Cray System Management Documentation > Cray System Management Install > Create NCN Metadata CSV

Create NCN Metadata CSV

The information in the ncn_metadata.csv file identifies each of the management nodes, assigns the function as a master, worker, or storage node, and provides the MAC address information needed to identify the BMC and the NIC which will be used to boot the node.

Some of the data in the ncn_metadata.csv can be found in the SHCD in the HMN tab. However, the hardest data to collect is the MAC addresses for the node’s BMC, the node’s bootable network interface, and the pair of network interfaces which will become the bonded interface bond0.

Introduction

Each of the management nodes is represented as a row in the ncn_metadata.csv file.

For example:

Xname,Role,Subrole,BMC MAC,Bootstrap MAC,Bond0 MAC0,Bond0 MAC1
x3000c0s9b0n0,Management,Storage,94:40:c9:37:77:26,14:02:ec:d9:76:88,14:02:ec:d9:76:88,94:40:c9:5f:b6:92

For each management node, the component name (xname), role, and subrole can be extracted from the SHCD in the HMN tab. However, the rest of the MAC address information needs to be collected another way.

Check the description for component names while mapping names between the SHCD and the ncn_metadata.csv file. See Component Names (xnames).

There are two interesting parts to the NCN metadata file:

The MAC address of the BMC
The MAC addresses of the Shasta management network interfaces

The “Shasta management network interfaces” are the interfaces that comprise the NCNs’ LACP link-aggregation ports.

LACP bonding

NCNs may have one or more bond interfaces, which may be comprised from one or more physical interfaces. The preferred default configuration is two physical network interfaces per bond. The number of bonds themselves depends on the systems network topology.

For example, systems with 4 network interfaces on a given node could configure either of these permutations (for redundancy minimums within Shasta cluster):

One bond with 4 interfaces (bond0)
Two bonds with 2 interfaces each (bond0 and bond1)

For more information, see NCN Networking.

PXE or bootstrap MAC address

In general this refers to the interface to be used when the node attempts to PXE boot. This varies between vintages of systems; systems before Spring 2020 often booted NCNs with onboard NICs, while newer systems boot over PCIe cards.

If the system is booting over PCIe, then the Bootstrap MAC and the Bond0 MAC0 will be identical. If the system is booting over onboard NICs, then the Bootstrap MAC and the Bond0 MAC0 will be different.

Other nomenclature

Bond MAC addresses are the MAC addresses for the physical interfaces that the node will use for the various VLANs.
Bond0 MAC0 and Bond0 MAC1 should not be on the same physical network card, in order to establish redundancy for failed chips.
On the other hand, if any node’s capacity prevents it from being redundant, then MAC1 and MAC0 will still produce a valid configuration if they do reside on the same physical chip/card.
The BMC MAC is the exclusive, dedicated LAN for the onboard BMC. It should not be swapped with any other device.

Sample `ncn_metadata.csv`

The following are sample rows from a ncn_metadata.csv file:

Use case: NCN with a single dual-port PCIe card (one card with two ports):

Notice how the MAC addresses for Bond0 MAC0 and Bond0 MAC1 are only off by one, which indicates that they are on the same dual-port card.
```
Xname,Role,Subrole,BMC MAC,Bootstrap MAC,Bond0 MAC0,Bond0 MAC1
x3000c0s6b0n0,Management,Worker,94:40:c9:37:77:b8,14:02:ec:da:bb:00,14:02:ec:da:bb:00,14:02:ec:da:bb:01
```
Use case: NCN with two dual-port PCIe cards (four ports total):

Notice how the MAC addresses for Bond0 MAC0 and Bond0 MAC1 have a difference greater than one, which indicates that they are on not on the same dual-port card.
```
Xname,Role,Subrole,BMC MAC,Bootstrap MAC,Bond0 MAC0,Bond0 MAC1
x3000c0s9b0n0,Management,Storage,94:40:c9:37:77:26,14:02:ec:d9:76:88,14:02:ec:d9:76:88,94:40:c9:5f:b6:92
```

Example ncn_metadata.csv file for a system that has been configured as follows:

Management NCNs are configured to boot over the PCIe NICs
Master and storage management NCNs have two dual port PCIe cards
Worker management NCNs have one dual port PCIe card

IMPORTANT Mind the index for each group of nodes (3, 2, 1…. ; not 1, 2, 3). If storage nodes are ncn-s001 x3000c0s7b0n0, ncn-s002 x3000c0s8b0n0, ncn-s003 x3000c0s9b0n0, then their portion of the file would be ordered x3000c0s9b0n0, x3000c0s8b0n0, x3000c0s7b0n0.

Because the NCNs have been configured to boot over their PCIe NICs, the Bootstrap MAC and Bond0 MAC0 columns have the same value.

Xname,Role,Subrole,BMC MAC,Bootstrap MAC,Bond0 MAC0,Bond0 MAC1
x3000c0s9b0n0,Management,Storage,94:40:c9:37:77:26,14:02:ec:d9:76:88,14:02:ec:d9:76:88,94:40:c9:5f:b6:92
x3000c0s8b0n0,Management,Storage,94:40:c9:37:87:5a,14:02:ec:d9:7b:c8,14:02:ec:d9:7b:c8,94:40:c9:5f:b6:5c
x3000c0s7b0n0,Management,Storage,94:40:c9:37:0a:2a,14:02:ec:d9:7c:88,14:02:ec:d9:7c:88,94:40:c9:5f:9a:a8
x3000c0s6b0n0,Management,Worker,94:40:c9:37:77:b8,14:02:ec:da:bb:00,14:02:ec:da:bb:00,14:02:ec:da:bb:01
x3000c0s5b0n0,Management,Worker,94:40:c9:35:03:06,14:02:ec:d9:76:b8,14:02:ec:d9:76:b8,14:02:ec:d9:76:b9
x3000c0s4b0n0,Management,Worker,94:40:c9:37:67:60,14:02:ec:d9:7c:40,14:02:ec:d9:7c:40,14:02:ec:d9:7c:41
x3000c0s3b0n0,Management,Master,94:40:c9:37:04:84,14:02:ec:d9:79:e8,14:02:ec:d9:79:e8,94:40:c9:5f:b5:cc
x3000c0s2b0n0,Management,Master,94:40:c9:37:f9:b4,14:02:ec:da:b8:18,14:02:ec:da:b8:18,94:40:c9:5f:a3:a8
x3000c0s1b0n0,Management,Master,94:40:c9:37:87:32,14:02:ec:da:b9:98,14:02:ec:da:b9:98,14:02:ec:da:b9:99

Collection of MAC addresses

See Collect MAC Addresses for NCNs.