VMware vSphere and vCenter Introduction

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Logical view of vCenter/vSphere/ESX implementation






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Background
　　Benefits of virtual machines:

• Freedom from physical hardware constraints (various OS's running across different hardware)
  

• Backup and recovery with little or no down-time
  

• Greater resource utilization (multiple virtual machines run on same physical server and can manage resources)
  

　　

vCenter Server- manages multiple host servers that run multiple virtual machines

• Allows creation of new server virtual machines and create a library of virtual machine templates
  

• Allows migration of running VMs between host servers so that you can perform hardware maintenance with minimal downtime
  

• Allows you to balance VM workloads across hosts and manage VMs for high availability disaster recovery
  

• Single point of control for data center
  

• Runs on top of a windows server to manage VMware ESX/ESXi hosts and provide access control, performance monitoring, and configuration
  

• Unifies resources from individual hosts to be shared among VMs in the entire data center
  

• Performs all vSphere activities
  

　　

vSphere Client- interfaces with vCenter to manage virtual infrastructure

• Primary interface for creating, managing, and monitoring VMs, their resources, and their hosts.
  

• Multiple vSphere clients can connect to a vCenter Server
  

　　Inventory views- provide a view of all objects that the vCenter Server manages, such as data centers, resource pools, clusters, networks, data stores, templates, hosts, and VMs.

• Left panel in vSphere shows entire inventory
  

　　

Four inventory views:

• Hosts and Clusters- displays hierarchy of all inventory objects except templates, networks, and data stores
  

• VMs and Templates- displays list of VMs and templates
  

• Networks- displays list of networks
  

• Data stores- displays list of data stores
  

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Virtualization Terminology
　　Datacenter- primary container of inventory objects such as hosts, VMs, resource pools, and clusters. From the datacenter you can typically complete tasks such as adding hosts, folders, and clusters.

• vCenter can contain multiple datacenters
  

　　

Host- a computer that uses ESX or ESXi to provide CPU and memory resources that the VMs will use and give VMs access to storage on the networks.

　　

VM- a software computer that has the same functionality as a hardware computer. They run on hosts or clusters.

• You can use VMware Converter to convert a physical machine to a VM template
  

　　

Template- a master image of a VM that you can use to create and provision new VMs. Image typically includes an OS, applications and VM configuration that defines a full set of VM hardware. To create a template convert an existing VM to a template,
clone a VM to a template, or clone existing templates.

Inventory>Virtual Machine> Template > Convert to Template

Inventory>Virtual Machine> Template > Clone to Template

Inventory>Template>Clone

　　

Folder- a container to further refine the object within you inventory.

• Organize VMs and templates based on function.
  

• You can group: Datacenters, VMs (and templates), Computer resources (including hosts/clusters)
  

　　

Cluster- a group of hosts that share resources and a management interface. Cluster manages resources of all hosts within it.

• Clusters enable the VMware DRS (Distributed Resource Scheduler) and HA (High Availability) solutions.
  

• DRS continuously balances VM workloads across all ESX/ESXi servers in a cluster.
  

• HA allows virtual machines running on ESX/ESXi hosts to automatically recover from host failures
  

　　

Resource Pool- provides a way to divide the resources of a stand-alone host or a cluster into smaller pools. Configured with a set of CPU and memory resources that the VMs that run in the resource pool share.

• You can combine multiple physical servers into a single resource pool that aggregates CPU and memory
  

• Using resource pools you can:
  

• Allocate processor and memory resources to VMs running on the same cluster
  

• Establish minimum, maximum, and proportional resource shares for CPU and memory
  

• Modify allocations while VMs are running
  

• Enable applications to dynamically acquire more resources to accommodate peak performance
  

Inventory>Cluster>New Resource Pool

　　

Datastore- a logical container that holds VM files and other files necessary for VM operations.

• 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
  

• Create a new datastore by formatting LUNs or by mounting NFS volumes to an existing host.
  

• Use Add Storage command to create and configure a new datastore
  

• Every VM uses a virtual hard disk to store its OS, program files, and other data associated with its activities.
  

• Virtual disk files are stored on dedicated storage space on a variety of physical storage systems, including internal and external devices of a host, or networked storage, dedicated to the specific tasks of storing and protecting data.