Vmware Interview Questions

1) What are the many different virtualization possible?
Virtualization can happen in one of the following levels
1) Server infrastructure virtualization
2) Desktop virtualization
3) Storage Virtualization
4) Networking Virtualization
5) Personal level virtualization
2) What hardware version of vmware is supported with ESXi 6.5?
With ESXi 6.5 vmware hardware version 13 is supported
3) What is so unique about latest vmware version 13?
The Vmware 13 is supported on top of ESXi 6.5. Being latest this comes with lots of interesting enhancements including:
6TB of RAM per virtual machine is allowed as opposed to 4TB ram in ESX 6 vmware hardware 11 version
HArdware 3D allowed
Upto 10 NIC’s allowed
2 IDE controllers allowed that are needed for CD/DVD drive
AHCI SATA controller 32 serial ports allowed
3 parallel ports allowed
VMXNET 10G network card allowed
4) What is the vmware kernel level with ESX6.5?
Vmware kernel level 7.1 is displayed while booting or restarting the ESXi software
5) What tool is used to configure ESX software?
Once the ESX is installed, the DCUI tool as it is popularly called the Direct Control User Interface tool is used to configure root password to secure the host, configure network management options, enable SSH etc
6) Is SSH enabled by default after installation of ESX?
No. We need to manually enable SSH using DCUI tool. By default SSH is in disabled mode
7) How do you access syslogs in ESX environment?
By making use of the DCUI tool we can interact with host locally. The colorful screen bright yellow in color offers text-based menus that has Troubleshooting options tab. From that we can pick and choose syslogs
8) If we want to configure fault tolerance in virtual machines what needs to be considered?
The fault tolerance option offers best high availability in bringing up the secondary virtual machine to assume the role of its primary with no data loss in less than 10 seconds. For this to happen the virtual machine configured in this should not have more than 4CPU’s
9) What is the use of DRS in ESX environment?
The Distributed resource scheduler DRS as it is popularly called automated the vmotion which is process of moving virtual machines from one EXS host to another. Storage DRS is the automation of storage vmotion the migration of virtual machine related storage files that are stored as directories in shared storage
10) When is SSD used in shared storage?
SSD offers very high I/O throughput making it preferred virtual machine storage solution for performance sensitive applications like heavy traffic websites, SAP systems, ERP systems etc
11) Under what circumstance do you move virtual machines among ESX hosts as a scheduled maintenance?
Whenever there is a need to upgrade ESX host the virtual machines need to be moved to different ESX host. This process is called vmotion and will happen without the end user feeling the maintenance
12) During upgrade which component needs to be upgrades first?
Say if ESX 6 needs to be upgraded to ESX 6.5, then vcenter is the component that needs to be upgraded first as vcenter does not offer backward compatibility. Also the hardware version of virtual machines supported on ESX 6 is 11 whereas in ESX 6.5 is 13. Upgrading virtual machines with ESX upgrade to match the hardware version needs to be considered
12) What is a vmware storage policy based on?
Storage policy is based on availability, capacity and performance. In vsphere client vm storage policy is created as rules that need to be or not need to be applied to specific Virtual machines (VM’s)
13) I see some .vsmn files in datastore. What are those?
These are snapshot files in datastore that are stored in a particular virtual machine folder
14) Will number of CPU’s in a virtual machine impact vmotion capabilities?
Nope. Number of CPU’s has no impact on vmotion
15) What is CPU affinity?
When we right click on virtual machine, edit settings, choose CPU arrow and expand it, there is a form field called scheduling affinity. Enter the CPU number here. Typically CPU affinity is not recommended in production environment unless this is a high intensive vm that needs exclusive CPU affinity. Check with your IT team before making a decision on this
16) What is use of Vmkernel in vMotion?
As a first step in vMotion the virtual kernel vmkernel port needed for vmotion should be created with vmotion option selected in port properties of vmkernel port settings in networking tab of ESX host. The hosts that are part of vmotion should belong to same network. This is internally used for vMotion
17) What options are available when you try to monitor vsphere DRS?
