VMWARE INTERVIEW QUESTIONS AND ANSWERS -NETWORKING What is Service Console? The service console is developed based up on Redhat Linux Operating system, it is used to manage the VMKernel What are the basic commands to troubleshoot connectivity between vSphere Client / vCenter to ESX server? VMWare Kernel is a Proprietary kernel of vmwareand is not based on any of the flavors of Linux operating systems, . VMkernel requires an operating system to boot and manage the kernel. A service console is being provided when VMWare kernel is booted. Only service console is based up on Red hat Linux OS not VMkernel. What is the use of Service Console port ? Service console port group required to manage the ESX server and it acts as the management network for the ESX. Vcenter /Vsphere Client uses the service console IP's to communicate with the ESX server. What is the use of VMKernel Port ? Vmkernel port is used by ESX/ESXi for vmotion , ISCSI & NFS communications. ESXi uses Vmkernel as the management network since it don't have service console built with it. What is the use of Virtual Machine Port Group ? Virtual Machine port group is used by Virtual machine communication. How Virtual Machine communicates to another servers in Network ? All the Virtual Machines which are configured in VM Port Group are able to connect to the other machines on the network. So this port group enables communication between vSwitch and Physical Switch by the use of uplink (Physical NIC) associated with the port group. What is the default number of ports configured with the Virtual Switch? When the time of Virtual switch created, Vswitch is created with 56 ports by default. We can extend the no of ports by editing the vswitch properties. What are the different types of Partitions in ESX server? / -root Swap /var /Var/core
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VMWARE INTERVIEW QUESTIONS AND ANSWERS -NETWORKING
What is Service Console?The service console is developed based up on Redhat Linux Operating system, it is used to manage the VMKernel
What are the basic commands to troubleshoot connectivity between vSphere Client /vCenter to ESX server?VMWare Kernel is a Proprietary kernel of vmwareand is not based on any of the flavors of Linux operating systems, .VMkernel requires an operating system to boot and manage the kernel. A service console is being provided when VMWare kernel is booted. Only service console is based up on Red hat Linux OS not VMkernel.
What is the use of Service Console port ?Service console port group required to manage the ESX server and it acts as the management network for the ESX.Vcenter/Vsphere Client uses the service console IP's to communicate with the ESX server.
What is the use of VMKernel Port ?Vmkernel port is used by ESX/ESXi for vmotion, ISCSI & NFS communications. ESXi uses Vmkernel as the management network since it don't have service console built with it.
What is the use of Virtual Machine Port Group?Virtual Machine port group is used by Virtual machine communication.
How Virtual Machine communicates to another servers in Network ?All the Virtual Machines which are configured in VM Port Group are able to connect to the other machines on the network. So this port group enables communication between vSwitch and Physical Switch by the use of uplink (Physical NIC) associated with the port group.
What is the default number of ports configured with the Virtual Switch?When the time of Virtual switch created, Vswitch is created with 56 ports by default. We can extend the no of ports by editing the vswitch properties.
What are the different types of Partitions in ESX server?/ -rootSwap/var/Var/core/opt/home/tmp
What are the security options available for ESX vswitch?Promiscuous Mode - RejectMAC Address changes - AcceptForged Transmits - Accept
What is Promiscuous Mode ?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. It can be useful when you are running virtual machines with network sniffers to capture packet in that network.
What is MAC Address changes?All the virtual machines nics are provide with the MAC address at the time of creation and it is stored in .VMX file. If the packet doesn't match with the MAC address as same as in the .VMX file , it does not allow incoming traffic to the VM by setting this option as reject.
If it is set as Accept,ESX accepts requests to change the effective MAC address to other than the MAC address save din the .VMX file.
What is Forged Transmits ?Which is same as the Mac Address changes setting but it worked for the outgoing traffic but the MAC address changes setting is for incoming traffic.
What is a VLAN ?A VLAN is the Virtual LAN which is used to broke down the Broadcast traffic into many logical groups. Basically, one physical switch comprise of one broadcast domain. VLAN used to separate the one broadcast domain into many small pieces to separate the networks within the broadcast domain.
What are the types of VLAN tagging in Vsphere?There are 3 types of VLAN tagging available in Vsphere.1.Virtual Switch Tagging (VST)2.External Switch Tagging (EST)3.Virtual Guest Tagging (VGT)
What are the Traffic Shaping policies available in the Vswitch?Traffic shaping policies are disabled by default. There are 3 different traffic shaping policy settingAverage BandwidthPeak BandwidthBurst Size
Average Bandwidth is defined in KBPSPeak bandwidth is defined in KBPSBurst Size is defined in Kilobytes
What are the Load balancing policies available in vswitch?Route based on the originating virtual switch port IDRoute based on source MAC hashRoute based on IP hash
Route based on the originating virtual switch port ID - Chooses an uplink based on the virtual port where the traffic entered the virtual switch. The traffic will be always send with that same uplink until that particular uplink is failed and failed over to another NIC.
Route based on source MAC hash - Choose an uplink based on a hash of the source Ethernet MAC address.The traffic will be always send with that same uplink until that particular uplink is failed and failed over to another NIC.
Route based on IP hash - Choose an uplink based on a hash of the source and destination IP addresses of each packet.
