Network setup Azure Local regarding multiple machine configuration

Question

Hi again :), I have a question about the networking tab when deploying Azure Local. I'm currently trying to deploy a two-node setup. When configuring the networking part through the portal, I can choose my netintents etc. (see the attachment).

I choose to seperate my management and compute traffic from my storage traffic but I was wondering how this worked. Because in the portal I can only select the netadapters from one of my nodes (this node will probably be the seed node I guess). How will this be configured on my other node? Will there be a scan for local netintents on the other node or something? Or maybe a connectivity test?

Greetings, Jaco

Answer 1

Hi Jaco,

When setting up an Azure Local (Azure Stack HCI) cluster with multiple nodes, such as a two-node configuration, you may find it confusing how networking is managed on the second node, especially since the Azure portal only allows you to select network adapters (NICs) for the primary seed node. This behavior is a result of the underlying automation framework known as Network ATC (Automated Traffic Control).

Network ATC facilitates the definition of networking intents, which are logical groupings of traffic types like management, compute, storage, and live migration, at the cluster level rather than on an individual node basis. When you specify an intent, such as separating management and compute traffic from storage traffic and assign it to specific NICs on the seed node during deployment, this configuration is saved as a cluster-wide policy. Once the cluster is fully established, Network ATC automatically applies this configuration to all other nodes within the cluster.

The application of this configuration is systematic rather than arbitrary. Network ATC conducts a NIC matching process to identify which NICs on the second node correspond to those selected on the seed node. It utilizes various parameters, including adapter names, port numbers, link speeds, PCI slot locations, and, when available, LLDP/CDP neighbor information. If matching NICs are identified on the other nodes, Network ATC configures them with the same VLANs, virtual switches, and other relevant settings, such as Quality of Service (QoS) and RDMA policies, ensuring a consistent network topology across the entire cluster.

Although you only assign NICs on one node during Azure Local deployment via the portal, Network ATC ensures that all other nodes are automatically scanned and configured to match that setup—provided the hardware is consistent—making the cluster networking reliable and easier to manage.

For your reference: Network ATC overview

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