VMware vSphere

VMware vSphere


OpenStack Compute supports the VMware vSphere product family and enables access to advanced features such as vMotion, High Availability, and Dynamic Resource Scheduling (DRS).

This section describes how to configure VMware-based virtual machine images for launch. The VMware driver supports vCenter version 5.5.0 and later.

The VMware vCenter driver enables the nova-compute service to communicate with a VMware vCenter server that manages one or more ESX host clusters. The driver aggregates the ESX hosts in each cluster to present one large hypervisor entity for each cluster to the Compute scheduler. Because individual ESX hosts are not exposed to the scheduler, Compute schedules to the granularity of clusters and vCenter uses DRS to select the actual ESX host within the cluster. When a virtual machine makes its way into a vCenter cluster, it can use all vSphere features.

The following sections describe how to configure the VMware vCenter driver.

High-level architecture

The following diagram shows a high-level view of the VMware driver architecture:

VMware driver architecture


As the figure shows, the OpenStack Compute Scheduler sees three hypervisors that each correspond to a cluster in vCenter. nova-compute contains the VMware driver. You can run with multiple nova-compute services. It is recommended to run with one nova-compute service per ESX cluster thus ensuring that while Compute schedules at the granularity of the nova-compute service it is also in effect able to schedule at the cluster level. In turn the VMware driver inside nova-compute interacts with the vCenter APIs to select an appropriate ESX host within the cluster. Internally, vCenter uses DRS for placement.

The VMware vCenter driver also interacts with the Image service to copy VMDK images from the Image service back-end store. The dotted line in the figure represents VMDK images being copied from the OpenStack Image service to the vSphere data store. VMDK images are cached in the data store so the copy operation is only required the first time that the VMDK image is used.

After OpenStack boots a VM into a vSphere cluster, the VM becomes visible in vCenter and can access vSphere advanced features. At the same time, the VM is visible in the OpenStack dashboard and you can manage it as you would any other OpenStack VM. You can perform advanced vSphere operations in vCenter while you configure OpenStack resources such as VMs through the OpenStack dashboard.

The figure does not show how networking fits into the architecture. Both nova-network and the OpenStack Networking Service are supported. For details, see Networking with VMware vSphere.

Configuration overview

To get started with the VMware vCenter driver, complete the following high-level steps:

  1. Configure vCenter. See Prerequisites and limitations.
  2. Configure the VMware vCenter driver in the nova.conf file. See VMware vCenter driver.
  3. Load desired VMDK images into the Image service. See Images with VMware vSphere.
  4. Configure networking with either nova-network or the Networking service. See Networking with VMware vSphere.

Prerequisites and limitations

Use the following list to prepare a vSphere environment that runs with the VMware vCenter driver:

Copying VMDK files
In vSphere 5.1, copying large image files (for example, 12 GB and greater) from the Image service can take a long time. To improve performance, VMware recommends that you upgrade to VMware vCenter Server 5.1 Update 1 or later. For more information, see the Release Notes.
For any cluster that contains multiple ESX hosts, enable DRS and enable fully automated placement.
Shared storage
Only shared storage is supported and data stores must be shared among all hosts in a cluster. It is recommended to remove data stores not intended for OpenStack from clusters being configured for OpenStack.
Clusters and data stores
Do not use OpenStack clusters and data stores for other purposes. If you do, OpenStack displays incorrect usage information.
The networking configuration depends on the desired networking model. See Networking with VMware vSphere.
Security groups

If you use the VMware driver with OpenStack Networking and the NSX plug-in, security groups are supported. If you use nova-network, security groups are not supported.


The NSX plug-in is the only plug-in that is validated for vSphere.


The port range 5900 - 6105 (inclusive) is automatically enabled for VNC connections on every ESX host in all clusters under OpenStack control.


In addition to the default VNC port numbers (5900 to 6000) specified in the above document, the following ports are also used: 6101, 6102, and 6105.

You must modify the ESXi firewall configuration to allow the VNC ports. Additionally, for the firewall modifications to persist after a reboot, you must create a custom vSphere Installation Bundle (VIB) which is then installed onto the running ESXi host or added to a custom image profile used to install ESXi hosts. For details about how to create a VIB for persisting the firewall configuration modifications, see Knowledge Base.


The VIB can be downloaded from openstack-vmwareapi-team/Tools.

To use multiple vCenter installations with OpenStack, each vCenter must be assigned to a separate availability zone. This is required as the OpenStack Block Storage VMDK driver does not currently work across multiple vCenter installations.

