VMware Interview Questions ESX..

What is VMHA?
Minimize Downtime from Server and Operating System Failures
Key features of VMware HA include:
1) Proactive monitoring of all physical  and virtual machines 2) Automatic detection of server failure 3) Optimal placement of virtual machines after server failure 4) Scalable availability up to 32 nodes across multiple servers
What is VMware DRS (Distributed Resource Scheduler) ?
It is an utility that balances computing workloads with available resources.
features of VMware DRS
1)Continuous monitoring of hardware utilization 2) Downtime-free server maintenance
3) Centralized control of hardware parameters
DRS Configuration Steps:
Manual: vCenter will suggest migration recommendations for VM'sPartially Automated: VM's will be automatically placed onto hosts at power on and vCenter will  suggest migration recommendations Fully Automated:  VM's will be automatically placed onto hosts at power on and will be automatically migrated to attain best use of resources.
What is vMotion?

Move running virtual machines from one physical server to another with no impact to end users

What is SVmotion?
Storage VMotion relocates virtual machine disk files from one shared storage location to another shared storage location with zero downtime.

Required ports for VMware?
902/903 - vSphere Client to display virtual machine consoles./ communication between VI client and ESX server.
8080 –vCenter Management Webservices HTTP,8000 - ESX during vMotion
60099 - Used to stream inventory object changes to SDK clients
80, 443 - communication between VI client and virtual Center & web access client  
SSL port of the local instance for Vcenter Linked mode - 636
 ISCSI 3260, NFS - 2049 , Update manager SOAP - 8086, update manager web port - 9084
vmware converter SOAP port - 9085
What are port Groups?
vSwitches can be subdivided into smaller units called port groups
1. Virtual Machine
2. Service Console
3. VMKernel (for vMotion, VMware FT logging and IP storage)
what is VMKernal?
It provides basic operating system services needed to support virtualization: hardware abstraction, hardware drivers, scheduler, memory allocator, filesystem (vmfs), and virtual machine monitor (vmm)
What is Thin and Thick disks.
thick disk pre-allocates all of the space specified during the creation of thedisk
Thin disk eliminates storage waste and the need for dedicated capacity.
what is vmdk?

Virtual machine disk is a file format used by VMware products. to store a virtual machine image and the contents of a VMware virtual machine hard disk.
What are the 10 major differences between VMware ESX Server and ESXi Server?
1. VMware ESXi Server has no service console VMware
2. ESXi Server uses RCLI (Remote command line interface) instead of service console utilities
3. VMware ESXi Server is extremely thin  = fast installation + faster boot
4. VMware ESXi Server can be purchased as an embedded hypervisor on hardware
5. ESXi is so small that it can be easily installed and can even be booted from a USB Flash disk
6. VMware ESXi Server’s service console (firewall) is configured differently
7. VMware ESXi Server has a “yellow firmware console”
8. VMware ESXi Server has server health status built in
9. Some networking features are configured through the service console are not available or are experimental 10. VMware ESXi Server requires fewer patches and less rebooting
11. You can buy VMware ESXi Server for as little as $495 where esx foundation is $1500
How to upgrade ESX 3.5 to 4.0 through GUI
Login to vsphere client and put the esx in maintenance mode.
next run the vmware host update utility - > click on add host -> and click on update host and select iso image of ESX file and click next - > enter root password - > click finish.
How to upgrade ESX 3.5 to 4.0 through Command mode.
put the ESX server in maintenance mode 
vimsh -n -e /hostsvc/maintenance_mode_enter
This command upgrades an ESX 3.x host by using the ESX 4.x installation DVD:

# ./esxupgrade.sh /vmfs/volumes/storage1



To upgrade the host by using the ESX 4.x DVD
Run this command: 
# .//esxupgrade.sh
where:
is the full path to the esxupgrade.sh script.
is the VMFS datastore for the ESX 4.x service console VMDK.


1) Upgrade to ESX 4.0 using vSphere Host Update Utility which was part of vSphere Client 4.0 using the ESX 4.0 install ISO.

2) Use esxupdate/vihostupdate to upgrade to ESX 4.1 using the "pre-upgrade-from-ESX4.0-to-4.1.0-0.0.260247-release.zip" and "upgrade-from-ESX4.0-to-4.1.0-0.0.260247-release.zip" bundles.
upload these two bundles in ESX datastore and run the bundle from command mode using command esxupdate --bundle=(upgrade bundle path) update.

vSphere 5 features?

http://www.virtualizationadmin.com/articles-tutorials/vmware-esx-and-vsphere-articles/general/5-features-vsphere-5-that-you-should-care-about.html

Explain steps to install ESX server?

1. When booting from the DVD you will be presented with the ESX 4.0 installation menu

2. Select “Install ESX in graphical mode” , The installer begins

3. The End User License Agreement appears. Click the “I accept the terms of the license agreement” and click Next.
4. Select your desired keyboard layout. We’ll be using U.S. English. Click Next.