Recommendations – This provides information on venter provided recommendations. Typically while we run the DRS, if there exists an issue the information is available in recommendations page. These recommendations can be applied as well as overridden. Once the recommendations are applies, we need to re-run DRS to make sure issue is fixed, more recommendations need to be applied etc depending on issue in DRS environment. In a properly working DRS environment there may not be any recommendations and the page can be empty as well
Faults – Issues are recorded here
History – Past events can be monitored from here
CPU Utilization – DRS is a performance balancing option that can be setup and used on its own as well as in ESX cluster that has HA implementation in place. In whatever case CPU utilization needs to be spread across hosts. Say if there are two hosts, 5 virtual machines in total cpu utilization will be divided among these two hosts with one slightly higher than another
Memory utilization – Similar to CPU utilization memory resources can be tracked in DRS using this page
Network utilization – Network is a crucial element in ESX DRS and this can be monitored from here
18) What options need to be set when you try to turn on vSphere DRS?
DRS Automation – This can be manual, fully automated, partially automated. In a typical environment DRS once turned on is fully automated. Manual DRS setup happens in projects with new vmware implementations. Department managers prefer to run and utilize this on manual basis to see what issues do crop up. Once the environment is stabilized it is mostly in partially automated or fully automated DRS automation mode
Additional options – Policies are set here
Power management – This can be off,manual, automatic
Advanced options
19) Where do you find details on alarm settings after they are set?
Alarms can be created at virtual machine level, host level in addition to 33 default in-built alarms. The alarms created, triggered and more issues can be monitored from issues tab. Following options are available in issues tab:
All issues
Triggered alarms
Alarm definitions
20) What are the many different datastore configuration options in ESX environment?
vCenter helps us configure the datastores using the following options – General, device backing, connectivity and multipathing, capability sets
21) How do you determine the balance level of vSphere DRS in vcenter environment?
From the vcenter, summay page, navigate to vSphere DRS panel at the bottom of the page to determine if DRS is balanced or imbalanced. In addition to this following vSphere DRS information is available in summary page:
Migration automation level – It can be one of the following values automated, manual, partially automated
Migration threshold
Power management automation level – on (or) off
DRS recommendations – While we click Run vsphere DRS from vsphere DRS configure button page, there can be some DRS recommendations. Number of recommendations is available in this location
22) What is the use of actions in alarma?
In Vmware alarm actions specify the actions to be taken when alarm state changes. This can be one of the following actions:
Reset VM
Run a command
Send a notification email
Send a notification trap
Shutdown guest on VM
Suspend VM
23) Is alarm panel available by default in vcenter layout?
Nope. By default Alarms are not available in vcenter layout. To bring the alarms panel, click on user login name in top right corner, choose layout settings. Click on alarms to enable alarm panel
24) Which options are available by default in vcenter layout?
Recent tasks, recent ations are available by default in vcenter layout
25) What options are available in edit setting menu of virtual machines?
Following options are available as part of Edit Settings panel in virtual machines. By right clicking the virtual machines, we can choose edit settings and modify one or more of the following metrics:
CPU
Memory
Hard disk
SCSI controller
Network adapter
CD/DVD Drive
USB controller
Video card
VMCI device
SATA controller
Other device
In addition to this we can choose a new device from drop down list
26) I right click my virtual machine, choose power option. I see that Shutdown Guest OS and restart Guest OS options are grayed out. The virtual machine is up and running. Power off, suspend reset options are available. What is the reason?
The options Shutdown Guest OS, restart Guest OS grayed out inspite of virtual machines in poweron , up and running status means that the vm tools that has been installed in this virtual machine has been idle. To make use of these options, open console log into the virtual machine, perform tasks for few minutes to make sure the session is live. This will change the status of idle vm tools. At this stage these options will be available again
27) If the shutdown guest OS is grayed out what should I do?
We can power off the virtual machine (or) choose restart to restart the virtual machines. Shutdown guest OS is a graceful power off option but the above mentioned two options are equally good
28) Restart Guest OS is in gray mode. I can’t change it. What should I do?
Press the restart button that does perform the restart of virtual machine as a whole. Still we achieve the same result
29) What are the services that can be enabled in VMKernel port settings?
One or more of the following available services can be enabled while configuring VMKernel port settings:
vMotion
Provisioning
Fault Tolerance Logging
Management
vSphere Replication
vSphere Replication NFC
Virtual SAN
30) When you are tasked to configure the Virtual adapter what are all the many different settings that needs to be configured?
