Replacing a standby/active CPM-IMM node with another CPM-IMM node

About this task

When replacing a node, the SD card used to boot the replacement node must contain a version of the boot.tim and both.tim images that match that of the active CPM. If the versions do not match, the bootup will not be successful.

If a VC is configured with only a single CPM-IMM node and that node fails, the entire VC is down, including the IMM-only nodes. The IMM-only nodes reboot if they do not hear from the active CPM node after some time.

If the stacking ports are not connected together to form a ring connecting all the nodes of the VC, any failure in the VC (whether a link or a node failure) will isolate some nodes off of the VC, affecting all the services on those nodes. In addition, if the uplink is through one of the nodes that has been isolated or has failed, services using the uplink for the entire VC are affected. The procedure here assumes a ring of stacking ports is configured.

In the following scenario, it is assumed that a CPM-IMM node has failed and needs to be replaced. It is assumed that a redundant CPM node is configured and another CPM-IMM node is currently active. The replacement node might be a new node from the factory or a node that has been previously used as an IMM node:

Procedure

Use the MAC address or slot number to determine whether the failed node is CPM-A or CPM-B. The node to be added as a CPM-IMM node must be configured based on which one failed. For the purposes of this example, it is assumed that CPM-B (the standby CPM) has failed.
Disconnect the stacking port on the failed node and complete the stacking ring.
On the active CPM, remove the configuration of the failed CPM-IMM node (CPM-B) from the BOF using the bof no vc-stack-node command.
On the active CPM, add the configuration of the new CPM-IMM node as CPM-B to the BOF using the bof vc-stack-node command.
Save the BOF for the configuration to take effect immediately.
If the replacement node is an existing IMM-only node, follow these steps:
1. Remove the IMM-only node configuration from the configuration file of the active CPM using the config system vc-stack no vc-stack-node command.
2. Connect to the console of the IMM-only node.
3. Reboot the node by toggling the power button.
4. On boot up, interrupt the boot process and configure the node as CPM-IMM (CPM-B) by configuring the following BOF parameters:
  - specify cpm-imm for vc-stack-node-type
  - specify the slot number and MAC address of each CPM-IMM node in the bof>vc-stack-node command
If the replacement node is a new node, follow these steps:
1. Physically connect the new node into the VC ring (the stacking ports are connected to form a ring so that an alternate path always exists).
2. Reboot the node.
3. Connect to the console of the new node.
4. Power on the node.
5. On boot up, interrupt the boot process and configure the node as CPM-IMM node by configuring the following boot loader parameters:
  - specify cpm-imm for vc-stack-node-type
  - specify the slot number and MAC address of each CPM-IMM node in the bof vc-stack-node command
Save the BOF and allow the boot to proceed.

The node comes up as a standby CPM node and talks to the active CPM to start the HA synchronization process. The master LED on the standby CPM will be blinking. The master LED on the active CPM will glow steady.

Expected outcome

Services are not interrupted during the preceding process because the active CPM (CPM-A) is present and has not been rebooted (assuming the active CPM has an uplink to the network). If one of the IMM-only nodes was converted to a CPM-IMM node, the services on that IMM are affected as the node is rebooted to effect the change to a CPM-IMM node.