VMware vCenter service account

OpenStack integration requires a vCenter service account with the following minimum permissions. Apply the permissions to the Datacenter root object, and select the Propagate to Child Objects option.

vCenter permissions tree
All Privileges      
    Allocate space  
    Browse datastore  
    Low level file operation  
    Remove file  
    Register extension  
    Create folder  
      Network configuration
      Storage partition configuration
    Assign network  
    Assign virtual machine to resource pool  
    Migrate powered off virtual machine  
    Migrate powered on virtual machine  
  Virtual Machine    
      Add existing disk
      Add new disk
      Add or remove device
      CPU count
      Change resource
      Disk change tracking
      Host USB device
      Modify device settings
      Raw device
      Remove disk
      Set annotation
      Swapfile placement
      Configure CD media
      Power Off
      Power On
      Create from existing
      Create new
      Clone virtual machine
      Create template from virtual machine
    Snapshot management  
      Create snapshot
      Remove snapshot
      Validate session
      View and stop sessions

VMware vCenter driver

Use the VMware vCenter driver (VMwareVCDriver) to connect OpenStack Compute with vCenter. This recommended configuration enables access through vCenter to advanced vSphere features like vMotion, High Availability, and Dynamic Resource Scheduling (DRS).

VMwareVCDriver configuration options

Add the following VMware-specific configuration options to the nova.conf file:

compute_driver = vmwareapi.VMwareVCDriver

host_ip = <vCenter hostname or IP address>
host_username = <vCenter username>
host_password = <vCenter password>
cluster_name = <vCenter cluster name>
datastore_regex = <optional datastore regex>


  • Clusters: The vCenter driver can support only a single cluster. Clusters and data stores used by the vCenter driver should not contain any VMs other than those created by the driver.
  • Data stores: The datastore_regex setting specifies the data stores to use with Compute. For example, datastore_regex="nas.*" selects all the data stores that have a name starting with “nas”. If this line is omitted, Compute uses the first data store returned by the vSphere API. It is recommended not to use this field and instead remove data stores that are not intended for OpenStack.
  • Reserved host memory: The reserved_host_memory_mb option value is 512 MB by default. However, VMware recommends that you set this option to 0 MB because the vCenter driver reports the effective memory available to the virtual machines.
  • The vCenter driver generates instance name by instance ID. Instance name template is ignored.
  • The minimum supported vCenter version is 5.5.0. Starting in the OpenStack Ocata release any version lower than 5.5.0 will be logged as a warning. In the OpenStack Pike release this will be enforced.

A nova-compute service can control one or more clusters containing multiple ESXi hosts, making nova-compute a critical service from a high availability perspective. Because the host that runs nova-compute can fail while the vCenter and ESX still run, you must protect the nova-compute service against host failures.


Many nova.conf options are relevant to libvirt but do not apply to this driver.

Images with VMware vSphere

The vCenter driver supports images in the VMDK format. Disks in this format can be obtained from VMware Fusion or from an ESX environment. It is also possible to convert other formats, such as qcow2, to the VMDK format using the qemu-img utility. After a VMDK disk is available, load it into the Image service. Then, you can use it with the VMware vCenter driver. The following sections provide additional details on the supported disks and the commands used for conversion and upload.

Supported image types

Upload images to the OpenStack Image service in VMDK format. The following VMDK disk types are supported:

  • VMFS Flat Disks (includes thin, thick, zeroedthick, and eagerzeroedthick). Note that once a VMFS thin disk is exported from VMFS to a non-VMFS location, like the OpenStack Image service, it becomes a preallocated flat disk. This impacts the transfer time from the Image service to the data store when the full preallocated flat disk, rather than the thin disk, must be transferred.
  • Monolithic Sparse disks. Sparse disks get imported from the Image service into ESXi as thin provisioned disks. Monolithic Sparse disks can be obtained from VMware Fusion or can be created by converting from other virtual disk formats using the qemu-img utility.
  • Stream-optimized disks. Stream-optimized disks are compressed sparse disks. They can be obtained from VMware vCenter/ESXi when exporting vm to ovf/ova template.

