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Persistent MAC Address in Cloud (Microsoft Azure /Amazon AWS / Google GCP / OpenStack)

  • 10/28/2015

What is a NIC? It is the network adaptor on your machine. MAC address is the physical address of the adaptor. You can consider it as fixed on your machine for this discussion. However the NIC you get on a VM in cloud is a virtualized one. If you delete a VM and create a new one you will probably get a new MAC address. Why do we need a persistent MAC address? Many licensed software rely on MAC for the licenses. If you want to move licenses from one VM to another persistent MAC address becomes very useful.

It looks like a small feature. Let’s look at a few major cloud provides to see how they deal with this.

Microsoft Azure
NIC https://azure.microsoft.com/en-us/documentation/articles/resource-groups-networking/#nic

It is not available yet. According to the post it is already planned.
https://feedback.azure.com/forums/216843-virtual-machines/suggestions/5217933-static-mac-address

Amazon AWS
It is already supported. The below statement is from the official AWS documentation.
The interface maintains its private IP addresses, Elastic IP addresses, and MAC address.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html

When did AWS start supporting this? I have no idea. From this post it was not supported yet in 3/2011 but it was supported in 2/2012.https://forums.aws.amazon.com/thread.jspa?

Please continue to read at https://paullou.com/2015/10/11/persistent-mac-address-in-cloud-microsoft-azure-amazon-aws-google-gcp-openstack/