Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Problem

Solution

Option 1: Clear Stack mode

Step 1: Clear the Stack Mode

Step 2: Reload the Stack

Step 3: Verify

Option 2: AssignSwitch with the Standby Role

Step 1: Setup Switch 2 as Standby

Step 2: Reload the Stack

Step 3: Verify

Related Information

Introduction

This document describes how to troubleshoot a stack of Catalyst 9000 switches missing Standby role.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

- Basic understanding of LAN Switching technologies

- Familiarity with Catalyst 9000 switch models

Components Used

The information in this document is based on these software and hardware versions:

- Hardware: Cisco Catalyst 9000 Series Switches

- Software Version: Cisco IOS XE

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Background Information

1:1 redundancy is used to assign active and standby roles to specific switches in the stack. This overrides the traditional N+1 role selection algorithm, where any switch in the stack can be active or standby. In 1:1 redundancy, the stack manager determines the active and standby role for a specific switch, based on the flash ROMMON variable. The algorithm assigns one switch as active, another switch as standby, designating all remaining switches in the stack as members. When an active switch reboots it becomes standby and the existing standby switch becomes the new active. The existing member switches remain in the same state.

In a network environment using Cisco Catalyst 9000 Series switches, an issue was observed where the standby switch role is missing. This document provides a detailed analysis of the problem and the steps to resolve it.

Problem

The problem was identified when the stack of switches does not have the standby role.

This is the output showing the issue:

Switch#show switch

Switch/Stack Mac Address : 8c44.a5a4.9d00 - Local Mac Address

Mac persistency wait time: Indefinite

H/W   Current

Switch#   Role    Mac Address     Priority Version  State

-------------------------------------------------------------------------------------

*1       Active   8c44.a5a4.9d00     15     V03     Ready

2       Member   8c44.a5a5.2380     14     V03     Ready                 <<< Missing Standby Mode

In the ROMMON variables, this value was observed:

Switch#show romvar switch all

<SNIP>

RET_2_RTS=

ROMMON_AUTOBOOT_ATTEMPT=3

STACK_1_1=1_0                 <<< This indicates that switch 1 is Active and no switch is marked for the Standby role

STACK_HIGH_SPEED=1

SWITCH_DISABLE_PASSWORD_RECOVERY=0

SWITCH_NUMBER=2

<SNIP>

This variable can be present on all or only 1 member of the stack. Can cause problems in both cases.

Solution

Option 1: Clear Stack mode

The stack mode needs to be cleared on the switches in the stack. Take these steps:

Step 1: Clear the Stack Mode

Switch# switch clear stack-mode

WARNING: Clearing the chassis HA configuration will result in both the chassis move into Stand Alone mode. This involves reloading the standby chassis

after clearing its HA configuration and coming up with all interfaces in shutdown mode. Do you wish to continue? [y/n]? [yes]: yes

Switch# copy running-config startup-config

Step 2: Reload the Stack

Switch# reload

Step 3: Verify

Switch#show romvar switch all

<SNIP>

RET_2_RTS=

ROMMON_AUTOBOOT_ATTEMPT=3

STACK_1_1=0_0                 <<< This indicate that no switch in the stack is marked as Active nor Standby. The switch will choose them upon booting

STACK_HIGH_SPEED=1

SWITCH_DISABLE_PASSWORD_RECOVERY=0

SWITCH_NUMBER=2

<SNIP>

This is the default value where the stack chooses the active and the standby role based on priority. If the stack mode has not been changed in the switch previously, the variable "STACK_1_1" does not show up in the ROMMON variables, indicating the value is in default (STACK_1_1=0_0).

Option 2: Assign Switch with the Standby Role

You can use the switch switch-number role command to set the standby switch in 1:1 stack mode. The stack operates in the 1:1 stack mode with the specified active or standby after reboot. In this example, switch 2 is assigned the standby role.

Step 1: Setup Switch 2 as Standby

Switch# switch 2 role standby

WARNING: Changing the switch role may result in redundancy mode being configured to 1+1 mode for this stack. If the configured Active or Standby switch numbers do not boot up, then the stack will not be able to boot. Do you want to continue?[y/n]? [yes]: yes

Step 2: Reload the Stack

Switch# reload

Step 3: Verify

Switch#show romvar switch all

<SNIP>

RET_2_RTS=

ROMMON_AUTOBOOT_ATTEMPT=3

STACK_1_1=1_2                 <<< This indicates that switch 1 is Active and switch 2 is the Standby

STACK_HIGH_SPEED=1

SWITCH_DISABLE_PASSWORD_RECOVERY=0

SWITCH_NUMBER=2

<SNIP>

Related Information

- Cisco Technical Support & Downloads

- Stack Manager and High Availability Configuration Guide