The following table shows the vmware_disktype property that applies to each of the supported VMDK disk types:

OpenStack Image service disk type settings
vmware_disktype property VMDK disk type
sparse Monolithic Sparse
thin VMFS flat, thin provisioned
preallocated (default) VMFS flat, thick/zeroedthick/eagerzeroedthick
streamOptimized Compressed Sparse

The vmware_disktype property is set when an image is loaded into the Image service. For example, the following command creates a Monolithic Sparse image by setting vmware_disktype to sparse:

$ openstack image create \
  --disk-format vmdk \
  --container-format bare \
  --property vmware_disktype="sparse" \
  --property vmware_ostype="ubuntu64Guest" \
  ubuntu-sparse < ubuntuLTS-sparse.vmdk


Specifying thin does not provide any advantage over preallocated with the current version of the driver. Future versions might restore the thin properties of the disk after it is downloaded to a vSphere data store.

The following table shows the vmware_ostype property that applies to each of the supported guest OS:


If a glance image has a vmware_ostype property which does not correspond to a valid VMware guestId, VM creation will fail, and a warning will be logged.

OpenStack Image service OS type settings
vmware_ostype property Retail Name
asianux3_64Guest Asianux Server 3 (64 bit)
asianux3Guest Asianux Server 3
asianux4_64Guest Asianux Server 4 (64 bit)
asianux4Guest Asianux Server 4
darwin64Guest Darwin 64 bit
darwinGuest Darwin
debian4_64Guest Debian GNU/Linux 4 (64 bit)
debian4Guest Debian GNU/Linux 4
debian5_64Guest Debian GNU/Linux 5 (64 bit)
debian5Guest Debian GNU/Linux 5
dosGuest MS-DOS
freebsd64Guest FreeBSD x64
freebsdGuest FreeBSD
mandrivaGuest Mandriva Linux
netware4Guest Novell NetWare 4
netware5Guest Novell NetWare 5.1
netware6Guest Novell NetWare 6.x
nld9Guest Novell Linux Desktop 9
oesGuest Open Enterprise Server
openServer5Guest SCO OpenServer 5
openServer6Guest SCO OpenServer 6
opensuse64Guest openSUSE (64 bit)
opensuseGuest openSUSE
os2Guest OS/2
other24xLinux64Guest Linux 2.4x Kernel (64 bit) (experimental)
other24xLinuxGuest Linux 2.4x Kernel
other26xLinux64Guest Linux 2.6x Kernel (64 bit) (experimental)
other26xLinuxGuest Linux 2.6x Kernel (experimental)
otherGuest Other Operating System
otherGuest64 Other Operating System (64 bit) (experimental)
otherLinux64Guest Linux (64 bit) (experimental)
otherLinuxGuest Other Linux
redhatGuest Red Hat Linux 2.1
rhel2Guest Red Hat Enterprise Linux 2
rhel3_64Guest Red Hat Enterprise Linux 3 (64 bit)
rhel3Guest Red Hat Enterprise Linux 3
rhel4_64Guest Red Hat Enterprise Linux 4 (64 bit)
rhel4Guest Red Hat Enterprise Linux 4
rhel5_64Guest Red Hat Enterprise Linux 5 (64 bit) (experimental)
rhel5Guest Red Hat Enterprise Linux 5
rhel6_64Guest Red Hat Enterprise Linux 6 (64 bit)
rhel6Guest Red Hat Enterprise Linux 6
sjdsGuest Sun Java Desktop System
sles10_64Guest SUSE Linux Enterprise Server 10 (64 bit) (experimental)
sles10Guest SUSE Linux Enterprise Server 10
sles11_64Guest SUSE Linux Enterprise Server 11 (64 bit)
sles11Guest SUSE Linux Enterprise Server 11
sles64Guest SUSE Linux Enterprise Server 9 (64 bit)
slesGuest SUSE Linux Enterprise Server 9
solaris10_64Guest Solaris 10 (64 bit) (experimental)
solaris10Guest Solaris 10 (32 bit) (experimental)
solaris6Guest Solaris 6
solaris7Guest Solaris 7
solaris8Guest Solaris 8
solaris9Guest Solaris 9
suse64Guest SUSE Linux (64 bit)
suseGuest SUSE Linux
turboLinux64Guest Turbolinux (64 bit)
turboLinuxGuest Turbolinux
ubuntu64Guest Ubuntu Linux (64 bit)
ubuntuGuest Ubuntu Linux
unixWare7Guest SCO UnixWare 7
win2000AdvServGuest Windows 2000 Advanced Server
win2000ProGuest Windows 2000 Professional
win2000ServGuest Windows 2000 Server
win31Guest Windows 3.1
win95Guest Windows 95
win98Guest Windows 98
windows7_64Guest Windows 7 (64 bit)
windows7Guest Windows 7
windows7Server64Guest Windows Server 2008 R2 (64 bit)
winLonghorn64Guest Windows Longhorn (64 bit) (experimental)
winLonghornGuest Windows Longhorn (experimental)
winMeGuest Windows Millennium Edition
winNetBusinessGuest Windows Small Business Server 2003
winNetDatacenter64Guest Windows Server 2003, Datacenter Edition (64 bit) (experimental)
winNetDatacenterGuest Windows Server 2003, Datacenter Edition
winNetEnterprise64Guest Windows Server 2003, Enterprise Edition (64 bit)
winNetEnterpriseGuest Windows Server 2003, Enterprise Edition
winNetStandard64Guest Windows Server 2003, Standard Edition (64 bit)
winNetEnterpriseGuest Windows Server 2003, Enterprise Edition
winNetStandard64Guest Windows Server 2003, Standard Edition (64 bit)
winNetStandardGuest Windows Server 2003, Standard Edition
winNetWebGuest Windows Server 2003, Web Edition
winNTGuest Windows NT 4
winVista64Guest Windows Vista (64 bit)
winVistaGuest Windows Vista
winXPHomeGuest Windows XP Home Edition
winXPPro64Guest Windows XP Professional Edition (64 bit)
winXPProGuest Windows XP Professional

