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VMware Workstation is software that allows USERS to run multiple operating systems on the same HOST computer. Virtual machines are capable of running one INSTANCE of any operating system such as Microsoft, Linux, etc. 

Here are THREE reasons why VMware workstation is useful:  

• Allows the user to run more than one operating system on the same computer.
• It saves the current OS configuration as virtual machines.
• You can work across different OSs WITHOUT switching.

VCLOUD Suite is OFTEN described as an enterprise-grade cloud and management solution. It is a collection of multiple VMware components to build and provide a completely INTEGRATED cloud infrastructure, that includes VIRTUALIZATION, software-defined datacenter SERVICES, disaster recovery, application management, etc. 

With VDI (Virtual Desktop Infrastructure), USERS can host a desktop operating system (OS) on a server and ACCESS VM-based desktops remotely from different devices and locations. VDI is a type of IaaS (Infrastructure as a Service), which can be run in a private or public cloud. When VDI is USED, the end-user can access his or her desktops via a device called a THIN client. 

To connect virtual MACHINES, VMware vSphere offers two types of virtual switches. vSphere ADMINISTRATORS can control the traffic between VMware virtual machines using either TYPE of virtual switch.  

• vSphere STANDARD Switch (VSS): VSS is the default virtual switch when ESXi is installed. The switch allows VMs installed on one physical host to communicate with one another. The switch controls how a VM communicates with another VM on the same physical server, just as a physical switch would.

• vSphere DISTRIBUTED Switch (VDS): It acts as the single switch in a virtual environment and provides central provisioning, administrative, and monitoring capabilities for virtual networks. Additionally, it supports advanced networking features in VMware vSphere.

VMware snapshots allow you to quickly and easily save the state of a VM before making changes. A snapshot is taken when UPGRADING or installing software. In VMware snapshots, the current state of the virtual machine is preserved, so after testing, the machine can be quickly REVERTED to the desired state. After a specific task is completed, a snapshot should be REMOVED to IMPROVE performance. 

VMware HA is critical for us since we need uninterrupted service. Let's suppose that ONE of the ESX servers in the cluster crashes SUDDENLY for some reason. What would happen to the VIRTUAL machines running on that server? Do they CONTINUE running or are they falling? Likewise, they go down too. Thankfully, VMware HA allows you to RESTART these VM's on any other ESX server in the same cluster as soon as they fail. 

A promiscuous mode is network security, monitoring, and administration METHOD that allows any network adapter CONFIGURED on a host system to ACCESS all network data packets. You can specify it at the virtual switch or port group level in vSphere ESX/ESXi. Essentially, promiscuous mode is a method of monitoring (sniffing) network traffic. You have two options: ACCEPT or reject. ADDITIONALLY, all communication will be visible to all virtual machines if the promiscuous mode is set to accept. 

A virtual machine will not be migrated if the target host does not have enough MEMORY i.e., vMotion fails. This can be FIXED by moving the VM to another ESXi host PROVIDING GUARANTEED memory, or by reducing the virtual machine's memory reservation. 

VMWARE's VMotion technology enables you to migrate active virtual machines from one ESX-host to another without DISRUPTING service or functionality. During this process, there is ZERO downtime, constant service availability, and overall transaction integrity. vMotion technology plays a key role in creating a dynamic, automated, and self-optimizing data center and provides great FLEXIBILITY for virtual environments. Ensure that both hardware and software REQUIREMENTS are met by the cloud provider. The compatibility requirements are reduced if powered-off VMs are migrated.   

Fault Tolerance on a VM can only be enabled through the vCenter Server. FT does not REQUIRE vCenter to be online once CONFIGURED. Due to this fact, no FT failure between the primary and the secondary will occur when vCenter is down. 

• VMware vSphere: It's an enterprise-scale virtualization PLATFORM that lets you BUILD a reliable and resilient infrastructure to MEET pretty much any business need while staying within your budget. Vsphere adds important capabilities to data center infrastructure that prevent unplanned downtime and can completely eliminate maintenance and storage downtime. 
• VMware vCenter: It is a centralized platform used to manage virtual infrastructure. From a single console, you can control all your hosts and virtual MACHINES, enhancing visibility and preventing errors. Even if you are managing a large-scale environment, vCenter Server lets you optimize routine operations and daily tasks. As a result of this functionality, you are able to GET a detailed understanding of how your environment is configured.  

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. 

In VMWARE VSPHERE 7.0, up to 8 vCPUs can be used with the VMware vSphere ENTERPRISE PLUS license. 

• 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.

• VMware CLONE: It is an identical copy of a VM (called parent VM (VIRTUAL Machine), since it is the one from which you made a clone). MAC addresses and UUIDs for both cloned and parent VM, however, will be different. Any CHANGES to the cloned VM will not impact the original VM or parent VM (and vice versa).  
• VMware template: It is a golden image or a master copy of Virtual Machine that is capable of creating and provisioning virtual machines. It can later be used to make many clones. 

The Raw Device Mapping (RDM) files are contained in VMFS and act as proxies for raw physical devices. This feature ENABLES VMWARE's virtual machines (VMs) to access logical unit numbers (LUNs) directly. This eliminates the need to use the virtual machine file system (VMFS) because the LUN can be formatted USING any file system like NTFS (New Technology File System). It is generally beneficial for cluster CONFIGURATIONS including VM-to-VM, physical-to-VM, or SAN (Storage Area Network) snapshots. But it has some limitations, including the inability to map disk partitions and possibly not working with direct-attached block devices. 

The figure above shows that an RDM disk exists as an address mapping file on a VMFS VOLUME. This mapping file acts as a symbolic link between a VM's access to an RDM disk to LUNs.

• Type-1 Hypervisor: It acts as a LIGHTWEIGHT OS and RUNS directly on the host system. A BASE server OS is not required, and direct hardware access is available. Its example includes VMware ESXi, Citrix XenServer, etc. 
• Type-2 Hypervisor: It cannot run directly on the underlying host system, but can run as an application layer on a host system, similar to other computer programs. Its example includes VMware player or parallel desktop, VMware Server, etc.

Advantages of using Type-1 over Type-2 Hypervisor:

It is more secure to use type-1 hypervisors since they do not rely on the underlying OS, UNLIKE type-2 hypervisors. The type 2 server also loses some efficiency, performance, and speed due to this dependency. So, if you're under attack, a type-1 hypervisor will GIVE you better protection than a type-2 hypervisor. 

In the absence of virtualization, it would be impossible to run multiple operating systems at once, such as Windows and Linux.  Virtual machines serve mainly the PURPOSE of running multiple operating systems concurrently on a single piece of hardware. Splitting a PHYSICAL server into multiple units reduces the need to INVEST in additional units. You can also use VMs to ENABLE rapid disaster recovery and automatic backups of your DATA.