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Virtualization with VMWare Infrastructure 3.0

Archive for the ‘VM Management’ Category

Basic System Administration -Part 04

Posted by Preetam on March 25, 2007

If you remove users from the VirtualCenter domain, they lose permissions to all objects in the VMware Infrastructure and will not be able to log on again. Users who are currently logged on and are removed from the domain retain their Vmware Infrastructure permissions only until the next validation period (the default is every 24 hours)

Vmware doesn’t not explicitly restrict users from with same login and password from accessing and taking action within the VC.

If you rename user domain account, it becomes invalid in VC and same applies to group but before that(for groups only) you need to restart virtucal center.

Following activities can be scheduled as Tasks

  • Change the power state of a VM
  • Create a VM template
  • Move a VM with Vmotion
  • Create a VM
  • Make snapshot of VM
  • Customize VM
  • Add a Host

When you remove an object (such as a folder, datacenter, cluster, or resource pool), VirtualCenter removes all child inventory objects (such as datacenters, clusters, hosts, and virtual machines contained within the object). All the associated tasks and alarms are also removed. Assigned processor and migration licenses are returned to available status. Virtual machines that were on a managed host remain on the host, but are no longer managed by VirtualCenter.

This was the last part of the series from basic administration task,this pdf is in more details and end in 364 pages. There should be more information which be might be useful for VCP. I might add more to this series soon.


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Basic System Administration -Part 2

Posted by Preetam on March 24, 2007

When you install VMWARE Tools it installs

  1. Vmware tool service
  2. Set of Vmware device drivers
  • SVGA Display drivers

  • Vmxnet networking drivers

  • Bus Logic SCSI drivers

  • Memory control driver

  • Vmware mouse driver

  • I/O consolidate backup to quiesce I/O

  1. set of scripts that let’s you automate guest OS
  2. component that supports copying between the guest and managed host

If you don’t have vmware tools installed you don’t have option to restart or shutdown option. You will’ve to gracefully shutdown OS within VMs console. In order to upgrade VMWare tools, you need to shutdown VMs.

When you suspend VMs, a file is created with a. vmss extension is created, which contains the entire state of VMs. The remove from inventory cmd removes the VM only from VI client and not from from it’s datastore, however delete from disk removes it from datastore. Similiarly .vmtx is extension for template and remove from inventory and delete from datastores applies here as well. File with NVRAM extensions contains BIOS Settings.

In many cases, you can get past the problem by temporarily disabling acceleration in the virtual machine, but the applications stablize deselect “disable acceleration”

Choose Hyperthreading Sharing Mode from the pull-down menu. The options are:

Any – (default) The virtual CPUs of this virtual machine can freely share cores with other virtual CPUs of this or other virtual machines.

None – The virtual CPUs of this virtual machine have exclusive use of a processor core whenever they are scheduled to it. The other hyperthread of the core is halted while this virtual machine is using the core.

Internal – On a virtual machine with exactly two virtual processors, the two virtual processors are allowed to share one physical core (at the discretion ofthe ESX Server scheduler), but this virtual machine never shares a core with any other virtual machine. If this virtual machine has any other number of processors other than two, this setting is the same as the none setting.

Audio is available only for Windows XP and not for Window2000/windows 2003

If you wish to edit template, you’ll need to convert the template into VM.

Customization of guest OS is saved in xml file. Saved customization files are unique to each VirtualCenter Server and to each version of VirtualCenter due to encryption. You must recreate the customization files for each VirtualCenter Server. Also if you uninstall VirtualCenter and later do a fresh installation, the ability to decrypt passwords from the earlier installation is lost.

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Basic System Administration

Posted by Preetam on March 24, 2007

Bullet points from Basic system Administration Guide -Part01

  • The text is sent as a notice message to all active session users and to new users when they log in. The MIB definition files can be found at C:\Program Files\VMware\Vmware VirtualCenter\MIBS when the default installation directory is used.
  • You can perform migration between datacenters, the root folder is set as a default for every virtualcenter server, you can change the name but not add or remove it.
  • When you add multiple ESX servers to Virtual Center, VC will identify any naming conflicts that exist between virtual machines and alerts system administrator, who can rename virtual machines as necessary. The name can be 80 character long and may contact underscore,hypen.
  • Disconnecting managed hosts differs from removing it, when you disconnect it; virtual center monitoring activities are temporarily suspended. When you remove it, VC stops are monitoring and managing functions of that managed host. Hosts and all VMs on the host are removed from the inventory but historical data is not removed from VC database.
  • When adding or removing hosts, make sure NFS mounts are active, if NFS are unresponsive, the operation fails.
  • Systems with dual-core processor (two CPU cores in each processor) must use ESX server 2.5.2. VC licenses are issused by pairs of processor packages not by processor cores. Host can be removed from the cluster only if all of the virtual machines on it are powered off and host is placed into maintenance mode.
  • The Virtual CPUs page does not appear if the host is single-processor or the guest operating system does not support SMP (for example, NetWare and Windows NT 4.0)
  • When you map a LUN to a VMFS volume, virtual center creates a file that point to the LUN.Encapsulating disk information to the file allows VC to lock the LUN so that only one Virtual Machine can write to it.


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VCB -Backup Strategies

Posted by Preetam on March 5, 2007

There are two things when you think of backup of virtual machines

  • Application backup which is called File Level Backup
  • Entire VM backup Image Level Backup, ( which is quite easy, cause you just need to back VMDK)

File Level Backup: It is recommended that you put all your data in Non-System Disk, it brings it’s own advantages.

