VMware Basics Part 1

1. What is VMKernel and why it is important?

VMkernel is a virtualization interface between a Virtual Machine and the ESXi host which stores VMs. It is responsible to allocate all available resources of ESXi host to VMs such as memory, CPU, storage etc. It’s also controlled special services such as vMotion, Fault tolerance, NFS, traffic management and iSCSI. To access these services, VMkernel port can be configured on ESXi server using a standard or distributed vSwitch. Without VMkernel, hosted VMs cannot communicate with ESXi server.

2. What is the hypervisor and its types?

A hypervisor is a virtualization layer that enables multiple operating systems to share a single hardware host.  Each operating system or VM is allocated physical resources such as memory, CPU, storage etc by the host. There are two types of hypervisors

• Hosted hypervisor (works as application i-e VMware Workstation)
• Bare-metal (is virtualization software i-e VMvisor, Hyper-V which is installed directly onto the hardware and controls all physical resources).

3. What is Virtualization?

The process of creating virtual versions of physical components i-e Servers, Storage Devices, Network Devices on a physical host is called virtualization. Virtualization lets you run multiple virtual machines on a single physical machine which is called ESXi host.

4. What are the different types of virtualization?

There are 5 basic types of virtualization

• Server virtualization: consolidates the physical server and multiple OS can be run on a single server.
• Network Virtualization: Provides complete reproduction of physical network into a software-defined network.
• Storage Virtualization: Provides an abstraction layer for physical storage resources to manage and optimize in virtual deployment.
• Application Virtualization: increased mobility of applications and allows migration of VMs from a host on another with minimal downtime.
• Desktop Virtualization: virtualize desktop to reduce cost and increase service

5. What is VMware FT?

FT stands for Fault Tolerance very prominent component of VMware vSphere. It provides continuous availability for VMs when an ESXi host fails. It supports up to 4 vCPUs and 64 GB memory. FT is very bandwidth intensive and 10GB NIC is recommended to configure it. It creates a complete copy of an entire VM such as storage, compute, and memory.

6. How many vCPUs can be used for a VM in FT?

In vSphere 6.0, there can be up to 4 vCPUs and 64 GB RAM can be used.

7. What is the name of the technology used by VMware FT?

vLockstep technology is used by VMware FT

8. What is Fault Tolerant Logging?

The communication between two ESXi hosts is called FT logging when FT is configured between them. The pre-requisition of configuring FT is to configure VMKernel port.

9. Will the FT work if vCenter Server goes down?
   vCenter server is only required to enable Fault Tolerance on a VM. Once it is configured, vCenter is not required to be in online for FT to work. FT failover between primary and secondary will occur even if the vCenter is down.
10. What is the main difference between VMware HA and FT?The main difference between VMware HA and FT is: HA is enabled per cluster and VMware FT is enabled per VM. In HA, VMs will be re-started and powered-on on another host in case of a host failure, while in FT there is no downtime because the second copy will be activated in case of host failure.
11. What is virtual networking?
A network of VMs running on a physical server that is connected logically with each other is called virtual networking.
12. What is vSS?
vSS stands for Virtual Standard Switch is responsible for communication of VMs hosted on a single physical host. it works like a physical switch automatically detects a VM which want to communicate with other VM on a same physical server.
13. What is vDS?
vDS stands for Virtual Distributed Switch acts as a single switch in a whole virtual environment and is responsible to provide central provisioning, administration, and monitoring of the virtual network.
15. What are the main benefits of distributed switch (vDS)?
vDS can provide:
• Central administration for a data center
• Central provision, and
• Monitoring
16. What is VMKernal adapter and why it used?
VMKernel adapter provides network connectivity to the ESXi host to handle network traffic for vMotion, IP Storage, NAS, Fault Tolerance, and vSAN. For each type of traffic such as vMotion, vSAN etc. separate VMKernal adapter should be created and configured.
18. What are three port groups are configured in ESXi networking?
• Virtual Machine Port Group – Used for Virtual Machine Network
• Service Console Port Group – Used for Service Console Communications
• VMKernel Port Group – Used for VMotion, iSCSI, NFS Communications
19. What is VLAN and why use in virtual networking?
A logical configuration on the switch port to segment the IP Traffic where each segment cannot communicate with other segments without proper rules mentioned is called VLAN and every VLAN has a proper number called VLAN ID.
20. What is VLAN Tagging?
The practice of inserting VLAN ID into a packet header to identify which VLAN packet belongs to is called VLAN tagging.
21. What are three network security policies/modes on vSwitch?
• Promiscuous mode
• MAC address change
• Forged transmits
22. What is promiscuous mode on vSwitch?
The default mode is Reject. If Accept is selected, VM will receive all traffic port group via vSwitch.
23. What is MAC address changes network policy?
The default mode of this policy is Reject. If the Accept is selected, a host will accept requests to change the effective MAC address.
24. What is Forged transmits network policy?
The default mode is Reject. If Accept is selected, a host will not compare the source and effective MAC address transmitted from a VM.

vCenter Server

25. What are the main components of vCenter Server architecture?
There are three main components of vCenter Server architecture.
• vSphere Client and Web Client: a user interface.
• vCenter Server database: SQL server or embedded PostgreSQL to store inventory, security roles, resource pools etc.
• SSO: a security domain in a virtual environment
26. What is PSC and its components?
PSC stands for Platform Services Controller first introduced in version 6 of VMware vSphere which handles infrastructure security functions. It has three main components.
• Single Sign-On (SSO)
• VMware Certificate Authority (CA)
• Licensing service
27. What are the two main deploying methods of PSC
You can install PSC in two ways:
• Embedded
• centralized
28. What are different types of vCenter Server deployment?
It has two deployment types
• Embedded Deployment
• External deployment
29. What is vRealize Operation (vROP)
vROP provides the operation dashboards for performance analytics, capacity optimization and monitoring the virtual environment.
31. What is datastore?
Datastore is a storage location where virtual machine files are stored and accessed. Datastore is based on a file system which is called VMFS, NFS.
32. What is the .vmx file?
It is the configuration file of a VM
33. What information .nvram file stores?
It stores BIOS related information of a VM.
34. What .vmdk file does and used?
Vmdk is a VM disk file and stores data of a VM. It can be up to 62 TB in size in vSphere 6.0 version.
35. How many disk types are in VMware?
There are three disk types in vSphere.
1. Thick Provisioned Lazy Zeroes: every virtual disk is created by default in this disk format. Physical space is allocated to a VM when a virtual disk is created. It can’t be converted to thin disk.
2. Thick Provision Eager Zeroes: this disk type is used in VMware Fault Tolerance. All required disk space is allocated to a VM at time of creation. It takes more time to create a virtual disk compare to other disk formats.
3. Thin provision: It provides an on-demand allocation of disk space to a VM. When data size grows, the size of a disk will grow. Storage capacity utilization can be up to 100% with thin provisioning.
4. What is Storage vMotion?
It is similar to traditional vMotion, in Storage vMotion, a virtual disk of a VM is moved from datastore to another. During Storage vMotion, virtual disk types think provisioning disk can be transformed to thin provisioned disk.
36. What is VM Hardware version for vSphere 6.0?
Version 11
37. What VM hardware version for vSphere 6.5?
Version 13
38. In which version of vSphere PSC was introduced?
Platform Services Controller (PSC) is introduced in vSphere 6.0.