Enabling the High Availability-CPU (HA-CPU) mode

About this task

Enable High Availability-CPU (HA-CPU) mode to enable devices with two CPUs to recover quickly from a failure of the master CPU.

1. Enter Global Configuration mode:

   enable

   configure terminal

2. Configure the following boot flag:

   boot config flags ha-cpu

   The configuration file is saved on both the CPUs. After you disable HA mode on the master CPU, the secondary CPU software automatically resets and loads the settings from the previously-saved configuration file.

3. Type y after displaying the following prompt:
   

   Do you want to continue (y/n) ?

   Responding to the user prompt with a y causes the secondary CPU to reset itself automatically, and that secondary CPU restarts with HA mode enabled.

4. Save the configuration.

Example

Switch:1>enable
Switch:1#configure terminal

Enable HA mode:

Switch:1(config)#boot config flags ha-cpu
The config files on the Master and Slave will be overwritten with the current active configuration.
-Layer 2/3 features will be enabled in L2/L3 redundancy mode.
Do you want to continue (y/n)?y
Boot configuration is being saved.
CP-1: Save config to file /intflash/config.cfg successful.
CP-2: Save /intflash/config.cfg to standby successful.
Runtime configuration is being saved.
Resetting Slave CPU from Master CPU. 
CP1 [01/07/17 15:21:50.605:UTC] 0x000045e3 00000000 GlobalRouter SNMP INFO Save config successful.
CP2 [01/07/17 15:22:16.890:UTC] 0x000105e3 00000000 GlobalRouter HW INFO HA-CPU: Table Sync is complete (Standby CPU)
CP1 [01/07/17 15:22:17.407:UTC] 0x000105c8 00000000 GlobalRouter HW INFO HA-CPU: Table Sync Completed on Secondary CPU

Verify the configuration:

Switch:1(config)#show ha-state
Current CPU State : Synchronized State.
Last Event : Table synchronization completed.
Mode : Warm Standby

Card Info :
        Slot#      CardType             Oper   Admin  Power
                                      Status  Status  State
            1        8624XS        up-Master      up     on
            2        8624XS   up-Warmstandby      up     on

Current Boot Config State: master 1

Save the configuration:

Switch:1(config)#save config

What to do next

Note

In HA-CPU mode, whenever there is a mismatch of boot config flags between the master CPU and the standby CPU, the standby CPU follows the master CPU. The mismatch could be due to different runtime config files or primary config files at standby CPU. Once the chassis boots up successfully on the switch, ensure that both the CPUs run the same primary config file and the running config file.