What are the types for Network Failover Detection settings?Link Status onlyBeacon Probing
Link Status only - Relies solely on the link status provided by the network adapter. This detects failures, such as cable pulls and physical switch power failures, but it cannot detect configuration errors, such as a physical switch port being blocked by spanning tree or misconfigured to the wrong VLAN or cable pulls on the other side of a physical switch.
Beacon Probing - Sends out and listens for beacon probes — Ethernet broadcast frames sent by physical adapters to detect upstream network connection failures — on all physical Ethernet adapters in the team. In addition to link status, to determine link failure. This detects many of the failures which are not detected by Link Status.
DIFFERENCE BETWEEN ESX 3.5 AND ESX 4.0
Features ESX 3.5 ESX 4
Linked Mode No Linked Mode SupportLinked Mode Supportis introduced in
vSphere 4.0
Host Profiles No Host ProfilesHost Profiles is Introduced in vSphere
4.0
Centralized License Require dedicated License serverLicense can be managed within vCenter
serverPerformance chart Yes Lot More enhancementsEvents and Alarms Yes Lot More enhancements
Fault tolerance Not Available Available from vSphere 4.0
Storage VMotionSVMotion available only with
CLI SVMotion available in GUIVMotion Yes Yes
Virtual CPUs per host 192 512Virtual Machines per host 170 320
Logical processors per host 32 64RAM per host 256 GB 1 TB
Maximum Service console Memory 800 MB 800 MB
DRS Yes Yes
VMware Data RecoveryBackup using VCB (VMware
Consolidated backup)VMware Data Recovery and VCB
supportEnhanced VMotion
Compatibility (EVC) No EVC EVC is introduced in vSphere 4.0
VMware HA Admission Control
Yes but without options to reserve failover capacity
Admission Control is improved to provide more flexible configuration options to reserve failover capacity.
High Availability Clustering with Windows Server 2000,
2003, 2008 Not Available Available in vSphere 4.0
Serial Attached SCSI (SAS) Not Available Available to support MSCS on win 2008Hosts per storage volume 32 64
Fiber Channel paths to LUN 32 16NFS Datastores 32 64
Hardware iSCSI initiators per host 2 4
Virtual Machine Hot Add Support NO Yes
Number of virtual CPUs per virtual machine 4 8
Virtual Hardware version 4 7RAM per virtual machine 64 GB 255 GB
virtual machine swap file Size 65532MB 255GBVMDirectPath for Virtual
Machines NO Yes
Vmkernel 32 Bit 64 bitService Console 32 Bit 64 bit
Concurrent remote console sessions 10 40
Virtual Disk Thin Provisioning No Thin ProvisioningThin Provisioning introduced in vSphere
4.0
VMware Paravirtualized SCSI (PVSCSI Not available
High-performance storage adapters that offer greater throughput and lower CPU
utilization for virtual machinesHot Extend for Virtual Disks Only Via VCLI using vmkfstools Available via GUIHot plug support for virtual
devices No YesVMXNET Generation 3 Not Available Yes
vNetwork Distributed Switch Not AvailableAvailable from vSphere with Enterprise
Plus LicensePrivate VLAN Support Not Available Available with DVSwitch
Network Vmotion Not Available Available with DVSwitch3rd Party Distributed Switch
Support Not AvailableWe can use Cisco Nexus 1000v with
DVSwitchIPv6 Support Yes YesNICs per VM 4 10
Standard vSwitches per host 127 248Virtual NICs per standard
vSwitch 1016 40888 way SMP No Only 4 way Yes
Update Manager Yes Yes
DPM ExperimentalFully supported with PMI and iLO
Remote Power On
License Types
VMware Infrastructure Foundation VMware
Infrastructure Standard VMware Infrastructure Enterprise
vSphere Essentials vSphere Essentials Plus vSphere Standard vSphere
Advanced vSphere Enterprise vSphere Enterprise Plus
DIFFERENCE BETWEEN VSPHERE 4.1 AND VSPHERE 5vSphere 4.1 vSphere 5.0
HA Failure Detection Management N/WManagement N/W and Storage
communicationHA Log File /etc/opt/vmware/AAM /etc/opt/vmware/FDMDNS Dependent on DNS Yes NO
Host UEFI boot support NOboot systems from hard drives, CD/DVD
drives, or USB mediaStorage DRS Not Available YesVM Affinity & Anti-Affinity Available AvailableVMDK Affinity & Anti-Affinity Not Available AvailableProfile driven storage Not Available AvailableVMFS version VMFS-3 VMFS-5VSphere Storage Appliance Not Available Available
Iscsi Port BindingCan be only done via Cli
using ESXCLI
Configure dependenthardware iSCSI and softwareiSCSI adapters along with thenetwork configurations and
port binding in a single dialog box using the vSphere Client.
