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. |
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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.
What is a datastore cluster?
A datastore cluster is a collection of datastores that share resources and a management interface. When you add a datastore to a datastore cluster, the cluster’s resources become part of the datastore cluster’s resources. You use datastore clusters to aggregate storage resources, which enables you to support resource allocation policies at the datastore cluster level. When you create a datastore cluster, you can use Storage DRS to manage storage resources. The I/O load balancing functionality available with Storage DRS is available only when all hosts connected to the datastores in the datastore cluster are running vSphere version 5 or later. |
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What is a virtual machine?
A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. An operating system installed on a virtual machine is called a guest operating system. Every virtual machine has virtual devices that provide the same functionality as physical hardware. Virtual machines get CPU and memory, video cards, access to storage, and network connectivity from the hosts they run on.
What is a template?
A template is a master image of a virtual machine that you can use to create and provision new virtual machines. This image typically includes an operating system, applications, and a virtual machine configuration that defines a full set of virtual hardware.
What is a content library? A content library is a container object in the vSphere Web Client that stores VM templates, vApp templates, and other types of files. Depending on your company needs, you can create a content library that is locally used by a single vCenter Server instance, or you can publish the library to share the templates and files with other vCenter Server instances.
What is a vSphere Distributed Switch? –
A vSphere Distributed Switch acts as a single virtual switch across all associated hosts. This allows virtual machines to maintain consistent network configuration as they migrate across hosts. Like a virtual switch, a distributed virtual switch is a network hub for virtual machines. A vSphere Distributed Switch can route traffic internally between virtual machines or link to an external network. A vSphere Distributed Switch can have multiple distributed port groups assigned to it.
What is vSphere Standard Switch architecture?
Networking with vSphere Standard Switches is driven from the host level. A vSphere Standard Switch works much like a physical switch, detecting which virtual machines are connected to each of its virtual ports and using that information to forward traffic to the correct virtual machines. One or more port groups connect to a Standard Switch and specify port configuration options such as bandwidth and VLAN tagging policies for each member port. Each virtual machine NIC can be assigned to one port group.
Benefits of virtual machines
A physical machine is hard to move, difficult to copy, and bound to a specific set of hardware. Virtual machines are easy to copy and move because they are independent of physical hardware. Also, they are easy to manage because they are isolated from other virtual machines running on the same physical hardware and insulated from physical-hardware changes.
Virtual machines enhance infrastructure by providing:
Freedom from physical hardware constraints : Virtual machines allow the operation of heterogeneous operating systems running across heterogeneous hardware.
Backup and recovery with little or no down-time : You can configure virtual machines with operating systems and applications once and then clone them many times. Backing up a virtual machine is as easy as backing up a few files. In this way, virtual machines ensure fast deployment and reliability.
Greater resource utilization : Multiple virtual machines can run on the same physical server. In addition, consolidating computing power to fewer physical computers can substantially increase power savings in your enterprise.
Credit to VMware vSphere Tutorial and the vsphere web client.
