VMware Interview Question :-
* Interviewer may ask , which files are created when we create a VM and what are the roles ?
Ans ) Below I have attached the screenshots of files and the roles when we create VM on ESXi host .
a) .nvram - It is a nonvolatile ram . It is permanent memory . It contains system Bios .
b) .vmdk -It is the original file . It store operating system application .
c) .vmsd -It is a meta data of snapshot . If we create snapshot the metadata of snapshot stores in vmsd .
d) .vmx - It always stores the hardware configuration of vm .
e) .vmx.lck - It is a lock file
f) .vswp - It is a swap file . Virtual memory of our system . If we install ESXi in base machine we get only 1 .vswp file as I have installed in vmware workstation and workstation is installed in base laptop for that I have 2 .vswp file .
g) vm.scroreboard - This is only available in latest 8.0 esxi host .
h) vmware.log - It create when we start the vm only .
Diffrence between Thin & Tick Disk provisioning.
Ans ) This provisioned comes under the Disk provisioning . When we create the VM this option we get . I have attached the screenshot with roles .
1- Thin provisioned - If we have provided 200 GB is provided to a VM and 25gb is used . We can use 175gb to create another VM .
2-Thick provisioned, lazily zeroed - It will consume all 200gb . It also doesn't support HA , FT and VM migration .
3- Thick provisioned, eagerly zeroed - It consumes all 200gb , but it support HA , FT and Migration .
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* What is the boot process of your ESXI host ?
* What are the components of vCenter ?
* How to reset the Root password ?
* Which is the snapshot files ?
* If your host is disconnected from vCenter, what may be the issue ?
* What is the difference between vmotion and svmotion?
*We are not able to delete snapshots, what troubleshoot we need to do ?
* VCenter login fails ? What are the troubleshoot we need to do .
*What are the differences between Standard switch and Distributed switch.
*Why the VMs not being migrated automatically in a DRS - enabled cluster ?
*What is cold and hot migration ?
*If .vmdk file is corrupted can we retrieve our data ?
*The VMs is stuck in a “Suspended state “ . How can we resolve this ?
1. How many port-groups that are configured in ESXi networking.
The following are the three port-groups configured in ESXi networking:
Virtual Machine Port Group: They are used for Virtual Machine Network.
Service Console Port Group: They are used for Service Console Communications.
VMKernel Port Group: They are used for vMotion, iSCSI, NFS (Network File System) Communications.
2. Explain about iSCSI storage.
Generally, iSCSI SANs consist of an iSCSI storage system, which houses one or more storage processors. Communication between the host and array occurs over TCP/IP protocol, and ESXi hosts are configured with an iSCSI initiator. Such an initiator is either hardware- or software-based. The hardware-based initiators can be dependent or independent; the software-based ones are called iSCSI software initiators.
3. What is the meaning of VVol?
vSphere 6.0 introduces the concept of Virtual Volume, also known as VVol, for managing virtual disks. Whenever a virtual disk is created in a virtual environment, VVol is automatically created. At the virtual disk level, it enables array-based operations.
4. How many CPUs can be used for a VM in FT in vSphere 7.0?
In VMware vSphere 7.0, up to 8 vCPUs can be used with the VMware vSphere Enterprise Plus license.
5. Explain FT logging traffic.
For VMware FT, fault tolerance logging traffic is considered as the second network requirement. For continuous data syncing between primary and secondary VMs, Fault Tolerance applies FT logging. Additionally, this is a VMkernel connection type used to move nondeterministic events from primary to secondary VMs.
6-. What do you mean by VMware HA and VMware FT? Difference between them.
VMware HA (High availability): It generally works on Cluster Level. By pooling VMs and the hosts they reside on into a cluster, VMware HA provides high availability for VMs. VMs running on a failed host are forced to be restarted on alternate hosts.
VMware FT (Fault Tolerance): It generally works on VM Level. In this, a secondary VM is created and maintained that is identical to the primary and can replace it when the ESXi host fails to provide continuous availability of VMs. A complete copy of a VM is made, including storage, computation, and memory. To configure FT, a 10GB NIC is recommended.
Difference between VMware HA and VMware FT-
While VMware HA is enabled per cluster, VMware FT is enabled per VM.
VMware HA works on cluster level whereas VMware FT works on VM level.
An HA system will restart and power on VMs on another host in the event of a failure, while an FT system will activate the second copy in case of a loss of the primary host. By providing fast backup and continuous availability, it reduces downtime.
1. Can you elaborate what kind of process chain optimization what is the end result ?
2. What was the optimization steps you done?
3. Select * is recommended are not ? Instead of that what should I do?
4. What is the difference b/w start routine and end routine ?
5. What if I have extra logic that I need to implement / add few records where can I do it . If I want add more records to package (target) where can that be done?
6. What kind of ADSO you created in you project ?
7. What is the difference b/w types of ADSO's
8. Have you work with native Hana calculation views?
9. What type of nodes you can see while creating and debugging in you project?
10. What is the difference b/w left outer join and right outer join.
11. What about the full outer join?
12.All of sudden ECC system got slow down what will be the impact of the systems.?
13. ECC system after 30 min working fine what are the check you perform BW end from your end?
14. Some missing documents extracting with the help of the Setup table filling what will be the check points before loading into BW ?
15. In DSO there is data from 10 years history due to change the business requirement you have to add one more key field in the DSO what will be the approach ?
16. Have you worked on the query designer ?
17. What is the difference b/w selection and structures ?
18. You created one query in Bex designer imported to production after some days user reported the query is taking lot of time what will be the approach to investigate ?
19. We have a flow from DSO to info cube we have Delta DTP which loads data from DSO to cube you don't want to disturb the existing flow there is requirement for another delta DTP create - can we create ?
