (vmfs)?
It’s a clustered file system, excellent support for sharing between ESX servers in a cluster.
- Allows access by multiple ESX Servers at the same time by implementing profile locking. SCSI Reservations are only implemented when LUN meta data is updated (e.g. file name change, file size change, etc.)
- Add or delete an ESX Server from a VMware VMFS volume without disrupting other ESX Server hosts.
- LVM allows for adaptive block sizing and addressing for growing files allows you to increase a VMFS volume on the fly (by spanning multiple VMFS volumes) With ESX/ESXi 4 VMFS volumes also can be expanded using LUN expansion Optimize your virtual machine I/O with adjustable volume, disk, file and block sizes. Recover virtual machines faster and more reliably in the event of server failure with Distributed journaling.
Can be shared with up to 32 ESX Servers. Can support LUNs with max size of 2TB and a max VMFS size of 64 TB as of version 4 (vSphere). “There is a VMFS3 limitation where each tree of linked clones can only be run on 8 ESX servers. For instance, if there is a tree of disks off the same base disk with 40 leaf nodes in the tree, all 40 leaf nodes can be simultaneously run but they can only run on up to 8 ESX hosts.” VMFS3 limits files to 262,144 (218) blocks, which translates to 256 GB for 1 MB block sizes (the default) up to 2 TB for 8 MB block sizes.
Question 7. What Are The Types Of Data Stores Supported In Esx 3.5?
ISCSI datastores, FC SAO datastores, Local VMFS, NAS and NFS.
Question 8. How Can You Configure These Different Types Of Data Stores On Esx3.5?
If we have FC cards installed on the esx servers, by going to the storage option, we can scan for the lungs.
Question 9. What Is Vmware Consolidate Backup (vcb)? Explain Your Work Exposure In This Area?
VMware Consolidated Backup is a backup framework, which enables 3rd party tools to take backups.
VCB is used to help you backup your VMware ESX virtual servers. Essentially, VCB is a “backup proxy server”. It is not backup software. If you use VCB, you still need backup software. It is commonly installed on its own dedicated Windows physical server.
Here are the benefits of VMware’s VCB:
- Centralize backups of VMware ESX Virtual Servers.
- Provide file level backups of VMware ESX Virtual Servers both full and incremental (file level backup available to only Windows guests).
- Provide image level backups.
- Prevent you from having to load a backup agent on every Virtual Machine.
- Prevent you from having to shutdown Virtual Machines to get a backup.
- Provides LANFree backup because the VCB server is connected to the SAN through your fibre channel adaptor.
- Provides centralized storage of Virtual Server backups on the VCB server that is then moved to your backup tapes through the 3rd party backup agent you install.
- Reduces the load on the VMware ESX servers by not having to load a 3rd party backup agent on either the VMware ESX service console or on each virtual machine.
- Utilizes VMware Snapshots.
Basically, here is how VCB works:
- If you are doing a file level backup, VCB does a snapshot of the VM, mounts the snapshot, and allows you to backup that mounted “drive” through VCB to your 3rd party backup software.
- If you are doing an image level backup of the VM, VCB does a snapshot of the VM, copies the snapshot to the VCB server, unsnaps the VM, and allows you to backup the copied snapshot image with your 3rd party backup software.
Question 10. How Do You Configure Vmware Virtual Centre Management Server For Ha & Drs? What Are The Conditions To Be Satisfied For This Setup?
HA & DRS are the properties of a Cluster. A Cluster can be created only when more than one host added, in that case we need to configure HA & DRS as well to provide High Availability and Load balancing between hosts and for the virtual machines.
Question 11. Explain Your Work Related To Below Terms?
VM Provisioning: Virtual Machine Creation.
Alarms & Event Management:
- Alarms are used to know the status of the resource usage for a VM.
- Events are used monitor the tasks that are taken place on the esx servers or in the virtual center.
Task Scheduler: Task scheduler, if you want to schedule a task it will be used, for example if you want move one vm from one host to another host or if you want shutdown/reboot a vm etc.
Hardware Compatibility List: what is the hardware that compatible with ESX OS.
Question 12. What San Or Nas Boxes Have You Configured Vmware With? How Did You Do That?
Storage team will provide the LUN information, with that we will add those LUNs to ESX hosts from VM storage.
Question 13. What Kind Of Applications Or Setups You Have On You Virtual Machines?
Exchange server and Share Point, but these are for DEMO purposes, Citrix presentation servers etc.
Question 14. Have You Ever Faced Esx Server Crashing And Virtual Centre Server Crash? How Do You Know The Cause Of These Crashes In These Cases?
Happened when SAN went down. Raid controller was bad. Had to restore VM. Also when a thin provisioned server used almost all of the vmfs volume. Had to move some old powered off VM from VMFS Volume.
Question 15. What Are The Differences Between Esx And Esxi?
ESX is an OS with full features of virtualization; ESXi is a limited features OS with 32MB image.
Question 16. What Is Promiscuous Mode?
If the promiscuous mode is enabled for a switch, the traffic sent that switch will be visible to all vm’s connected to that switch. I mean, the data will be broadcasted.
