Ephemeral Ports with VMware vCloud Director 1.5 and vSphere 5

This is something that I have been thinking about in a recent build project, where we are considering using vCDNI-Backed networks in vCloud Director. Dave Hill writes a great article on using (or not) Ephemeral Ports in vCD here:


…where the focus was on 4.0 vs. 4.1 deployments.

With the recent release of vSphere 5, the arguments for and against using Ephemeral ports in a capacity context come into sharper focus:

  • vSphere 4.1: 1,016 PortGroups per vDS/vCenter
  • vSphere 5: 256 PortGroups per vDS/vCenter


So, what are the choices? In vSphere, there are 3 port binding types:
  • Static – dvPort is immediately assigned, and freed when the VM is removed. Only available for connection through vCenter. Default in vCloud Director 1.5.
  • Dynamic – dvPort is assigned when VM is powered-on and NIC connected, and freed when VM is powered-off. Not available in vSphere 5. Good for environments where there are more VMs than port groups available. VMs must be powered-on and off through vCenter.
  • Ephemeral – dvPort is created and assigned when VM is powered-on, and deleted when the VM is powered-off orNIC is disconnected. Can be created directly on ESXi hosts. Should only be used for recovery where provisioning dvPorts is required directly on hosts.
Another reason not to use Ephemeral Ports is the performance aspect. With Ephemeral ports, as these are dynamically created and destroyed, operations will be comparably slower for add-host and VM tasks than with tasks that use the Static binding type.

Jeremy loves all things technology! Has been in IT for years, loves Macs (but doesn't preach to others about their virtues), loves virtualization (and does shout about it's virtues), and sometimes skis, bikes and directs amateur plays!


  1. says

    Hi Jeremy,

    You should maybe make this statement more clear.

    Now on vCloud 1.5 we don’t use ephemeral ports anymore but static.
    Maybe put it in the bold part (“Default in vCloud Director 1.5”), instead of Default and recommended.

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