Backup Proxy Server is required for carrying out this task, this has been implemented especially to remove backup overheads from ESX/VM’s. This would be Windows 2003 server, with Backup software installed(for example netbackup) which has VCB plugin to carry out the task.

COMPONENTS involved in VCB back process are:

  • Hostd: On ESX Server and interacts with Virtual center
  • VM to be backup:
  • Backup Proxy server with 3rd party software installed on it.
  • VCB Framework which consists of
    • vcbMounter
    • vLUN driver
    • Integration module
      • Pre & Post-backup scripts which ties with
    • Backup application (for example Netbackup)


  • Backup application starts backup job as per pre-schedule time
  • Pre-backup script is intiated by backup software 
    • Quiesces NTFS/FAT (only in case of MS Guest OS),this ensure no write operations are pending
    • Puts VM in snapshot mode
    • Snapshot is taken and put’s VM into normal opertion
    • Backup software mounts this Snapshot for File Level Backup, and selected files are copied. (Done by Backup client)
    • For Image level back, entire disk is export to Backup proxy server.(Done by backup client)
  • Post-backup script is called
    • which unmounts VM snapshot from backup proxy
    • Takes VM out of snapshot mode, commits any changes made to the disk during the snapshot mode.

Restoring backups done using VCB approach

Restoring file/Images taken via backup is not straight forward. There are three approaches for this

  • Self-Service restore : Backup agent Installed on each and every VM
  • Per-group restore : Select VM’s which will do restore work (i.e. install backup agent only these VM’s) and then get someone to restore files of those specific VM’s
  • Centralized restore: Backup agent is installed only on Backup Proxy and restore file/Image on backup proxy. After you can uses windows share to copy data over the location

These approachs differs from each other at one level i.e. present of backup agents. Backup agents here are only doing restore work.

For Image level backup you can use VCBMounter to backup entire virtual machine in the service console. VCBMounter quiesce the snapshot of the VM and export the setfiles which can be later on used to restore using VCBRestore.  This can be done only from Service Console.For file level back you have to use third party backup software.

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VMWare -Raw Device Mapping(RDM)

Posted by Preetam on February 19, 2007

Before we discuss what is Raw Device Mapping?, we need to know why it is required, it becomes simple to answer first question.

RDM is used when

  1. You wish to Cluster VM across boxes or Physical to Virtual,In any MSCS clustering scenario that spans physical hosts — virtual-to-virtual clusters as well as physical-to-virtual clusters. In this case, cluster data and quorum disks should be configured as RDMs rather than as files on a shared VMFS.
  2. To enable use of SAN Management software inside VM’s

Let’s get to the concept of RDM

Imagine RDM as symbolic link from VMFS Volume to a raw LUN,mapping makes LUN appear as files in VMFS. It RDM not RAW LUN is referred in the virtual machine configuration. When you map a LUN to VMFS, it creates a file with extension vmdk, which points to RAW LUN.This just a file, which contains information about RAW LUN and it is locked by virtual center so that VM can write to LUN. In short it means actually data is written on the disk.

Let’s see how to map SAN LUN:

1) When you add a disk you have to option to select the whether you want to mapped SAN LUN

click next

2) Select datastore on which you would like to map SAN LUN

Press Next

3) Select a compatibility mode physical or virtual

With Physical compatibility mode you VM can access LUN directly. This is generally used from the application inside VM wants to directly access LUN. However using physical compatibility mode you loose option to clone VM,make it a template and migration when it involved moving disks.When you wish to implement MS cluster you have to select Physical Compatibility mode

With Virtual compatibility mode, you get several features, like enabling snapshots on disk. Virtual compatibility allows the LUN to behave as VMDK, which enables us to use features like cloning to template,cloning to VM or migrations.

4) Depending upon choice you selec above you would get different screens.You can select the options like virtual disk modes and etc.

Managing path of RAW LUN

It is similiar as the you manage path for Datastores

Then you set policy to manage path by selecting Manage Paths.

Just came across very pictures on how RDM looks on the whole picture, where there external storage. Grey dotted lines are RDM’s. This is screen shotted from NETapps PDF. Hope they won’t mind.


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VMware -VM Management

Posted by Preetam on February 19, 2007

You can move VM’s between ESX servers. Moving VM’s when they are power off it is called Cold Migration. So what would be Hot Migration, nothing but VMotion. We will deal with it in more details in later posts. Cold migration of VM gives you option to move the files to different datastores, but in most cases Datastores are shared and ESX shouldn’t have problem in accessing those files. In case situation where it is not possible to access these files, files are also moved along.

So when you perform Cold Migration ?

  • When you would like to move VM’ to local datastore of ESX server
  • And when VM’s are to be moved to two different CPU families
  • Or when are upgrading your ESX hosts

Adding Devices:

VM need to be Power Off for adding most of the devices, Except for Hard disk, which is called Hot Plug. In case you need to add additional NIC, you can do only when the VM is power off. In order add device, Power off VM. In the summary tab, click Edit settings, VM properties are displayed. Click on add hardware Wizard and select the device you would like to add.

Adding SCSI Device

Select Device, remember to tick Device Status 

Select Device to be mapped on VM

Summary to finish

More Information:

http://pubs.vmware.com/vi301/wwhelp/wwhimpl/js/html/wwhelp.htm and Search for add device

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