Storage I/O control for NFS Fiber Channel Fiber Channel & NFSStorage Vmotion Snapshot support
VM with Snapshot cannot be migrated using Storage vMotion
VM with Snapshot can be migrated using Storage vMotion
Swap to SSD NO YesNetwork I/O control Yes Yes with enhancementESXi firewall Not Available YesvCenter Linux Support Not Available vCenter Virtual AppliancevSphere Full Client Yes YesvSphere Web Client Yes yes with lot of improvementsVM Hardware Version 7 8Virtual CPU per VM 8 vCpu 32 vCpuVirtual Machine RAM 255 GB 1 TB of vRAMVM Swapfile size 255 GB 1 TBSupport for Client connected USB Not Available YesNon Hardware Accelerated3D grpahics support Not Available YesUEFI Virtual BIOS Not Available YesVMware Tools Version 4.1 5Mutlicore vCpu Not Available Yes configure at VM settingMAC OS Guest Support Not Available Apple Mac OS X Server 10.6Smart card reader support for Not Available Yes
VMAuto Deploy Not Available YesImage Builder Not Available YesVM's per host 320 512Max Logical Cpu per Host 160 160RAM per Host 1 TB 2 TBMAX RAM for Service Console 800 MB Not Applicable (NO SC)LUNS per Server 256 256
Metro VmotionRound-trip latencies of up to
5 milliseconds.
Round-trip latencies of up to10 milliseconds. This provides better
performance overlong latency networks
Storage VmotionMoving VM Files using moving
to using dirty block trackingMoving VM Files using I/O
mirroring with better enhancements
Virtual Distributed Switch Yes
Yes with more enhancementslike deeper view into virtual machine traffic through Netflow and enhances
monitoring and troubleshooting capabilities through SPAN and LLDP
USB 3.0 Support NO YesHost Per vCenter 1000 1000Powered on virtual machines per vCenter Server 10000 10000Vmkernel 64-bit 64-bitService Console 64-bit Not Applicable (NO SC)
Management Network Service Console Interface VMKernel Interface
Jumbo Frames Supported Supported
Hardware Montioring3 rd Party agents installed in
Service consoleVia CIM Providers
Boot from SAN Supported in ESX Supported in ESXi
Software patches and updates
Needed as smilar to linux operation system
Few pacthes because of small footprint and more secure
vSphere web Access Only experimentalFull managenet capability via vSPhere web
client
Locked Down Mode Not presentPresent . Lockdown mode prevents remote
users to login to the host
Scripted Installtion Supported Supported
vMA Support Yes Yes
Major Administration command-line Command
esxcfg- esxcli
Rapid deployment via Auto Deploy
Not supported Supported
Custom Image creation Not supported Supported
VMkernel Network Used forvMotion,Fault
Tolarance,Stoarge Connectivity
Management Network , vMotion, Fault Tolarance, Stoarge Connectivity, ISCSI port
binding
DIFFERENCE BETWEEN VMFS 3 AND VMFS 5 VMFS 5 is available as part of vSphere 5. VMFS 5 is introduced with lot of performance enhancements. Newly installed ESXi 5 will be formatted with VMFS 5 version but if you have upgraded the ESX 4 or ESX 4.1 to ESXi 5, then datastore version will be VMFS 3 only. You will able to upgrade the VMFS 3 to VMFS 5 via vSphere client once ESXi upgrade is Complete. This posts tells you some major differences between VMFS 3 and VMFS 5
Capability VMFS 3 VMFS 5Maximum single Extend size 2 TB less 512 bytes 64 TB
Maximum size of RDM in Virtual Compatibiltiy 2 TB less 512 bytes 2 TB less 512 bytes
Maximum size of RDM in Phsical Compatibiltiy 2 TB less 512 bytes 64 TB
Supported Hosts versions ESX/ESX 3.X, 4.X & 5.x Only ESXi 5 is supported
Spanned Volume size64 TB (32 extends with max
size of extent is 2 TB)64 TB (32 extends with any size combination)
Upgrade path VMFS 3 to VMFS 5Latest Version. NO upgarde
available yet.File Limit 30,000 100,000
Sub-Block size 64 KB 8 KB
DIFFERENCE BETWEEN UPGRADED VMFS 5 AND NEWLY CREATED VMFS 5This post explains you the major difference between VMFS 5 datastore upgrade from VMFS 3 and newly created VMFS 5 datastore. VMFS 5 is available as part of vSphere 5. VMFS 5 is introduced with lot of performance enhancements. Newly installed ESXi 5 will be formatted with VMFS 5 version but if you have upgraded the ESX 4 or ESX 4.1 to ESXi 5, then datastore version will be VMFS 3 only. You will able to upgrade the VMFS 3 to VMFS 5 via vSphere client once ESXi upgrade is Complete. Even though the upgraded datastore will be with VMFS 5 version but there are many technical difference between upgraded VMFS 5 and newly created VMFS 5. This posts tells you some major differences between upgraded VMFS 5 and newly created VMFS 5.
Partition Sector partition starting on sector 128 partition starting on sector 2,048Maximum size of RDM in
Virtual Compatibility 2 TB less 512 bytes 2 TB less 512 bytesMax size of file 2 TB less 512 bytes 2 TB less 512 bytes
What is the difference between Clone and Template?
Clone TemplateClone creates an exact copy of a running Virtual Machine at the time of cloning process
Template acts as a baseline image with the predefined configuration as per organization standards
Cloning a virtual machine creates a exact duplicate copy of the virtual machine with the same configuration and installed software without performing any additional settings.
Create a template to create a master image of a virtual machine from which you can deploy multiple virtual machines
You can create a clone of existing installed and Configured running virtual machine by right clicking the VM and Clone.
You can create a template by converting a virtual machine to a template, cloning a virtual machine to a template, or cloning another template
VM clones are best suited in test and development environments where you want to create, test and work with exact copies of production servers without disturbing production servers by creating clone of the production virtual machine.
