Target environment
- C9000 Series switches
- version 17.3.x
Command log that you want to acquire when configuring the stack (at the time of construction)
This section describes which command log should be acquired as a normality check during construction when configuring a stack with C9000 series switches.
Since the normal log at the time of construction is a useful isolation material when trouble occurs at the time of local introduction, it is very important to acquire and store it.
The command list is as follows.
show switch detailshow switch stack-modeshow romvar
show switch detail
First is show switch detail. I think this is a command that goes without saying, but you can see the following information.
Role：Active/Standby/MemberMac AddressPriorityState：Switch stateStack Port Status
C9000#show switch detail
Switch/Stack Mac Address : aaaa.aaaa.aaaa - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
*1 Active aaaa.aaaa.aaaa 15 V01 Ready
2 Standby bbbb.bbbb.bbbb 1 V01 Ready
Stack Port Status Neighbors
Switch# Port 1 Port 2 Port 1 Port 2
--------------------------------------------------------
1 OK OK 2 2
2 OK OK 1 1 show switch stack-mode
The second command is show switch stack-mode. I think that some people have never used this.
You can check the following information with this command.
Role：Active/Standby/MemberMac AddressMode：Stack mode (N+1 or 1+1)Configured：Set stack role (role expected as the state after reboot)State：Switch state
C9000#show switch stack-mode
Switch# Role Mac Address Version Mode Configured State
--------------------------------------------------------------------------------------------------------------------
*1 Active aaaa.aaaa.aaaa V01 N+1 None Ready
2 Standby bbbb.bbbb.bbbb V01 N+1 None Ready About stack mode
Few people have been aware of this, but the stack on C9000 series switches has two modes:
N+1- Default mode
- The Mode value of the
show switch stack-modecommand isN+1
1+1- Used to assign Active and Standby roles to specific switches in the stack
- If you specify a role with
switch <スイッチ#> role <active|standby>command, it will automatically switch to 1+1 mode - Stack manager determines Active and Standby roles based on flash ROMMON variables
- The Mode value of the
show switch stack-modecommand is1+1
The display of show switch stack-mode when a role is specified by the switch <switch#> role command is as follows.
C9000#show switch stack-mode
Switch# Role Mac Address Version Mode Configured State
--------------------------------------------------------------------------------------------------------------------
*1 Active aaaa.aaaa.aaaa V01 1+1' Active' Ready
2 Standby bbbb.bbbb.bbbb V01 1+1' Standby' ReadyIf the values in the Mode and Configured fields are marked with “‘” as above, it means that you have manually changed the settings.
To return the stack mode to N+1, execute the following command.
# switch clear stack-mode
show romvar
The third command is show romvar. You can check the ROMMON variable with this command.
In 1+1 mode, the ROMMON variable is involved in the operation. Therefore, it may be useful to check the ROMMON variable.
C9000#show romvar
----------------------------------
ROMMON variables for Active Switch
----------------------------------
ABNORMAL_RESET_COUNT=0
AUTOBOOT_COUNT=0
AUTOBOOT_STATE=0
#The following is omittedIt is recommended to acquire this command log even when the stack mode is N+1.
Precautions in 1+1 mode
About role transition in case of failure
In N+1 mode, the role changes as follows in the event of an Active / Standby switch failure.
- In the event of an Active switch failure, the Standby switch will move to Active, and the member switch with the highest priority will move to Standby.
- In the event of a Standby switch failure, the member switch with the highest priority shifts to Standby.
On the other hand, in 1+1 mode, the movement is as follows.
- Standby switch transitions to Active in the event of an Active switch failure
- The Member switch remains a Member in the event of an Active or Standby failure
About starting the Member switch
In 1+1 mode, if you try to activate another switch (Member role switch) in the absence of both Active or Standby-configured switches (down), the switches will look like this: It is not possible to restart repeatedly with a log.
Chassis N reloading, reason - Active/standby selection failed in 1+1 ModeMember restarts also occur if both Active and Standby go down from the state in which each switch in the stack was up.
Chassis N reloading, reason - lost both active and standbyIf you want to start the Member switch without the Active and Standby switches, you need to remove the relevant ROMMON variable on the Member switch.
Please refer to the following PDF for details.
【PDF】Catalyst 9000 Switches booting to switch: prompt due to Stack 1+1 variable
References
【PDF】Catalyst 9000 Switches booting to switch: prompt due to Stack 1+1 variable
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