Description

This article provide information on MC-LAG Fabric upgradation.
Disable the MC-LAG & upgrade the MC-LAG peers as standalone units. After the software has been upgraded on both MC-LAG peers, you'll re-connect them & re-establish the MC-LAG.

Symptoms

Diagram:
 

Topology


 

Solution

Upgradation

The manual upgrade process uses a HA design to systematically remove one device from services in order to perform the upgrade & then reboot. When servers are dual-homed to each MC-LAG peer, the network can handle the removal of one of the MC-LAG peers during the upgrade window. There's a reduction of overall network bandwidth during the process, but the network remains available (It ensures minimum downtime).
  • Verify that the MC-LAG state is operational between both MC-LAg peers.
user@EX9251-A> show interfaces mc-ae
user@EX9251-A> show iccp
user@EX9251-A> show lacp interfaces ae0
user@EX9251-A> show lacp interfaces ae1
user@EX9251-B> show interfaces mc-ae
user@EX9251-B> show iccp
user@EX9251-B> show lacp interfaces ae0
user@EX9251-B> show lacp interfaces ae1
 
  • Copy the new JUNOS OS software image to the /var/tmp/ directories on both peers.
user@EX9251-A> file copy http://server.juniper.net/<destination-path-to-junos-os-file> /var/tmp/
 
  • Disable the server-facing interfaces on EX9251-A to minimize disruption during the switchover to EX9251-B.
set interfaces xe-0/1/1 disable
commit and-quit
 
  • Disable the uplink interfaces on EX9251-A.
set interfaces xe-0/1/4 disable
commit and-quit
 
  • Disable the interfaces between the EX9251-A & EX9251-B. This breaks up the MC-LAG
user@EX9251-A> set interfaces xe-0/1/2 disable
user@EX9251-A> set interfaces xe-0/1/3 disable
user@EX9251-A> commit and-quit
user@EX9251-B> set interfaces xe-0/1/2 disable
user@EX9251-B> set interfaces xe-0/1/3 disable
user@EX9251-B> commit and-quit
Disabling Interfaces Between EX9251-A and EX9251-B
  • Upgrade EX9251-A.
user@EX9251-A> request vmhost software add /var/tmp/<junos-os-filename>
 
  • To redirect the traffic from EX9251-B to EX9251-A, re-enable the server-facing & uplink interface on EX9251-A.
user@EX9251-A# delete interfaces xe-0/1/1 disable
user@EX9251-A# delete interfaces xe-0/1/4 disable
user@EX9251-A# commit and-quit
 
  • Disable there server-facing interfaces on EX9251-B.
user@EX9251-B# set interfaces xe-0/1/1 disable
user@EX9251-B# commit and-quit 
Disabling Server-Facing Interfaces on EX9251-B
  • Disable the uplink interfaces on EX9251-B, so that the traffic goes thorough EX9251-A.
user@EX9251-B# set interfaces xe-0/1/4 disable
user@EX9251-B# commit and-quit
Disabling Uplink Interfaces on EX9251-B
  • Upgrade EX9251-B
user@EX9251-B> request vmhost software add /var/tmp/<junos-os-filename>
 
  • Re-enable the ICCP-PL interface between EX9251-A & EX9251-B.
user@EX9251-A> delete interfaces xe-0/1/2 disable
user@EX9251-A> delete interfaces xe-0/1/3 disable
user@EX9251-A> commit and-quit
user@EX9251-B> delete interfaces xe-0/1/2 disable
user@EX9251-B> delete interfaces xe-0/1/3 disable
user@EX9251-B> commit and-quit
  • Re-enable the server-facing & uplink interfaces on EX9251-B.
user@EX9251-B> delete interfaces xe-0/1/4 disable
user@EX9251-B> delete interfaces xe-0/1/1 disable
user@EX9251-B> commit and-quit
Diagram Description automatically generated
 

Verify MC-LAG Fabric status

show interfaces mc-ae
show iccp
show lacp interfaces ae0
show lacp interfaces ae1
show version

Modification History

14th May 2023 >> KB is validated