Templates are best suited for production environments where you want the mass deployment of virtual machines along with the installed OS and basic software, configured policy as per the security policy of your organization as a base Machine. Once template is deployed, you can install software depend on the role of the server like IIS,Database
VM Clones are not suited for mass deployment of Virtual Machines
Templates are best suited for Mass Deployment of Virtual Machines
We Cannot Convert back the Cloned 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 deployment of virtual machines with latest patches.
Cloned Virtual Machine Can be powered on Templates cannot be powered on
You cannot Clone a Virtual Machine if you have connected directly to ESX/ESXi host using vSphere Client
You cannot create a template of a Virtual Machine if you have connected directly to ESX/ESXi host using vSphere Client
You can customize the guest operating system of the clone to change the virtual machine name, network settings, and other properties. This prevents conflicts that can occur if a virtual machine and a clone with identical guest operating system settings are deployed simultaneously.
You can also Customize the guest operating system while deploying from template
Clone of a virtual machine can be created when the virtual machine is powered on
Convert virtual Machine to template cannot be performed, when Virtual machine is powered on. Only Clone to Template can be performed when VM is powered on
.
What is VMware HA?As per VMware Definition,VMware® High Availability (HA) provides easy to use, cost effective high availability for applications running in virtual machines. In the event of server failure, affected virtual machines are automatically restarted on other production servers with spare capacity
What is AAM in HA?AAM is the Legato automated availability management. Prior to vSphere 4.1, VMware's HA is actually re engineered to work with VM's with the help of Legato's Automated Availability Manager (AAM) software. VMware's vCenter agent (vpxa) interfaces with the VMware HA agent which acts as an intermediary to the AAM software. From vSphere 5.0, it uses an agent called “FDM” (Fault Domain Manager).
What are pre-requites for HA to work?1.Shared storage for the VMs running in HA cluster2.Essentials plus, standard, Advanced, Enterprise and Enterprise Plus Licensing3.Create VMHA enabled Cluster4.Management network redundancy to avoid frequent isolation response in case of temporary network issues (preferred not a requirement)
What is maximum number of primary HA hosts in vSphere 4.1?Maximum number of primary HA host is 5. VMware HA cluster chooses the first 5 hosts that joins the cluster as primary nodes and all others hosts are automatically selected as secondar nodes.
How to see the list of Primary nodes in HA cluster?View the log file named "aam_config_util_listnodes.log" under /var/log/vmware/aam using the below command
What is the command to restart /Start/Stop HA agent in the ESX host?service vmware-aam restart
service vmware-aam stop
service vmware-aam start
Where to located HA related logs in case of troubleshooting?/Var/log/vmware/aam
What the basic troubleshooting steps in case of HA agent install failed on hosts in HA cluster?
1. Check for some network issues2. Check the DNS is configured properly3. Check the vmware HA agent status in ESX host by using below commands service vmware-aam status
4. Check the networks are properly configured and named exactly as other hosts in the cluster. otherwise, you will get the below errors while installing or reconfiguring HA agent.5. Check HA related ports are open in firewall to allow for the communication Incoming port: TCP/UDP 8042-8045 Outgoing port: TCP/UDP 2050-22506. First try to restart /stop/start the vmware HA agent on the affected host using the below commands. In addition u can also try to restart vpxa and management agent in the Host. service vmware-aam restart service vmware-aam stop service vmware-aam start7. Right Click the affected host and click on "Reconfigure for VMWare HA" to re-install the HA agent that particular host.8. Remove the affected host from the cluster. Removing ESX host from the cluster will not be allowed untill that host is put into maintenance mode.9.Alternative solution for 3 step is, Goto cluster settings and uncheck the vmware HA in to turnoff the HA in that cluster and re-enable the vmware HA to get the agent installed.10. For further troubleshooting , review the HA logs under /Var/log/vmware/aam directory.
What is the maximum number of hosts per HA cluster?Maximum number of hosts in the HA cluster is 32
What is Host Isolation?VMware HA has a mechanism to detect a host is isolated from rest of hosts in the cluster. When the ESX host loses its ability to exchange heartbeat via management network between the other hosts in the HA cluster, that ESX host will be considered as a Isolated.
How Host Isolation is detected?In HA cluster, ESX hosts uses heartbeats to communicate among other hosts in the cluster.By default, Heartbeat will be sent every 1 second.If a ESX host in the cluster didn't received heartbeat for for 13 seconds from any other hosts in the cluster, The host considered it as isolated and host will ping the configured isolation address(default gateway by default). If the ping fails, VMware HA will execute the Host isolation response
What are the different types isolation response available in HA?
Power off – All the VMs are powered off , when the HA detects that the network isolation occursShut down – All VMs running on that host are shut down with the help of VMware Tools, when the HA detects that the network isolation occurs.If the shutdown via VMWare tools not happened within 5 minutes, VM's power off operation will be executed. This behavior can be changed with the help of HA advanced options. Leave powered on – The VM's state remain powered on or remain unchanged, when the HA detects that the network isolation occurs.How to add additional isolation address for redundancy?
