VMware Interview-Tech Interview Contributed by Shah updated on Apr 2019

                                   Vmware Interview Question and Answers


1) Explain about your production environment? How many cluster’s, ESX, Data Centers, H/w etc ?

2) How does VMotion works? What’s the port number used for it?
ANS--> TCP port 8000

3) Prerequisites for VMotion?
a)ESX Servers must be configured with VMkenerl ports enabled for vmotion and on the same network segment
b)ESX Servers must be managed by the same Virtual Center server
c)ESX Must have compatible CPUs
d)ESX Servers muct have consisten Networks and NEtwroks labels
e)The VMs must be stored on shared storage - iSCSI or FC SAN or NAS/NFS
f)The VMs can not use localcd/floppy or internal only vrtual switches on the ESX server

4) How does HA works? Port number? How many host failure allowed and why?
ANS--> Maximum allowed host failures within a HA cluster is 4. What happens if 4 hosts have failed and a 5th one also fails.
I have still enough free resources to start up the virtual machines on the remaining hosts. Will HA start these virtual machines from the 5th failed host on the remaining hosts?
ANS) That depends. If you have admission control enabled, if there are any resource constraints some VM's may not restart. If you have admission control disabled, the VM's will get restarted on any host left in the cluster. However, that doesn't mean they will be functional. Make sure you have enough port groups configured on your vSwitch for your Virtual Machine port group to accommodate

Host Firewalls. On ESX/ESXi hosts, VMware HA needs and automatically opens the following firewall ports.
Incoming port: TCP/UDP 8042-8045
Outgoing port: TCP/UDP 2050-2250

5) What are active host / primary host in HA? Explain it?
When you add a host to a VMware HA cluster, an agent is uploaded to the host and configured to communicat with other agents in the cluster. The first five hosts added to the cluster are designated as primary hosts, and all subsequent hosts are designated as secondary hosts. The primary hosts maintain and replicate all cluster state and are used to initiate failover actions. If a primary host is removed from the cluster, VMware HA promotes another host to primary status.Any host that joins the cluster must communicate with an existing primary host to complete its configuration (except when you are adding the first host to the cluster). At least one primary host must be functional for VMware HA to operate correctly. If all primary hosts are unavailable (not responding), no hosts can be successfully configured for VMware HA.

One of the primary hosts is also designated as the active primary host and its responsibilities include:
Deciding where to restart virtual machines.
Keeping track of failed restart attempts.
Determining when it is appropriate to keep trying to restart a virtual machine.
If the active primary host fails, another primary host replaces it.

6) Prerequisites for HA ?
First, for clusters enabled for VMware HA, all virtual machines and their configuration files must
reside on shared storage (Fibre Channel SAN, iSCSI SAN, or SAN iSCI NAS), because you need to
be able to power on the virtual machine on any host in the cluster.
Second, VMware HA monitors heartbeat between hosts on the console network for failure
detection. So, to have reliable failure detection for HA clusters, the console network should have
redundant network paths. That way, if a host's first network connection fails, the second
connection can broadcast heartbeats to other hosts.
Last, if you want to use DRS with HA for load balancing, the hosts in your cluster must be part of
a VMotion network. If the hosts are not in the VMotion network, however, DRS can still make
initial placement recommendations.

7) How do DRS works? Which technology used? What are the priority counts to migrate the VM’s?

8) How does snap shot’s works?


9) What are the files will be created while creating a VM and after powering on the VM?

10) If the VMDK header file corrupt what will happen? How do you troubleshoot?

11) Prerequisites VC, Update manager?

12) Have you ever patched the ESX host? What are the steps involved in that?

13) Have you ever installed an ESX host? What are the pre and post conversion steps involved in that? What would be the portions listed? What would be the max size of it?

14) I turned on Maintenance mode in an ESX host, all the VM’s has been migrated to another host, but only one VM failed to migrate? What are the possible reasons?

15) How will you turn start / stop a VM through command prompt?

16) I have upgraded a VM from 4 to 8 GB RAM; it’s getting failed at 90% of powering on? How do you troubleshoot?

17) Storage team provided the new LUN ID to you? How will you configure the LUN in VC? What would be the block size (say for 500 GB volume size)?

18) I want to add a new VLAN to the production network? What are the steps involved in that? And how do you enable it?

19) Explain about VCB? What it the minimum priority (*) to consolidate a machine?

20) How VDR works?

21) What’s the difference between Top and ESXTOP command?

22) How will you check the network bandwidth utilization in an ESXS host through command prompt?

23) How will you generate a report for list of ESX, VM’s, RAM and CPU used in your Vsphere environment?

24) What the difference between connecting the ESX host through VC and Vsphere? What are the services involved in that? What are the port numbers’s used?

25) How does FT works? Prerequisites? Port used?