We often ignore the basics and never really understand the whole spectrum of the SDDC (Software Defined Datacenter) product suite. Well my friend join me on exploring back to basics 101 on VMware Virtualisation. This post covers definitions and visual representations of most components of the SDDC stack.
What is virtualization?
Virtualization is an abstraction layer that breaks the hard connection between the physical hardware and the operating system. A virtual infrastructure is an enterprise-wide solution that provides fluid, powerful computing that maximizes resource utilization and cost savings. Virtual machines are the key element to a virtual infrastructure. Virtualization allows you to run multiple virtual machines with heterogeneous operating systems and applications to run in isolation, side-by-side on the same physical machine.
Physical vs. virtual
A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. It has its own set of virtual hardware on which a guest operating system and its applications run. The operating system sees a consistent set of hardware regardless of the actual physical hardware components.
Virtual machines are not emulators or simulators. They are real machines that can do the same things physical computers can do and more. Because of the flexibility of virtual machines, physical computers become less a way to provide services (applications, databases, and so on) and more a way to house the virtual machines that provide those services.
What is vCenter Server?
VMware vCenter server is a centralized management application that lets you manage virtual machines and ESXi hosts centrally. vCenter server is compulsory for enterprises to have enterprise features like vMotion, VMware High Availability, VMware Update Manager and VMware Distributed Resource Scheduler (DRS). For example, you can easily clone existing virtual machine in vCenter server.
What is a datacenter?
A datacenter is the primary container of inventory objects such as hosts and virtual machines. From the datacenter, you can add and organize inventory objects. Typically, you add hosts, folders, and clusters to a datacenter. vCenter Server can contain multiple datacenters. Large companies might use multiple datacenters to represent organizational units in their enterprise.
What is a cluster?
A cluster is a group of hosts that share resources and a management interface. When you add a host to a cluster, the host’s resources become part of the cluster’s resources. The cluster manages the resources of all hosts within it. Clusters enable the vSphere Distributed Resource Scheduler (DRS) and vSphere High Availability (HA) solutions. vSphere DRS continuously balances virtual machine workloads across your ESX/ESXi hosts. vSphere HA allows the virtual machines running on ESX/ESXi hosts to automatically recover from host failures.
What is a folder?
A folder is a container used to further refine object grouping within your inventory. Folders provide a natural structure on which to apply permissions. For example, using folders, you can organize virtual machines and templates based on function. Similarly, you can use folders to group datacenters by geographic location.
What is a datastore?
A datastore is a logical container that holds virtual machine files and other files necessary for virtual machine operations. Datastores can exist on different types of physical storage, including local storage, iSCSI, Fibre Channel SAN, or NFS. A datastore can be VMFS-based or NFS-based.