Convert and load images

Using the qemu-img utility, disk images in several formats (such as, qcow2) can be converted to the VMDK format.

For example, the following command can be used to convert a qcow2 Ubuntu Trusty cloud image:

$ qemu-img convert -f qcow2 ~/Downloads/trusty-server-cloudimg-amd64-disk1.img \
  -O vmdk trusty-server-cloudimg-amd64-disk1.vmdk

VMDK disks converted through qemu-img are always monolithic sparse VMDK disks with an IDE adapter type. Using the previous example of the Ubuntu Trusty image after the qemu-img conversion, the command to upload the VMDK disk should be something like:

$ openstack image create \
  --container-format bare --disk-format vmdk \
  --property vmware_disktype="sparse" \
  --property vmware_adaptertype="ide" \
  trusty-cloud < trusty-server-cloudimg-amd64-disk1.vmdk

Note that the vmware_disktype is set to sparse and the vmware_adaptertype is set to ide in the previous command.

If the image did not come from the qemu-img utility, the vmware_disktype and vmware_adaptertype might be different. To determine the image adapter type from an image file, use the following command and look for the ddb.adapterType= line:

$ head -20 <vmdk file name>

Assuming a preallocated disk type and an iSCSI lsiLogic adapter type, the following command uploads the VMDK disk:

$ openstack image create \
  --disk-format vmdk \
  --container-format bare \
  --property vmware_adaptertype="lsiLogic" \
  --property vmware_disktype="preallocated" \
  --property vmware_ostype="ubuntu64Guest" \
  ubuntu-thick-scsi < ubuntuLTS-flat.vmdk

Currently, OS boot VMDK disks with an IDE adapter type cannot be attached to a virtual SCSI controller and likewise disks with one of the SCSI adapter types (such as, busLogic, lsiLogic, lsiLogicsas, paraVirtual) cannot be attached to the IDE controller. Therefore, as the previous examples show, it is important to set the vmware_adaptertype property correctly. The default adapter type is lsiLogic, which is SCSI, so you can omit the vmware_adaptertype property if you are certain that the image adapter type is lsiLogic.

Tag VMware images

In a mixed hypervisor environment, OpenStack Compute uses the hypervisor_type tag to match images to the correct hypervisor type. For VMware images, set the hypervisor type to vmware. Other valid hypervisor types include: hyperv, ironic, lxc, qemu, uml, and xen. Note that qemu is used for both QEMU and KVM hypervisor types.

$ openstack image create \
  --disk-format vmdk \
  --container-format bare \
  --property vmware_adaptertype="lsiLogic" \
  --property vmware_disktype="preallocated" \
  --property hypervisor_type="vmware" \
  --property vmware_ostype="ubuntu64Guest" \
  ubuntu-thick-scsi < ubuntuLTS-flat.vmdk

Optimize images

Monolithic Sparse disks are considerably faster to download but have the overhead of an additional conversion step. When imported into ESX, sparse disks get converted to VMFS flat thin provisioned disks. The download and conversion steps only affect the first launched instance that uses the sparse disk image. The converted disk image is cached, so subsequent instances that use this disk image can simply use the cached version.

