A couple of days ago one of my colleagues released an article about Ephemeral Ports. The article explains about how Ephemeral ports could be used as a “backup” when vCenter is down. The summary of the article is in my opinion the paragraph I quoted below.
If the inability to quickly provision a new VM or to reconnect a vNIC while vCenter Server is unavailable has kept you from considering a pure vDS network architecture, ephemeral port groups may be a suitable safety net. You would not even need to use ephemeral port groups for production virtual networks — simply create a few to have as backups for accessing the most critical VLANs.
This started a discussion internally as the default setting is not Ephemeral but Static. So the question that this resulted in was should we define a new standard or are the “Static” port binding just as good as Ephemeral? I believe that many people are hesitant of using a pure vDS infrastructure due to the inability to make changes to the vDS when vCenter would be unavailable. This applies to both ephemeral and static however and actually leads to another point, which we won’t discuss now, vCenter resiliency. Now, from a virtual machine perspective even if vCenter is down, and Static is used as the port bindings, the virtual machine can be powered on and off. With Static all ports are pre-defined on the host level and when a virtual machine is assigned a port it can consume it. Now the difference between Ephemeral and Static is that Ephemeral allows you to assign “new ports” to new virtual nics or virtual machines. I guess the question is how often do you make changes to the network of your virtual machines when vCenter is down and what type of changes?
Seriously, do we really want to make substantial changes to our environment when our management platform is not available? I believe we shouldn’t and I also feel that Static portgroups are the way forward, they have more or less the same level of flexibility Ephemeral have and on top of that Static offers a lot of advantages from a scaling perspective!