Following settings need to be configured as part of VMKernel creation in vsphere web client:
Port Properties – In this page TCP/IP stack is configured. In addition to this most important enabled services listing is available in this page. Depending on project we need to choose one or more of the following enabled services to make them available – vmotion, provisioning, fault tolerance logging, management, vsphere replication, vsphere replication nfc,virtual san
NIC settings
IPv4 settings – This can be statisIPv4 address wherein we specify network IP address, MAC address, choose default gateway. In case of DHCP this can be dynamic IP as well
Analyze impact page – Final validation page before we finish the creation of virtual adapter
31) What are the main options availabel in navigator pane of vsphere webclient?
The four main vsphere ruling options are available by default as part of navigator pane in vsphere webclient. This is available in left side of screen. The options are :
Hosts and clusters
VM’s and folders
Datastore
Networking
These options can be pulled from home menu tab as well
32) Try launching console when virtual machine is powered off. What happens?
An error stating that server is not available is displayed. Typical error says, A server error occured. The console could not be shown because VM machine is powered off, suspended or disconnected. Power on and connect the VM and re-launch the console to reconnect. Click the vsphere web client logs for details. this can also happen when the console was open previously, the VM was powered off in-between
33) What are the many different VM/Host rules types that can be chosen in DRS?
The VM/Host rules in virtual machine DRS can be one of the following types:
Keep virtual machines together – The chosen virtual machines are always maintained in same host
Separate virtual machines – The chosen machines are distributed in separate hosts
Virtual machines to hosts – Chosen virtual machines are tied to hosts. This is useful with resource intensive virtual machines like ERP, sAP etc
Virtual machines to virtual machines – In case of websites there are stack of vm’s that are dependent on each other and dependency need to be maintained
34) What options are available in vcenter support server summary page?
Backup – Vcenter server database which can be default postgres database, as well as custom databases like oracle sql server can be backed up onto folder, FTP location etc
Create Support bundle – This will create bundle in zipped format needed for issue investigation by vmware
Reboot – vcenter reboot
Shutdown – Shutdown vcenter
35) What is the use of lockdown mode?
Lockdown mode prevents remote users from directly logging onto hosts. The default option is disabled. There are two more options like normal,strict
36) Where do you look for resource reservations in ES cluster environment?
From the vcenter server, we can monitor the resource reservation of an ESX cluster. The information is available in cluster monitoring tab. Following resource reservations can be monitored from here
CPU
Memory
Storage
Information on total cluster capacity showing how much resource is available to cluster as whole, total reservation capacity of each and every resource, used reservation, available reservation details is available in this panel
37) What are the many different monitoring options available in websphere client while cluster configuration is in place?
Following details can be monitored in ESX cluster environment
Issues
Performance
Profile Compliance
Tasks & Events
Resource Reservation
vSphere HA
Utilization
38) From where can you schedule a patch install in ESX environment?
Each and every host in vsphere web client has an option to remediate the patch schedule. This task can be done immediately, can be scheduled as a task to be run in future. The Remediate button can be accessed from update manager
39) Can we install patches in ESX environment while virtual machines are on?
Typically we try to remediate a patch install as a shceduled task. This will fail if virtual machines are on. If we manually apply patch again all the virtual machines in the host should be off for the patch install to be success
40) What error message is displayed in update manager when an attempt is made to install patches with virtual machines in on state?
A message saying Overall compliance status – Non-compliant is displayed in update manager panel. We can click on scan for updates button to make sure the overall compliance status is a success
41) What is the main item that can be authored using vapp settings?
The start sequence of virtual machines can be configured in start order option of vapp page. This can be authored. We can specify startup operation, startup sequence delay which by default is 120ms. This value can be changed. Shutdown action can also be specified in this location
42) What details can be accessed from within vSphere HA sumamry page?
When a vSphere HA (High availability) configuration is in place, details of the same can be accessed from vSphere HA summary page:
Standby Mode
Maintenance Mode
vSphere HA agent unconfiguration failures
Virtual machines – protected mode, unprotected mode
43) What vSphere HA items can be monitored from vsphere web client page?
Following items (or) parameters can be monitored
Summary – mode the hosts are in like standby mode, maintenance mode, virtual machines in protected mode, unprotected mode
Heartbeat
Configuration issues
Datastores under APD or PDL – This option talks about all path down (or) permanent datastore loss the main condition under which failover happens in a vmware host
44) What is a slot in virtual environment terminology?
In day to day life while making use of vmware slot is used invariably. Slot refers to virtual machine and not the host
45) Is vsphere HA and DRS supplement to each other or complement to each other?
