Cisco ACI – How to Onboard a New Leaf Switch (Step-by-Step)

 

🏗️ Cisco ACI – How to Onboard a New Leaf Switch (Step-by-Step)

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✅ Prerequisites

Before onboarding a new leaf, make sure:

• ✔️ Cisco ACI fabric is already deployed and operational.
• ✔️ APIC(s) are reachable and healthy.
• ✔️ New leaf switch is physically installed in rack and powered off.
• ✔️ Supported transceivers and uplink cables are connected from leaf to at least one spine.
• ✔️ Switch firmware is compatible with APIC version.
• ✔️ Adequate APIC node license is available.

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🔧 Step-by-Step Process

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🔌 Step 1: Cable the Leaf Switch

• Connect uplinks (1 or more) from the new leaf switch to existing spine switches using supported optics.
• Ensure uplinks are connected before powering on the switch to allow ZTP (Zero Touch Provisioning) via LLDP.

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⚡ Step 2: Power On the Leaf Switch

• Power on the leaf switch.
• It will automatically boot and try to discover the fabric via LLDP (to spine) and TEP communication through spine to APIC.

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🔍 Step 3: Monitor Discovery in APIC

• Log in to APIC GUI
• Navigate to:
  Fabric → Inventory → Fabric Membership → Nodes Pending Registration
• Wait for the new leaf switch to appear here.
• You will see its Serial Number, Node Role = Leaf, and Status = Blank/ Not Registered

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📝 Step 4: Register the New Leaf

• Right-click on the serial number of the discovered leaf.
• Click "Register"
• In the registration window, enter:
• 🔢 Node ID: Unique numeric ID (e.g., 103)
• 🏷️ Node Name: Friendly name (e.g., Leaf103)
• Click Register

🌀 The APIC will push the basic config. The leaf will reboot and rejoin the fabric using the new node identity.

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⏱️ Step 5: Verify Registration

• After the leaf reboots, navigate to:
  Fabric → Inventory → Topology
• Confirm the new leaf:
• ✅ Appears with the correct Node ID and Name
• ✅ Has status "Active"
• ✅ Shows "Fully Fit" fabric membership state
• ✅ Has Green Health Score (> 90)