5. Do you need to install any custom drivers such as NICS, HBA’s, etc then select yes and click Next. We won’t be installing any custom drivers. Click Next.

6. Drivers have now been loaded and you’re ready for the next step. Click Next.

7. You have the option to enter in the serial number for your ESX host now or later. As we’ll be connecting this server to vCenter, we’ll select to add it later so that we can control all the licenses through one management platform. Click Next.

8. Select the network adapter that will be used to connect to the Service Console

9. You can assign an IP address to your ESX host automatically or statically. DHCP is not recommended.

10. Standard setup will get you up and running quickly with all the defaults

 11. Give a name for the local datastore. By default it is Storage1. Click Next

12.  The below screen shows the default partitioning. We’ll be changing these in the next few screens to better optimize ESX. Click Edit

13. Select time zone

14. You can enter in an NTP server or manually select the time

15. Enter in the root password.

16. You are finally presented with an installation summary

17. Installation is now complete. Click Next

18. You are prompted to reboot to complete the installation. Click Finish to reboot
How do you create new Datastore in ESX?

1) highlight your esx server
2) go to the configuration tab
3) under hardware, highlight "storage adapters"
4) highlight vmhba0 (type Block SCSI)
5) under details, you should see all your local drives that your server would see.
6) now go to storage
7) go to "Add Storage"
8) use the wizard to select local drive. Make sure you select "free space" and not "all partition" since it will delete your ESX installation.
9) once you are done, you should now see your local space.

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

Benefits of VMFS?

• Automated Cluster File System Capability

• Optimizes VM Access

• Encapsulates the Entire VM State in a Single Directory

• Simplifies Provisioning and Administration of VMs

• Provides Distributed Infrastructure Services for Multi-ESX Servers

• Facilitates Dynamic Growth

• Intelligent Cluster Volume Management

• Enables HA with Lower Management Overhead

• Simplifies Disaster Recovery

Explain P2V steps?

1. Right-click on the ESX host  and click import machine

2. Select the source machine as physical computer and click Next, provide physical computer

     hostname and administrative credentials.

3. vConverter will connect to the physical machine and Agent will be on that system.

4. Review the disk volumes

5. choose the Disk volume and ignore the page and hibernation files.

6. You can see the destination ESX host.

7. Provide name to the VM.

8. Select the datastore and NIC’s you want to connected to the new vm.

9. Install vmware tools.

10. You will be given the option to schedule the P2V conversion

11. After you click Finish, the P2V conversion (import) will begin

What is the difference between VMware and Citrix?

vmare is used for operating system virtualization and citrix is used for apllication virtualization 

Minimum system requirements to install ESX server?

VMware ESX/ESXi 4.x only installs and run on servers with 64-bit x86 CPUs.

All AMD Opterons support 64 bit.

All Intel Xeon 5100/5300 5200/5400

2GB RAM minimum

one or more network adapters. 

SCSI Adapter, Fibre Channel Adapter, or Internal RAID Controller

What is the new features in vSphere?

In vSphere 4.0 we can add Memory and Processor along with HDD and NIC's while the machine running

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.

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.

Can I do an in place upgrade from 4.0 to 4.1?

Virtualcenter unisntalls your previously installed VC and then installs the new versión.

will I  be able to just point 4.1 to the existing SQL database server after the upgrade?

SQL database will be updated with the new data or if you want  you can reinizialize

Can you manage esx4.0 hosts with vcenter 4.1?

YES

How does HA know to restart a VM from a dropped Host

(storage lock will be removed from the metadata)

Does HA use vmotion? 

The answer is no - vm stops and restarts on ESX other host

What will VCB do for me?

Here are the benefits of VMware's VCB:

Centralize backups of VMware ESX Virtual Servers

Provide file-level backups of VMware ESX Virtual Servers and provides image level backup and also provides LAN-Free backup because the VCB server is connected to the SAN through your fibre channel adaptor

Provides

Utilizes VMware Snapshots

Basically, here is how VCB works:

1) 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

2) 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.

Commands: mountvm.exe, VCBMounter.exe, vcbVmName.exe

What is not so great about VMHA?

1)CPU on each host must be compatible (almost exactly)

2)Virtual machines that are on the host system that goes down will have to be restarted.

What is Cloning?
With clones, you can make many copies of a virtual machine from a single installation and configuration process.
What is Virtulization?

Virtualization is an architecture that allows you to run multiple OS simultaneously on a single computer

What is Resource pool?
A VMware ESX Resource pool is a pool of CPU and memory resources
What is dvSwitch
dvSwitch is being centralized in vCenter and using the concept of compliance to assign a dvSwitch to a host. you will need vSphere enterprise plus to run the Nexus 1000v