Cisco APIC Getting Started Guide, Release 6.2(x)

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Replace a Cisco APIC in a cluster using the CLI

Updated: January 12, 2026

Overview

Learn how to replace a Cisco Application Policy Infrastructure Controller (APIC) by ensuring the replacement runs the same firmware version, decommissioning the old APIC, and commissioning the new one to maintain cluster integrity and functionality.

Before you begin

Before replacing a Cisco Application Policy Infrastructure Controller ( APIC ), ensure that the replacement Cisco APIC is running the same firmware version as the Cisco APIC to be replaced. If the versions are not the same, you must update the firmware of the replacement Cisco APIC before you begin. Initial clustering of Cisco APIC s running differing versions is an unsupported operation and may cause problems within the cluster.

  • For more information about managing clusters, see Best practices for cluster management .

  • When you replace an Cisco APIC , the password will always be synced from the cluster. When replacing APIC 1, you will be asked for a password but it will be ignored in favor of the existing password in the cluster. When replacing Cisco APIC 2 or 3, you will not be asked for a password.

Procedure

1.

Identify the Cisco APIC that you want to replace.

2.

Note the configuration details of the Cisco APIC to be replaced by using the acidiag avread command.

3.

Decommission the Cisco APIC using the decommission controller controller-id command in config mode.

Decommissioning the Cisco APIC removes the mapping between the APIC ID and Chassis ID. The new Cisco APIC typically has a different APIC ID, so you must remove this mapping in order to add a new Cisco APIC to the cluster.

Beginning with Cisco APIC release 6.0(2), an optional argument ( force ) is added to the decommission command to allow forcing the decommission operation. The revised command is decommission controller controller-id [ force ] , with the following behaviors:

  • When force is not declared, the decommission proceeds only if the cluster is not in an unhealthy or upgrade state, where a decommission may not be proper.

  • When force is declared, the decommission proceeds regardless of the cluster state.

For example, decommission controller 3 force decommissions APIC3 regardless of the cluster state.

4.

To commission the new Cisco APIC , follow these steps:

  1. Disconnect the old Cisco APIC from the fabric.

  2. Connect the replacement Cisco APIC to the fabric.

    The new Cisco APIC appears in the Cisco APIC GUI menu System > Controllers > apic_controller_name > Cluster as Seen by Node in the Unauthorized Controllers list.

  3. Commission the new Cisco APIC using the controller controller-id commission command.

  4. Boot the new Cisco APIC .

  5. Allow several minutes for the new Cisco APIC information to propagate to the rest of the cluster.

    The new Cisco APIC appears in the Cisco APIC GUI menu System > Controllers > apic_controller_name > Cluster as Seen by Node in the Active Controllers list.

What to do next

For each decommissioned controller, verify that the operational state of the controller is unregistered and that the controller is no longer in service in the cluster.

Note

If a decommissioned Cisco APIC is not promptly removed from the fabric, it might be rediscovered, which could cause problems. In that case, follow the instructions in Cluster size reductions to remove the controller.