Question 17. What Makes Iscsi And Fc Different?
Addressing Scheme, iSCSI relies on IP and FC not, and the type of transfer of data also. In FC the data transferred as blocks, in iSCSI the data transferred as files. The cabling also, FC uses Fibre cable and iSCSI uses RJ45.
Question 18. What Is Resource Pool? What Is The Use Of It?
A resource pool is a logical abstraction for flexible management of resources. Resource pools can be grouped into hierarchies and used to hierarchically partition.
Question 19. Ask About How Ha Works?
VMware HA provides high availability for virtual machines by pooling them and the hosts they reside on into a cluster. Hosts in the cluster are monitored and in the event of a failure, the virtual machines on a failed host are restarted on alternate hosts.
Question 20. What Is Virtual Smp?
When and why should you give a vm multiple vCPUs part of their answer would be that best practice is to start with a single vCPUs because of you can run into performance issues due to CPU scheduling.
Question 21. What Are Notable Files That Represent A Vm?
- vmx – configuration settings for VM
- vmxf – configuration settings used to support an XMLbased VM configuration API
- vmtx – configuration settings for a Template VM (replaces the .vmx file)
- vmdk – virtual disk file. (Note: if a thick disk is used, a -flat. Vmdk file that represents the actual monolithic disk file will exist but will be hidden from the vSphere Client.)
- nvram – nonvolatile memory (BIOS)
vswp – swap file used by ESX/ESXi per VM to over commit memory, i.e. use more memory than physically available. This is created by the host automatically when powering on a VM and deleted (default behavior) when powering off a VM. Swap files can remain and take up space if a host failed prior to shutting down a VM properly. Normally the swap file is stored in the location where the VM configuration files are kept; However the location can be optionally located elsewhere
for example: locally for performance reasons and if using NAS/NFS, local swap..vmsssd — sfours psennadp sfhiloet ( mif apnlaacgeedm inetnot suspend power mode) should be used.
Question 22. What Are Host Profiles? What Licensing Is Required For Host Profiles? Available With Vsphere Enterprise Plus Edition?
A set of best practice configuration rules, which are can be applied to entire cluster or to an individual host. So that all the hosts in sync with each other, this will avoid vMotion, drs and ha problems.
Question 23. Can Host Profiles Work With Esx/esxi 3.x Hosts?
No. Only starting with ESX/ESXi 4.0.
Question 24. Can Host Profiles Be Used With A Cluster Running Both Esx And Esxi Hosts?
- Yes, but remember to use an ESX host and not an ESXi host to create a profile for use.
- In theory, Host Profiles should work with mixed host clusters, as it translates ESX to ESXi, but be careful as there are enough differences between ESX and ESXi that can lead you to make self-inflicted errors when applying Host Profiles. The easiest method is to create clusters that are homogeneous and maintain two different profiles for these two types of clusters.
Question 25. Can Host Profiles Work When Using The Cisco Nexus 1000v?
No, because Host Profiles was designed with the generic vNetwork Distributed Switch. The Cisco Nexus 1000v switch gives administrators fine-grained control of the networking beyond what Host Profiles can apply.
Question 26. What Are Host Profiles?
A set of best practice configuration rules, which are can be applied to entire cluster or to an individual host. So that all the hosts in sync with each other, this will avoid vMotion, drs and ha problems.
Question 27. What Is The Use Of A Port Group?
The port group segregates the type of communication.
Question 28. What Are The Type Of Communications Which Requires An Ip Address For Sure?
Service Console and VMKernel (VMotion and iSCSI), these communications does not happen without an ip address (Whether it is a single or dedicated).
Question 29. In The Esx Server Licensing Features Vmotion License Is Showing As Not Used, Why?
Even though the license box is selected, it shows as “License Not Used” until, you enable the VMotion option for specific vSwitch.
Question 30. How The Virtual Machine Port Group Communication Works?
All the vm’s which are configured in VM Port Group are able to connect to the physical machines on the network. So this port group enables communication between vSwitch and Physical Switch to connect vm’s to Physical Machine.
Question 31. Does The Vswitches Support Vlan Tagging? Why?
Yes, then Switches support VLAN Tagging; otherwise if the virtual machines in an esx host are connected to different VLANS, we need to install a separate physical nic (vSwitch) for every VLAN. That is the reason Vmware included the VLAN tagging for vSwitches. So every vSwitch supports upto 1016 ports, and BTW they can support 1016 VLANS if needed, but an ESX server doesn’t support that many VM’s. 🙂
Question 32. What Is Promiscuous Mode On Vswitch? What Happens If It Sets To Accept?
If the promiscuous mode set to Accept, all the communication is visible to all the virtual machines, in other words all the packets are sent to all the ports on vSwitch.
If the promiscuous mode set to reject, the packets are sent to intended port, so that the intended virtual machine was able to see the communication.
Question 33. What Is Mac Address Changes? What Happens If It Is Set To Accept?
When we create a virtual machine the configuration wizard generates a MAC address for that machine, you can see it in the .vmx (VM Config) file. If it doesn’t matches with the MAC address in the OS this setting does not allow incoming traffic to the VM. So by setting Reject Option both MAC addresses will be remains same and the incoming traffic will be allowed to the VM.