By default, VMWare HA use to ping default gateway as the isolation address if it stops receiving heartbeat.We can add an additional values in case if we are using redundant service console both belongs to different subnet.Let's say we can add the default gateway of SC1 as first value and gateway of SC2 as the additional one using the below value
1. Right Click your HA cluster2. Goto to advanced options of HA3. Add the line "das.isolationaddress1 = 192.168.0.1"4. Add the line "das.isolationaddress2 = 192.168.1.1" as the additional isolation address
What is HA Admission control?VCenter Server uses admission control to ensure that sufficient resources are available in a cluster to provide failover protection and to ensure that virtual machine resource reservations are respected.
What are the 2 types of settings available for admission control?
Enable: Do not power on VMs that violate availability constraintsDisable: Power on VMs that violate availability constraints
What are the different types of Admission control policy available with VMware HA?There are 3 different types of Admission control policy available.
Host failures cluster toleratesPercentage of cluster resources reserved as fail over spare capacitySpecify a fail over hostHow the Host Failures cluster tolerates admission control policy works?
Select the maximum number of host failures that you can afford for or to guarantee fail over. Prior vSphere 4.1, Minimum is 1 and the maximum is 4.In the Host Failures cluster tolerates admission control policy , we can define the specific number of hosts that
can fail in the cluster and also it ensures that the sufficient resources remain to fail over all the virtual machines from that failed hosts to the other hosts in cluster. VMware High Availability(HA) uses a mechanism called slots to calculate both the available and required resources in the cluster for a failing over virtual machines from a failed host to other hosts in the cluster.
What is SLOT?"A slot is a logical representation of the memory and CPU resources that satisfy the requirements for any powered-on virtual machine in the cluster."If you have configured reservations at VM level, It influence the HA slot calculation. Highest memory reservation and highest CPU reservation of the VM in your cluster determines the slot size for the cluster.
How to Check the HA Slot information from vSphere Client?Click on Cluster Summary Tab and Click on "Advanced Runtime Info" to see the the detailed HA slots information.
What is use of Host Monitoring status in HA cluster?
Let's take an example, you are performing network maintenance activity on your switches which connects your one of th ESX host in HA cluster.what will happen if the switch connected to the ESX host in HA cluster is down?It will not receive heartbeat and also ping to the isolation address also failed. so, host will think itself as isolated and HA will initiate the reboot of virtual machines on the host to other hosts in the cluster. Why do you need this unwanted situation while performing scheduled maintenance window.To avoid the above situation when performing scheduled activity which may cause ESX host to isolate, remove the check box in " Enable Host Monitoring" until you are done with the network maintenance activity.
How to Manually define the HA Slot size?
By default, HA slot size is determined by the Virtual machine Highest CPU and memory reservation. If no reservation is specified at the VM level, default slot size of 256 MHZ for CPU and 0 MB + memory overhead for RAM will be taken as slot size. We can control the HA slot size manually by using the following values.
There are 4 options we can configure at HA advanced options related to slot sizedas.slotMemInMB - Maximum Bound value for HA memory slot sizedas.slotCpuInMHz - Maximum Bound value for HA CPU slot Sizedas.vmMemoryMinMB - Minimum Bound value for HA memory slot sizedas.vmCpuMinMHz - Minimum Bound value for HA CPU slot size
How the "Percentage of cluster resources reserved as failover spare capacity" admission control policy works?
In the Percentage of cluster resources reserved as failover spare capacity admission control policy, We can define the specific percentage of total cluster resources are reserved for failover.In contrast to the "Host Failures cluster tolerates admission control policy", It will not use slots. Instead This policy calculates the in the way below
1.It calculates the Total resource requirement for all Powered-on Virtual Machines in the cluster and also calculates the total resource available in host for virtual machines.2.It calculates the current CPU and Memory Failover capacity for the capacity.3.If the current CPU and Memory Failover capacity for the cluster < configured failover capacity (ex 25 %)4.Admission control will not allow to power on the virtual machine which violates the availability constraints.
How the "Specify a failover host" admission control policy works?
In the Specify a failover host" admission control policy, We can define a specific host as a dedicated failover host. Whenisolation response is detected, HA attempts to restart the virtual machines on the specified failover host.In this Approach, dedicated failover hist will be sitting idle without actively involving or not participating in DRS load balancing.DRS will not migrate or power on placement of virtual machines on the defined failover host.
What is VM Monitoring status?HA will usually monitors ESX hosts and reboot the virtual machine in the failed hosts in the other host in the cluster in case of host isolation but i need the HA to monitors for Virtual machine failures also. here the feature called VM monitoring status as part of HA settings.VM monitoring restarts the virtual machine if the vmware tools heartbeat didn't received with the specified time using Monitoring sensitivity.
What is VMware Fault Tolerance?VMware Fault Tolerance is a component of VMware vSphere and it provides continuous availability to applications by preventing downtime and data loss of Virtual machines in the event of ESX server failures.
What is the name of the technology used by VMware FT?VMware FT using a technology called vLockstep technology
How do i check my host for FT compatibility from vSphere client?One way from vSphere client is to run the cluster complaince check from profile compliance tab of your cluster. The below checks as specified below will be performed as part of the compliance check.Validate that Fault Tolerancelogging NIC speed is at least 1000 Mbps.Validate that power management is supported on the hostValidate that Fault Tolerance logging is enabled.Validate that VMotion NIC speed is at least 1000 Mbps.Validate that all the hosts in the cluster have the same build for Fault ToleranceValidate that the host hardware supports Fault Tolerance.Validate that VMotion is enabled.Validate that at least one shared datastore exists
Another way is to check the summary tab of the ESX/ESXi host, "Host Configured for FT" yes or NO.
