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Can ACI fabric runs on single spine switch


Can we make ACI fabric up with a single spine switch and after 10-15 days I want to add the second spine in the fabric. Is it possible...? If possible, please let me know the procedure...... 

2 Replies 2

Cisco Employee
Cisco Employee

My apologies, I read your question on my phone and did not read it thoroughly before responding.


You can run with 1 Spine and simply add the other Spine later. You just connect them up and it will appear in the APIC GUI for fabric registration just like your first Spine. There shouldn't be any loss of communication with the fabric.


Hi @losharm ,

Like @aleccham says - possible but NOT recommended for production

The procedure

Start by building the system with a Single Spine, but plan your device IDs in advance. (Device IDs are in the range 101-4000)

I would suggest you have a numbering plan before you start. E.g

  • 100-199 - Spine IDs
  • 200-299 - Local Leaf IDs
  • 300-399 - Remote Leaf IDs

Or if you plan to be multi-pod

  • 1100-1199 - Spine IDs for Pod1, 2100-2199 - Spine IDs for Pod2
  • 1200-1299 - Local Leaf IDs for Pod1, 2200-2299 -Local Leaf IDs for Pod2
  • 1300-1399 - Remote Leaf IDs for Pod1, 2300-2399 - Remote Leaf IDs for Pod2

Once the system is built, you can configure it happily with a single spine

  • If you are configuring any L3Outs, you'll need to set that single spine as the Route Reflector

When you deploy the second spine, it will be automatically discovered, but, just like in the initial configuration you'll have to allocate it an ID - it will not do ANYTHING until you've allocated the (planned) ID

Once the ID for the 2nd spine is set, you are done. Almost...

  • If you are configuring any L3Outs, you'll need to set that 2nd spine as a 2nd Route Reflector

Job done.

RedNectar aka Chris Welsh.
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