Question 34. What Is Forged Transmits? What Happens If It Is Set To Accept?
When we create a virtual machine the configuration wizard generates a MAC address for that machine, you can see it in the .vmx (VM Config) file. If it doesn’t matches with the MAC address in the OS this setting does not allow outgoing traffic from the VM. So by setting Reject Option both MAC addresses will be remains same and the outgoing traffic will be allowed from the VM.
Question 35. What Are The Devices That Can Be Added While The Virtual Machine Running?
- In VI 3.5 we can add Hard Disk and NIC’s while the machine running.
- In vSphere 4.0 we can add Memory and Processor along with HDD and NIC’s while the machine running.
Question 36. How To Set The Time Delay For Bios Screen For A Virtual Machine?
Right Click on VM, select edit settings, choose options tab and select boot option, set the delay how much you want.
Question 37. What Is A Template?
We can convert a VM into Template, and it cannot be powered on once its changed to template. This is used to quick provisioning of VMs.
Question 38. What To Do To Customize The Windows Virtual Machine Clone?
Copy the sysprep files to Virtual center directory on the server, so that the wizard will take the advantage of it.
Question 39. What To Do To Customize The Linux/unix Virtual Machine Clone?
VC itself includes the customization tools, as these operating systems are available as open source.
Question 40. Does Cloning From Template Happens Between Two Data Centers?
Yes. It can, if the template in one datacenter, we can deploy the vm from that template in another datacenter without any problem.
Question 41. What Are The Common Issues With Snapshots? What Stops From Taking A Snapshot And How To Fix It?
- If you configure the VM with Mapped LUN, then the snapshot failed. If it is mapped as virtual then we can take a snapshot of it.
- If you configure the VM with Mapped LUNs as physical, you need to remove it to take a snapshot.
Question 42. What Are The Settings That Are Taken Into To Consideration When We Initiate A Snapshot?
- Virtual Machine Configuration (What hardware is attached to it).
- State of the Virtual Machine Hard Disk file ( To revert back if needed).
- State of the Virtual Machine Memory (if it is powered on).
Question 43. What Are The Requirements For Converting A Physical Machine To Vm?
- An agent needs to be installed on the Physical machine.
- VI client needs to be installed with Converter Plug-in.
- A server to import/export virtual machines.
Question 44. What Is Vmware Consolidated Backup?
It is a backup framework that supports 3rd party utilities to take backups of ESX servers and Virtual Machines. It’s not a backup service.
Question 45. To Open The Guided Consolidation Tool, What Are The User Requirements?
The user must be member of administrator, the user should have “Logon as service” privileges – To give a user these privileges, open local sec policy, select Logon as service policy and add the user the user should have read access to AD to send queries.
Question 46. You’ve Learned Over The Years There’s More To Vsphere Than Server Hardware. What Other 2 Resources Are Just As Important As Servers And Need To Be Properly Planned Out When Designing And Building A Vsphere Cloud?
Storage and network resources are crucial for all vSphere Clouds.
Question 47. Vmware Vsphere Gives You Options. What Are The 4 Typical Ways Storage Can Be Added To A Vsphere?
Storage can be added via iSCSI, FC, NFS and local disk (including DAS).
Question 48. What Is The Best Plan For A Storage Failure That Impacts Multiple Data Stores?
Always have a backup of the VMs on a separate storage environment that can be used to restore the lost virtual servers.
Question 49. Your Host Is A Beast, Dual Socket With 8 Core Cpus And 192 Gb Of Memory. How Many Virtual Servers Can Be Added To A 1tb Datastore?
It depends on the size of the VMs and the performance of the storage. Higher performing storage can be filled to capacity but space should be left for data growth and snapshots. A datastore should never be allowed to fill up 100%.
Question 50. This Is A Tough Vmware Interview Question Created Just For You. Name 4 Things That Happen On The Vmkernel Networking Layer?
vMotion, IP storage (iSCSI/NFS), Fault Tolerance and Virtual SAN.
Question 51. You Have A Vcp So This Should Be An Easy Interview Question. What Are 2 Ways A Vsphere Admin Can Separate Traffic From Distinct Environments (ex. Production And Test) On The Same Hosts?
Either by creating separate vSwitches using dedicated NICs or if NICs are not available by creating separate port groups using different VLAN IDs on the same vSwitch.
Question 52. True Or False. A Distributed Virtual Switch Is Very Much Like A Physical Switch That Detects Which Vms Are Logically Connected To Each Port And Uses That Information To Forward Network Traffic. Hint: It Is Not Used For Monitoring And Administration Across A Data Center?
False. A Distributed Virtual Switch acts as a single switch across all hosts in a data center to provide centralized provisioning, administration, and monitoring of virtual networks.
Question 53. Another True Or False. Nic Teams Are “normally” Put In Active/active Mode To Allow Fail-over In The Event Of A Hardware Failure?
False again. NIC teams are normally put in active/standby mode to allow fail-over in the event of a hardware failure. You can use active/active but this would not be standard and would require port channeling at the physical switch.