Using a Distributed Virtual Switch

A DistributedVirtualSwitch managed object is a virtual network switch that is located on a vCenter Server. A distributed virtual switch manages configuration for proxy switches (HostProxySwitch). A proxy switch is located on an ESXi host that is managed by the vCenter Server and is a member of the switch. A distributed switch also provides virtual port state management so that port state is maintained when vCenter Server operations move a virtual machine from one host to another.

A proxy switch performs network I/O to support the following network traffic and operations:

■	Network traffic between virtual machines on any hosts that are members of the distributed virtual switch.

■	Network traffic between a virtual machine that uses a distributed virtual switch and a virtual machine that uses a VMware standard virtual switch.

■	Network traffic between a virtual machine and a remote system on a physical network connected to the ESXi host.

■	vSphere system operations to support capabilities such as VMotion or High Availability.

A DistributedVirtualSwitch is the base distributed switch implementation. It supports a VMware distributed virtual switch implementation and it supports third party distributed switch implementations. The base implementation provides the following capabilities (defined in the DVSFeatureCapability object):

■	NIC teaming

■	Network I/O control

■	Network resource allocation

■	Quality of service tag support

■	User-defined resource pools

■	I/O passthrough (VMDirectPath Gen2)

A VmwareDistributedVirtualSwitch supports the following additional capabilities (defined in the DVSFeatureCapability and VMwareDVSFeatureCapability objects):

■	Backup, restore, and rollback for a VMware distributed virtual switch and its associated portgroups.

■	Maximum Transmission Unit (MTU) configuration.

■	Health check operations for NIC teaming and VLAN/MTU support.

■	Monitoring switch traffic using Internet Protocol Flow Information Export (IPFIX).

■	Link Layer Discovery Protocol (LLDP).

■	Virtual network segmentation using a Private VLAN (PVLAN).

■	VLAN-based SPAN (VSPAN) for virtual distributed port mirroring.

■	Link Aggregation Control Protocol (LACP) defined for uplink portgroups.

Distributed Virtual Switch Configuration

To use a distributed virtual switch, you create a switch and portgroups on a vCenter Server, and add hosts as members of the switch.

1	Use the Folder.CreateDVS_Task method to create a distributed virtual switch. Use a DVSConfigSpec to create a switch for a third-party implementation. Use a VMwareDVSConfigSpec to create a VMware distributed virtual switch.

2

Use the CreateDVPortgroup_Task method to create portgroups for host and virtual machine network connections and for the connection between proxy switches and physical NICs. A DistributedVirtualPortgroup specifies how virtual ports (DistributedVirtualPort) will be used. When you create a distributed virtual switch, the vCenter Server automatically creates one uplink portgroup (config.uplinkPortgroup). Uplink portgroups are distributed virtual portgroups that support the connection between proxy switches and physical NICs.

Port creation on a distributed switch is determined by the portgroup type (DVPortgroupConfigSpec.type):

■	If a portgroup is early binding (static), then DVPortgroupConfigSpec.numPorts determines the number of ports that get created when the portgroup is created. This number can be increased if DVPortgroupConfigSpec.autoExpand is true.

■	If a portgroup is ephemeral (dynamic), then numPorts is ignored and ports are created as needed.

You can also specify standalone ports that are not associated with a port group and uplink ports that are created on ESXi hosts (DVSConfigSpec.numStandalonePorts).

The DVPortgroupConfigInfo.numPorts property is the total number of ports for a distributed virtual switch. This total includes the ports generated by the static and dynamic portgroups and the standalone ports.

3	If you have created additional uplink portgroups, use the ReconfigureDvs_Task method to add the portgroup(s) to the DVSConfigSpec.uplinkPortgroup array.

4	Retrieve physical NIC device names from the host (HostSystem.config.network.pnic[].device).

5	Add host member(s) to the distributed virtual switch. To configure host members:

■	Specify hosts (DVSConfigSpec.host[]).

■	For each host, specify one or more physical NIC device names to identify the pNIC(s) for the host proxy connection to the network (DistributedVirtualSwitchHostMemberConfigSpec.backing.pnicSpec[].pnicDevice)

■	Use the DistributedVirtualSwitch.ReconfigureDvs_Task method to update the switch configuration.

When you add a host to a distributed virtual switch (DistributedVirtualSwitch.config.host), the host automatically creates a proxy switch. The proxy switch is removed automatically when the host is removed from the distributed virtual switch.

6	Connect hosts and virtual machines to the distributed virtual switch.

Host connection	Specify port or portgroup connections in the host virtual NIC spec (HostVirtualNicSpec.distributedVirtualPort or HostVirtualNicSpec.portgroup).
Virtual machine connection	Specify port or portgroup connections in the distributed virtual port backing (VirtualEthernetCardDistributedVirtualPortBackingInfo) for the virtual Ethernet cards on the virtual machine (VirtualEthernetCard.backing).

Backup, Rollback, and Query Operations

If you are using a VmwareDistributedVirtualSwitch, you can perform backup and rollback operations on the switch and its associated distributed virtual portgroups.

When you reconfigure a VMware distributed virtual switch (ReconfigureDvs_Task), the Server saves the current switch configuration before applying the configuration updates. The saved switch configuration includes portgroup configuration data. The Server uses the saved switch configuration as a checkpoint for rollback operations. You can rollback the switch or portgroup configuration to the saved configuration, or you can rollback to a backup configuration (EntityBackupConfig).

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To backup the switch and portgroup configuration, use the DistributedVirtualSwitchManager.DVSManagerExportEntity_Task method. The export method produces a EntityBackupConfig object. The backup configuration contains the switch and/or portgroups specified in the SelectionSet parameter. To backup the complete configuration you must select the distributed virtual switch and all of its portgroups.

■	To rollback the switch configuration, use the DVSRollback_Task method to determine if the switch configuration has changed. If it has changed, use the ReconfigureDvs_Task method to complete the rollback operation.

■	To rollback the portgroup configuration, use the DistributedVirtualPortgroup.DVPortgroupRollback_Task method to determine if the portgroup configuration has changed. If it has changed, use the ReconfigureDVPortgroup_Task method to complete the rollback operation.

To perform query operations on a distributed virtual switch, use the DistributedVirtualSwitchManager methods.