To avoid the conversion step (at the cost of longer download times) consider converting sparse disks to thin provisioned or preallocated disks before loading them into the Image service.

Use one of the following tools to pre-convert sparse disks.

vSphere CLI tools

Sometimes called the remote CLI or rCLI.

Assuming that the sparse disk is made available on a data store accessible by an ESX host, the following command converts it to preallocated format:

vmkfstools --server=ip_of_some_ESX_host -i \
  /vmfs/volumes/datastore1/sparse.vmdk \

Note that the vifs tool from the same CLI package can be used to upload the disk to be converted. The vifs tool can also be used to download the converted disk if necessary.

vmkfstools directly on the ESX host

If the SSH service is enabled on an ESX host, the sparse disk can be uploaded to the ESX data store through scp and the vmkfstools local to the ESX host can use used to perform the conversion. After you log in to the host through ssh, run this command:

vmkfstools -i /vmfs/volumes/datastore1/sparse.vmdk /vmfs/volumes/datastore1/converted.vmdk

vmware-vdiskmanager is a utility that comes bundled with VMware Fusion and VMware Workstation. The following example converts a sparse disk to preallocated format:

'/Applications/VMware Fusion.app/Contents/Library/vmware-vdiskmanager' -r sparse.vmdk -t 4 converted.vmdk

In the previous cases, the converted vmdk is actually a pair of files:

  • The descriptor file converted.vmdk.
  • The actual virtual disk data file converted-flat.vmdk.

The file to be uploaded to the Image service is converted-flat.vmdk.

Image handling

The ESX hypervisor requires a copy of the VMDK file in order to boot up a virtual machine. As a result, the vCenter OpenStack Compute driver must download the VMDK via HTTP from the Image service to a data store that is visible to the hypervisor. To optimize this process, the first time a VMDK file is used, it gets cached in the data store. A cached image is stored in a folder named after the image ID. Subsequent virtual machines that need the VMDK use the cached version and don’t have to copy the file again from the Image service.

Even with a cached VMDK, there is still a copy operation from the cache location to the hypervisor file directory in the shared data store. To avoid this copy, boot the image in linked_clone mode. To learn how to enable this mode, see Configuration reference.


You can also use the img_linked_clone property (or legacy property vmware_linked_clone) in the Image service to override the linked_clone mode on a per-image basis.

If spawning a virtual machine image from ISO with a VMDK disk, the image is created and attached to the virtual machine as a blank disk. In that case img_linked_clone property for the image is just ignored.

If multiple compute nodes are running on the same host, or have a shared file system, you can enable them to use the same cache folder on the back-end data store. To configure this action, set the cache_prefix option in the nova.conf file. Its value stands for the name prefix of the folder where cached images are stored.


This can take effect only if compute nodes are running on the same host, or have a shared file system.

You can automatically purge unused images after a specified period of time. To configure this action, set these options in the DEFAULT section in the nova.conf file:

Set this option to True to specify that unused images should be removed after the duration specified in the remove_unused_original_minimum_age_seconds option. The default is True.
Specifies the duration in seconds after which an unused image is purged from the cache. The default is 86400 (24 hours).

Networking with VMware vSphere

The VMware driver supports the Networking Service through DVS and NSX. Depending on your installation,complete these configuration steps before you provision VMs:

  1. Neutron DVS Support. Before provisioning VMs, create a VDS (vNetwork Distributed Switch) with the same name as the dvs_name in nsx.ini of neutron-* services. All VM NICs are attached to this VDS. Different neutron networks will be reflected to its related port group with its own VLAN ID.

    On the network node, install the vmware-nsx plugin and configure nsx.ini as below:

host_ip = <vCenter hostname or IP address>
host_username = <vCenter username>
host_password = <vCenter password>
dvs_name = <vNetwork Distributed Switch name>
  1. Neutron NSX Support. Before provisioning VMs, install nsx manager into vSphere. For more information, see the NSX Install Guide. Install vmware-nsx plugin on neutron and configure nsx.ini on the network node. For more information, see the VMware Integrated OpenStack Documentation.

Volumes with VMware vSphere

The VMware driver supports attaching volumes from the Block Storage service. The VMware VMDK driver for OpenStack Block Storage is recommended and should be used for managing volumes based on vSphere data stores. For more information about the VMware VMDK driver, see VMware VMDK driver. Also an iSCSI volume driver provides limited support and can be used only for attachments.

Configuration reference

To customize the VMware driver, use the configuration option settings documented in Description of vmware configuration options.

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