VMware vCenter Server Virtual Appliance (vCSA) features and benefits

The VMware vCenter Server Virtual Appliance (vCSA) provides an alternative option for organizations that chose not to run the Windows vCenter Server but still require centralised management of VMware vSphere deployments in the enterprise.

It provides exactly the same functionality as the traditional Windows vCenter Server but packaged in a Linux distribution. I know that some of my pure UNIX and LINUX customers have been asking for this for a while.

It’s been available as a technology preview since 2009 as “vCenter 2.5 on Linux” but has finally arrived with vSphere 5 to give customers’ an alternative to the Windows vCenter Server. Expect to see it available for download when vSphere 5 goes GA.

*UPDATE* vSphere5 is now GA, and the vCSA is available to download here.

I’ve been using it for a while now in the lab and have found it very easy to deploy and use. vCenter services start a lot quicker and the user experience with the VMware vSphere Client is exactly the same.

vCenter Server Virtual Appliance features and benefits

• Installed on SUSE Linux Enterprise Server 11 x64.
• OVF when deployed is configured with 2vCPUs and 8Gb memory, LSI Logic Parallel, VMXNET 3, 15Gb and 60Gb VMDKs and VMware Tools.
• Includes embedded DB2 database that is suitable for evaluation or for environments with less than 5 ESXi hosts or 50 virtual machines (equivalent to Windows vCenter Server + MSSQL Express).
• Supports external Oracle database for large environments.
• Includes Active Directory (AD) and Network Information Services (NIS) authentication.
• vSphere Web Client support is built into the vCenter Server Virtual Appliance. vSphere Web Client is OS agnostic and the interface is highly customisable.
• Windows vSphere Client is still supported.
• Includes a pre-configured Auto Deploy server therefore reducing operational costs with the installation of Auto Deploy.
• Can use NFS mounts to store vCenter Server Virtual Appliance core and log files.
• vCSA can act as a syslog server for ESXi system logs.
• Can be used as a network collector for ESXi kernel core dumps.
• Simplified and rapid deployment, approximately 15 minutes deployment time.
• Lower TCO by eliminating Windows OS dependency and licenses.
• Reduces operational costs – vCSA is easier to upgrade – just deploy a new appliance and connect to the external Oracle database or
• Import configuration data from previous installation.
• Patches can be installed using the vCSA web interface.

Not yet feature parity with Windows vCenter Server

vCenter Server Virtual Appliance provides all features as the Windows vCenter Server but does not support the following features:

• Microsoft SQL as the database for vCenter.
• vCenter Server Linked Mode.
• vCenter Server Heartbeat.
• IPv6.

What is Vmotion...

VMotion allows live migration of virtual machines which are running on one physical server to another such that you dont have any downtime with continuous service availability.

Benifits Of VMotion

It improve availability by conducting maintenance without disrupting business operations Moves virtual machines within server resource pools to continuously align the allocation of resources to business priorities

VMware VMotion allows users to the following tasks...

• Perform hardware maintenance without scheduled downtime.
• Proactively migrate virtual machines away from failing or underperforming servers.
• Automatically optimize and allocate entire pools of resources for optimal hardware utilization and alignment with business priorities.

How Does VMware VMotion Work?

Live migration of a virtual machine or Vmotion of a VM from one physical server to another with VMotion is described below:

Step 1:
The entire state of a virtual machine is encapsulated by set of files stored on shared storage such as Fibre Channel or iSCSI Storage Area Network (SAN) or Network Attached Storage (NAS). VMware vStorage VMFS allows multiple installations of VMware ESXi to access the same virtual machine files concurrently.

Step 2:
The active memory and precise execution state of the virtual machine is rapidly transferred over a high speed network, allowing the virtual machine to instantaneously switch from running on the source ESXi host to the destination ESXi host.

VMotion keeps the transfer period imperceptible to users by keeping track of on-going memory transactions in a bitmap.

Once the entire memory and system state has been copied over to the target ESXi host, VMotion suspends the source virtual machine, copies the bitmap to the target ESXi host, and resumes the  virtual machine on the target ESXi host.

Step 3:
The networks being used by the virtual machine are also virtualized by the underlying ESXi host, ensuring that even after the migration, the virtual machine network identity and network connections are preserved. VMotion manages the virtual MAC address as part of the process.

Once the destination machine is activated, VMotion pings the network router to ensure that it is aware of the new physical location of the virtual MAC address.

Since the migration of a virtual machine with VMotion preserves the precise execution state, the network identity, and the active network connections, the result is zero downtime and no disruption to users.