Recovering a Broken Stack After a Downgrade from FastIron 09.0.10a or Later

Downgrading from FastIron 09.0.10a or a later release is complex and may produce unexpected results. Refer to Downgrading a Stack to a Release Prior to FastIron 09.0.10a for recommended steps before downgrading.

If a stack has broken following a downgrade from a more recent release to a FastIron 08.0.9x release, you can use the following procedure to recover the stack.

When the stack breaks on downgrade, the stack boots up without stack ports, as shown in the following example.

ICX7550-48 Router# show running-config
Current configuration: 
! 
ver 08.0.95c 
! 
stack unit 1 
  module 1 icx7550-48-port-management-module 
  module 2 icx7550-qsfp-2port-80g-module 
  priority 128 
stack unit 2 
  module 1 icx7550-48-port-management-module 
  module 2 icx7550-qsfp-2port-80g-module 
  module 3 icx7600-xgf-4port-40g-module 
stack unit 3 
  module 1 icx7550-48p-port-management-module 
  module 2 icx7550-qsfp-2port-80g-module 
  module 3 icx7600-xgf-4port-40g-module 
stack mac 4cb1.cd20.36be    

Note: Depending on the target downgrade release, the show running-config command output may show different results. In some releases, default stack-ports may be present.

Complete the following steps to recover the stack.

  1. Connect to the local console of the active controller.
  2. In privileged EXEC mode, enter the configure terminal command.
    ICX7550-48 Router# configure terminal
  3. In global configuration mode, enter the stack unit command followed by the unit ID of the active controller (1 in the following example).
    ICX7550-48 Router(config)# stack unit 1
  4. Configure the original stack-ports or stack-trunks for the active controller.
    In the following example, two stack-ports are configured.
    ICX7550-48 Router(config-unit-1)# stack-port 1/2/1
ICX7550-48 Router(config-unit-1)# stack-port 1/2/2
    Note: You do not need to update the stack-ports or stack-trunks for the other stack units. The active controller learns the connections from the members as they join the stack.
  5. Return to global configuration mode, and enter the stack enable command.
    ICX7550-48 Router(config-unit-1)# exit
ICX7550-48 Router(config)# stack enable
    As soon as stacking is enabled, the active controller attempts to form a stack. However, the original standby controller may not join the stack because it may have become a standalone unit.
  6. Use one of the following options to recover the standby controller:
    • Access the local console of the standby controller, and configure the original stack-ports or stack-trunks of the unit.
    • From the active controller, enter the stack interactive-setup command, and choose Option 3 when prompted to discover the standby unit as part of the stack.
    ICX7550-48 Router(config)# exit
ICX7550-48 Router# stack interactive-setup
You can abort stack interactive-setup at any stage by <ctrl-c>
0: quit
1: change stack unit IDs
2: discover and convert new units (no startup-config flash) to members
3: discover and convert existing/new standalone units to members
2&3 can also find new links and auto-trunk or convert chain(s) to ring.

Please type your selection: 3
Probing topology to find standalone units...
  7. Once the stack forms, enter the write memory command to save the running configuration.
Parent topic: Upgrade Considerations for Stacks