If " Host Configured for FT" is No. It will display the items required for that particular ESX for FT to work.
What is FT Logging Traffic?FT logging is the one of option in VMkernel port setting which is similar to enable vmotion option in the vmkernel port. when FT is enabled for the virtual machine, all the inputs (disk read.. wirte,etc..) of the primary virtual machine are recorded and sent to the secondary VM over via FT logging enabled VMkernel port.
How to Enable FT Logging in VMkernel Port?GO the ESX host -> Configuration-> Networking -> Properties of Virtual switch with the VMkernel portgroup configuredClick on VMkernel Port -> click on Edit -> General tab -> select the Fault Tolerance Logging -> click on OK.
How do you configure or enable FT for the virtual machine ?FT can be enabled only per virtual machine basis not at the cluster or ESX level.Right-click the virtual Machine -> Fault Tolerance -> Turn on Fault Tolerance
How does the FT enabled virtual machine will be differentiated with non FT VM's in vSphere client?FT Enabled Virtual machine will appear in Dark Blue colour as compared to non-protected virtual machines.
By default, Only Primary virtual machine will appear under the cluster and ESX host. To take a look at the secondary VM , Go to Virtual Machines tab of the Cluster or Host.
How Does VMware Fault Tolerance Work?When you enable Fault Tolerance for the virtual machine, a secondary virtual machine will be created to work with the primary virtual machine in which you have enabled FT. The primary and secondary virtual machine resides on a different ESX hosts in the cluster. Whatever the events or actions performed by the primary VM will be transmitted via gigabit Ethernet network to be replayed by the secondary virtual machine using VLockstep technology. Eventhough both the primary and secondary virtual machines appear as a single entity and access a common disk, both running with the single IP address, MAc address but writes are only performed by the primary virtual machine.The primary and secondary virtual machines sends heartbeat between each other frequently with millisecond intervals to the check for the availability. If either of the virtual machine loses the heartbeat, other virtual machine will take over the primary virtual machine role immediately.
What happens when you enabled Fault Tolerance for your virtual machine?When you enable Fault Tolerance for the virtual machine, a secondary virtual machine (live shadow image of the primary) will be created to work with the primary virtual machine in which you have enabled FT. The primary and secondary virtual machine resides on a different ESX hosts in the cluster.
What will happen when the ESX host of primary VM failed?When a failure is detected on the primary VM's ESX host, the secondary virtual machine which is running on the another ESX server in the same cluster will takes the place of the first one with the least possible interruption of service.
If vCenter is down, will the FT work?vCenter server is only required to enable FT on the virtual machine.once it is configured, vCenter is not required to be in online for FT to work. FT failover between primary and secondary will occure even if the vCenter is down.
How does Vmware FT differs from VMware HA?1.VMware HA is enabled per cluster basis but FT is enabled per VM basis.
2. In case of ESX host failure, virtual machines in the failed host are restarted and powered-on on the other active hosts in HA cluster. So the restart duration of the virtual machine is the downtime for the virtual machine in HA cluster. But in FT enabled virtual machine, there is no downtime. In case of host failure, secondary VM will become primary and continuing the execution from the exact point where the primary VM is left off or failed. It happens automatically without data loss, without downtime and with a little delay. Users will not see any interruption.
How do you see the summary status of the FT enabled virtual machines in the ESX host from vsphere client?Click on Summary tab of the ESX host -> Fault tolerance information and VM counts will be displayed
1. VMWare Kernel is a Proprietary Kenral and is not based on any of the UNIX operating systems, it's a kernel developed by VMWare Company.
2. The VMKernel can't boot it by itself, so that it takes the help of the 3rd party operating system. In VMWare case the kernel is booted by RedHat Linux operating system which is known as service console.
3. The service console is developed based up on Redhat Linux Operating system, it is used to manage the VMKernel
4. To restart webaccess service on vmwareservice vmware-webaccess restart – this will restart apache tomcat app
5. To restart ssh service on vmwareservice sshd restart
6. To restart host agent(vmware-hostd) on vmware esx serverservice mgmt-vmware restart 7. Path for the struts-config.xml/usr/lib/vmware/webAccess/tomcat/apache-tomcat-5.5.17/webapps/ui/WEB-INF/ - See more at: http://www.01world.in/p/vmware-admin-interview-questions.html#sthash.hRKU2TEE.dpuf
9. Virtual Network in SimpleVirtual Nic(s) on Virtual Machine(s) -----> Physical Nic on the ESX Server (Virtual Switch - 56 Ports) ----->Physical Switch Port Should be trunked with all the VLANS to which the VM's need access
All the ESX servers should be configured with Same number of Physical Nics (vSwitches) and Connectivity also should be same, So that vMotion succeedsAll the Virtual Machines are connected to one vSwitch with Different VLANS, this means the Physical
Nic(vSwitch) needs to be trunked with the same VLANS on the Physical Switch Port
10 What are the three port groups present in ESX server networking 1. Virtual Machine Port Group - Used for Virtual Machine Network 2. Service Console Port Group - Used for Service Console Communications 3. VMKernel Port Group - Used for VMotion, iSCSI, NFS Communications
11. What is the use of a Port Group?The port group segregates the type of communication.
12. 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)
13. 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
14. How the Virtual Machineort group communication works ? All the vm's which are configured in VM Port Group are able to connect to the physical machines on the network. So this port group enables communication between vSwitch and Physical Switch to connect vm's to Physical Machine's
15. what is vlan ?