In a vmware environment, vSphere HA is used for high availability, DRS is distributed resource scheduling. As the name suggests HA is to make sure vmware systems are always up and running. DRS is related to performace in vmware environment
vSphere HA – In case of host failure failover is possible. Once the failed host comes back this is not made master again
DRS – Depending on the hosts that are part of DRS, based on affinity and non-affinity rules the virtual machines are distributed across hosts. The summary shows the state which in most cases is balanced
Now, can DRS supplement vsphere. Answer is DRS can be implemented independent of vSphere HA, vSphere HA is independent of DRS. Ideally they complement each other. In most real-time cases both are in place. If host faile vmotion of machines happens owing to vsphere. Once the failed host comes back, resources are distributed with DRS implementation
46) In which scenario the vSphere HA will never work?
When there arises a scenario wherein datastore is not accessible vSphere HA will never work. There are more reasons from vmkernel networking etc
47) I see some vmsn files in my datastore folder. What are those?
Snapshots created in virtual machines are stored as snapshot files vmsn in the datastore. Snapshots created and stores will be given a name that is reflected in these vmsn files
48) Is vmware supported in MAC?
Yes. With latest versions vmware is supported in MAC as well. It is to be noted that there are some hardware specific issues related to MAC. To address these issues more information needs to be added to vmx file
49) What is the operating system requirement for running vcenter?
In case of virtual machines windows 2008, windows 2012 OS is needed for running vcenter
In case of physical box with windows 2008 or windows 2012 OS vcenter is supported
Vcenter is supported on top of vmware virtual appliance as well
50) What is a virtual appliance?
Virtual appliance is a pre-configured virtual machine that can be used for many different purposes. One common usage is vcenter virtual appliance, veeam the latest replication software from vmware is a virtual appliance as well
51) Why do we make use of vcenter in virtualized environment?
Vcenter is the centralized management platform used to administer hosts, implement features like high availability, DRS etc. Though there are many tasks that can be accomplished directly from within esx host client a central inventory that manages and maintains all hosts is vcenter
52) My database team feels that vm tools cause performance problems. Can I remove them?
Nope. Vm tools are 100% recommended to be run in virtual machines. In best practice all the virtual machines should have vm tools in place
53) Is syslog collector in vsphere same as syslog in ESXi host?
In ESXi host while we launch DCUI tool there is an option to access system logs called syslog. This is a Linux implementation. Vmware photon OS is based on Linux only. This is different than syslog collector in vsphere
54) What is stored in vcenter database?
vCenter database acts as centralized repository storing information about hosts that are added to vcenter inventory. In addition to this real-time performacne metrics, statistics is stored in this database
55) What are templates?
Templates are owned and stored within vcenter. Templates are protected entities within vcenter. Virtual machines need to be powered off to be created as templates that are stored in vcenter. These templates are deployed to replicate these virtual machines
56) What happens to distributed virtual switches when vcenter is down?
Distributed virtual switches are owned by vcenter. Once the vcenter goes down, the vmware network remains unaffected. Changes to switches can’t be done until vcenter server is back up and running
57) What is vsphere client?
This is a new browser based tool in vmware 6.5. The traditional tool used to manage hosts is vsphere web client
58) What is vmware CEIP?
CEIP is vmware customer experience improvement program
59) What is a server template?
In an environment typically in a startup setup without any product in place, vmware templates are created after installation of operating system, installation of patches etc. This is a template with no applications installed. These templates can be easily deployed and customized using sysprep tool. These are called server templates
60) How do you choose the LUN while creating NFS datastore?
In vmware environment, while we try to create NFS datastore using vSphere web client, there is no provision to choose LUN or disks from drop-down menu. In a NFS setup this is a configuration that is taken care of by NFS file server. This is not the case while we create VMFS datastore
61) What is vswp file?
Swap files in traditional systems are stored in shared storage. Now, the swap files are stored in local SSD. The vswp file is swap file
62) What is ballooning?
Vmware tools needed on virtual machines for swap out. This is ballooning
63) What is number of cores?
Cores in virtual machines translate to number of cpu’s in real-time
64) You log into datastore of a virtual machine. What are all the files do you see there? Can you explain the significance of each one of them?
Virtual machine configuration file – .vmx file. This file as the name suggests stores the configuration information of virtual machines. In case of MAC to fix the hardware issues this file needs to be modified and additional information needs to be included herein
Virtual machine BIOS – .nvram
Virtual machine swap file – .vswp
Virtual machine suspended state file – .vmss

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