20. In DTP we have error handling right what does it mean - it trigger the error handling DTP where it stores the data ?
Types of Snapshots in VMware
In VMware, there are three main types of snapshots you can take of a virtual machine (VM):
Standard Snapshot:
Description: Captures only the virtual disk state, excluding the memory state.
Use Case: Ideal for scenarios where you don't need to preserve the running state of applications or processes. It's faster to create and consumes less storage space.
Memory Snapshot:
Description: Captures both the virtual disk state and the memory state of the VM at the time of the snapshot.
Use Case: Useful when you need to preserve the exact running state of the VM, including all active processes and applications.
Quiesced Snapshot:
Description: Pauses or quiesces the VM's file system and applications before taking the snapshot to ensure data consistency.
Use Case: Essential for scenarios where data integrity is critical, such as databases or applications that require consistent states.
Each type of snapshot serves different purposes, so choosing the right one depends on your specific needs and the state you want to capture.
If you have any more questions or need further details, feel free to ask!
VMware Interview question answer by Mukesh.=Part1
1. VM is not starting due to a file lock issue. How would you resolve it?
Check which host has locked the file by using the vmkfstools -D command. Find the lock owner, and if it’s safe, terminate the process locking the file or reboot the host. If the issue persists, review the logs and remove the lock manually.
2. You notice high CPU usage on a VM. What steps would you take?
Check the performance tab in vSphere.
Analyze the guest OS for any high-consuming processes.
Adjust CPU reservation and limit settings.
Consider adding vCPUs if the demand justifies it or balance workloads across VMs.
3. VM snapshot consolidation fails. How do you fix it?
Attempt to manually consolidate snapshots through the VM’s Snapshot Manager. If it fails, look at the host and vCenter logs. Use commands like vmkfstools to consolidate from the CLI. In critical situations, consider cloning the VM and deleting the original.
4. Storage migration fails with error “Insufficient Disk Space.” What would you do?
Check the datastore’s free space.
Free up space by deleting unnecessary files, old snapshots, or using Storage vMotion to move VMs off the datastore.
Review if thin provisioning is being used and causing unexpected growth.
5. You need to upgrade VMware Tools on multiple VMs. What’s the most efficient method?
Use the VMware vSphere Update Manager (VUM) to automate VMware Tools upgrades across multiple VMs. This allows centralized management and scheduled upgrades with minimal manual effort.
6. A VM is unresponsive but powered on. How would you troubleshoot?
Attempt a graceful shutdown using vSphere.
Use the ESXi command line (e.g., esxcli vm process list) to check the VM status and terminate the process if needed.
Review the logs to identify any potential causes of the freeze.
7. A VM migration (vMotion) fails. What steps do you take?
Check if vMotion is enabled and correctly configured on both hosts.
Ensure shared storage is available.
Verify there’s no network issue or port group misconfiguration.
Look at vMotion-related logs for further diagnostics.
8. VM is consuming excessive IOPS. How do you troubleshoot?
Review the performance metrics in vSphere.
Check if the VM is overutilizing its allocated storage or there are any misconfigured applications inside the guest OS.
Implement I/O limits or QoS policies in VMware to control high storage consumption.
9. The vCenter service fails to start. How would you resolve it?
Check the vCenter logs to identify the root cause.
Verify disk space availability on the vCenter server.
Restart the vCenter services using the command service-control –start –all.
Ensure database connections are intact.
Determining Why a VM Was Powered-Off or Restarted
Reason -----------------------------------------------------------------------
Clients connected to services running in a virtual machine are no longer accessible
Applications dependent on services running in a virtual machine are reporting errors
A virtual machine no longer responds to network connections
A virtual machine no longer responds to user interaction at the console
A virtual machine has been turned off unexpectedly
A virtual machine has been rebooted unexpectedly
In the vmware.log, an error similar to this appears:
PIIX4: PM Soft Off. Good-bye
In the Windows Event Viewer, this message is seen:
User sent the guest OS shutdown
Hostd logs (hostd.log) shows below snippet:
Info hostd : State Transistion (VM_STATE_ON -> VM_STATE_SHUTTING_DOWN)
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Resolution
To determine why the virtual machine was powered off or rebooted:
Verify the location of the virtual machine log files:
Open the vSphere Client and connect to the vCenter Server.
Provide administrative credentials when prompted.
Go to the Hosts & Clusters view.
Select the virtual machine in the Inventory.
Click the Summary tab.
Click Edit Settings.
Click the Options tab.
Select General Options.
Record the Virtual Machine Working Location on the right side.
Open the virtual machine log file:
Open a browser and enter the URL http://<vCenter hostname>.
Where, <vCenter hostname> is the IP or fully qualified domain name for the vCenter Server.
Provide administrative credentials when prompted.
Click the Browse datastores in the VirtualCenter inventory link.
Navigate the webpages until the appropriate datacenter and datastore are reached, and folder as noted in step 1.
Click the link to the appropriate log file, and open it with a preferred editor.
Note: A new vmware-#.log file is created during a hard reset, power on, or vMotion of the virtual machine. Use the dates in the Last Modified column to determine the logs, which recorded the outage.
Record the name of the VMware ESXi host that was running the virtual machine when it abruptly rebooted or shut down. The second line of the vmware.log file contains an entry that identifies the host. For example:
[YYYY-MM-DDTHH:MM:SS] vmx| Hostname=esx02.example.com
Determine if the virtual machine was powered off or restarted by the guest operating system:
A Guest OS initiated reset generates this event in the virtual machine logs, i.e vmware.log
[YYYY-MM-DDTHH:MM:SS]| vcpu-0| CPU reset: soft
[YYYY-MM-DDTHH:MM:SS]| vcpu-0| Chipset: The guest has requested that the virtual machine be hard reset.
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