A vlan is logical configuration of group of segment
16. Does the vSwitches support VLAN Tagging? Why? Yes, The vSwitches support VLAN Tagging, otherwise if the virtual machines in an esx host are connected to different VLANS, we need to install a separate physical nic (vSwitch) for every VLAN. That is the reason vmware included the VLANtagging 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. :)
17. What is Promiscuous Mode on vSwitch ? What happens if it sets to Accept? If the promiscuous mode set to Accept, all the communication is visible to all the virtual machines, in other words all the packets are sent to all the ports on vSwitch If the promiscuous mode set to Reject, the packets are sent to inteded port, so that the intended virtual machine was able to see the communication.
18. 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.
19. 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.
20. What are the core services of VC ?VM provisioning , Task Scheduling and Event Logging
21. Can we do vMotion between two datacenters ? If possible how it will be?Yes we can do vMotion between two datacenters, but the mandatory requirement is the VM should be powered off.
22. What is VC agent? and what service it is corresponded to? What are the minimum req's for VC agent installation ?VC agent is an agent installed on ESX server which enables communication between VC and ESX server.The daemon associated with it is called vmware-hostd , and the service which corresponds to it is called as mgmt-vmware, in the event of VC agent failure just restart the service by typing the following command at the service console
" service mgmt-vmware restart " VC agent installed on the ESX server when we add it to the VC, so at the time of installtion if you are getting an error like " VC Agent service failed to install ", check the /Opt size whether it is sufficient or not.
23. How can you edit VI Client Settings and VC Server Settings ?Click Edit Menu on VC and Select Client Settings to change VI settingsClick Administration Menu on VC and Select VC Management Server Configuration to Change VC Settings
24. 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
25. What are the devices that can be added while the virtual Machine runningIn 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
26. 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.
27. What is a template ?We can convert a VM into Template, and it cannot be powered on once its changed to template. This is used to quick provisioning of VM's.
23. 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.
24. 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.
25. Does cloning from template happens between two datacenters ?Yes.. it can, if the template in one datacenter, we can deploy the vm from that template in another datacenter
without any problem.
26. What are the common issues with snapshots? What stops from taking a snapshot and how to fix it ?If you configure the VM with Mapped LUN's, then the snapshot failed. If it is mapped as virtual then we can take a snapshot of it.If you configure the VM with Mapped LUN's as physical, you need to remove it to take a snapshot.
27. 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)
28. What are the requirements for Converting a Physical machine to VM ?An agent needs to be installed on the Physical machineVI client needs to be installed with Converter Plug-inA server to import/export virtual machines
29. What is VMWare consolidated backup ?It is a backup framework, that supports 3rd party utilities to take backups of ESX servers and Virtual Machines. Its not a backup service.
30. 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
1.What are the products included in VMware vSphere 5.5 Bundle ?
VMware ESXi
VMware vCenter Server
VMware vSphere Client and Web Client
vSphere Update Manager
VMware vCenter Orchestrator
2.What type of Hyper-visor VMware ESXi is ?
VMware ESXi is Bare-metal hypervisor. You can directly install on server hardware.
3.What is the role of VMware vCenter server?
vCenter provides a centralized management platform and framework for all ESXi hosts and their respective
VMs. vCenter server allows IT administrators to deploy, manage, monitor, automate, and secure a
virtual infrastructure in a centralized fashion. To help provide scalability , vCenter Server leverages a back-end
database (Microsoft SQL Server and Oracle are both supported, among others) that stores all the data about the
hosts and VMs.
4. Is it possible install vCenter server on Linux hosts ?
No.But Pre-build vCenter appliance is available in VMware portal which is Linux based.You can import the
appliance as virtual machine.
5.How to update the VMware ESXi hosts with latest patches ?
We can update the ESXi hosts using VMware Update Manager(VUM). We can use this VUM add-on package
on Windwos based vCenter server and Linux based vCenter server (vCenter appliance)
6.What is the use of VMware vSphere Client and vSphere Web Client ?
vCenter Server provides a centralized management framework to VMware ESXi hosts.To access vCenter
server, you need vSphere client or vSphere Web client service enabled.
7.What is the difference between vSphere Client and vSphere web client ?
vSphere Client is traditional utility which provides user interface to vCenter server. But from VMware vSphere
5 onwards,vSphere web client is a primary interface to manage vCenter server.For vSphere client, you need
install small utility .But vSphere Web client doen’t require any software. You can directly connect using
web browser.But still VUM is managed through vSphere Client .
8.What is the use of VMware vCenter Orchestrator ?
vCneter Orchestrator is used for automation on various vSphere products.
9.What are the features included in VMware vSphere 5.5 ?
vSphere High Availabitliy (HA)
vSphere Fault Tolerance
vSphere vMotion
vSphere Storage vMotion
vSphere Distributed Resource Scheduler (DRS)
virtual SAN (VSAN)
Flash Read Cache
Storage I/O Control
Network I/O Control
vSphere Replication
10.What is the use of vSphere High Availability(HA)? Where it can be applied ?
VMware vSphere HA minimize the VM’s unplanned downtime by restarting the VM guests on next available
server ESXi node inacase of failure on current ESXI node. VMware HA must be enabled to reduce the VM
unplanned downtime.
Difference between ESX and ESXi
ESX 4.1 is the last version availability of ESX server. After vSphere 5, only ESXi is available.
Capability ESX ESXi
Service Console Present Removed
Troubleshooting performed via Service Console ESXi Shell
Active Director Authentication Enabled Enabled
Secure Syslog Not Supported Supported
Management Network Service Console Interface VMKernel Interface
Jumbo Frames Supported Supported
Hardware Montioring3 rd Party agents installed in
Service consoleVia CIM Providers
Boot from SAN Supported in ESX Supported in ESXi
Software patches and updatesNeeded as smilar to linux operation
systemFew pacthes because of small
footprint and more secure
vSphere web Access Only experimentalFull managenet capability via
vSPhere web client
Locked Down Mode Not presentPresent . Lockdown mode prevents
remote users to login to the host
Scripted Installtion Supported Supported
vMA Support Yes Yes
Major Administration command-line Command
esxcfg- esxcli
Rapid deployment via Auto Deploy
Not supported Supported
Custom Image creation Not supported Supported
VMkernel Network Used forvMotion,Fault Tolarance,Stoarge
Live migration of a virtual machine from one ESX server to another with Zero downtime . VMs disk files stay where they are (on shared storage)
2. What are the use cases of vMotion ?
Balance the load on ESX servers (DRS
Save power by shutting down ESX using DPM
Perform patching and maintenance on ESX server (Update Manager or HW maintenance
3. What are Pre-requisites for the vMotion to Work?
ESX host must be licensed for VMotion
ESX servers must be configured with vMotion Enabled VMkernel Ports.
ESX servers must have compatible CPU’s for the vMotion to work
ESX servers should have Shared storage (FB, iSCSI or NFS) and VM’s should be stored on that storage.
ESX servers should have exact similar network & network names
4. What are the Limitations of vMotion?
Virtual machines configured with the Raw Device Mapping(RDM) for clustering features using vMotion
VM cannot be connected to a CD-ROM or floppy drive that is using an ISO or floppy image stored on a drive that is local to the host server. The device should be disconnected before initiating the vMotion.
Virtual Machine cannot be migrated with VMotion unless the destination swapfile location is the same as the source swapfile location. As a best practice, Place the virtual machine swap files with the virtual machine configuration file.
irtual Machine affinity must not be set (aka, bound to physical CPUs).
5. Steps involved in VMWare vMotion ?
A request has been made that VM-1 should be migrated (or “VMotioned”) from ESX A to ESX B.
VM-1′s memory is pre-copied from ESX A to ESX B while ongoing changes are written to a memory bitmap on ESX A.
VM-1 is quiesced on ESX A and VM-1′s memory bitmap is copied to ESX B.
VM-1 is started on ESX B and all access to VM-1 is now directed to the copy running on ESX B.
The rest of VM-1′s memory is copied from ESX A all the while memory is being read and written from VM-1 on ESX A when applications attempt to access that memory on VM-1 on ESX B.
If the migration is successful, VM-1 is unregistered on ESX A.
1.What is SvMotion?
Migration of a virtual machine files and disks from one datastore to another with Zero downtime.
2. What are the use cases of SvMotion ?
Migrating from Old storage to new storage systems or migrating to different vendor storage without downtime to VM’s.
Performing Scheduled activity like storage upgrades on the source Lun.
Converting VM disk type from Thick to Thin and Thin to Thick.
Migrating the critical virtual machines to high performance storage arrays to improve performance of virtual Machine.
3. What are Pre-requisites for the SvMotion to Work?
ESX host in which virtual machine is running should have access to source and destination storage.
ESX host should have configured with the license for svMotion
4. What are the Limitations of SvMotion?
Virtual machines with snapshots cannot be migrated using Storage vMotion.
Virtual machine with virtual compatibility RDM can be migrated with svMotion.If you convert the mapping file, a new virtual disk is created and the contents of the mapped LUN are copied to this disk.
For Physical compatibility RDM, only mapping file can be relocated.
Virtual Machines cannot be migrated while the VMware tools installation tools is in progress.
Virtual Machine should be in powered off state if you want to migrate the VM simultaneously to different host and storage.
5. Steps involved in VMWare SvMotion ?
svMotion copies all the files expect virtual machine disk and create the directory as same the Virtual Machine name on the destination storage.
It uses Changed Block tracking to track the virtual machine disk. The change block tracking knows which region disk includes data. This data will be stored in bitmap and reside either in memory or in a file.
Pre-copies Virtual machine disk and swap file will start from the source to destination datastore as the first iteration. once it is completed, It only transfers the region which were modified or written after the first iteration.
ESX performs fast suspend and resume of the virtual Machine. The final changed regions will be copied to the destination before the virtual Machine is resumed on the destination datastore.
Virtual Machine will continue running on the destination datastore and source file and disk will be deleted.
Difference between h/w version
F e a t u r e E S X i 5 . 1 a n d l a t e r E S X i 5 . 0 a n d l a t e r E S X / E S X i 4 . x a n d
