Overview
This section summarizes the upgrade process on a switch in a vPC topology that holds either the Primary or Operational Primary vPC roles.
In vPC topologies, the two peer switches must be upgraded individually. An upgrade on one peer switch does not automatically update the vPC peer switch.
In a dual-homed non-vPC access network (either a triangle or Y shaped access network), with or without STP configured, with BFD enabled and with HSRP configured on the SVIs and with HSRP configured as BFD client, transient traffic may drop for both IPv4 native unicast and/or labeled traffic after performing an ND-ISSU n fallback mode.
To counter this, configure in all the HSRP IPv4 groups for all the HSRP enabled SVIs the timer 2 120 on both HSRP peers prior to performing the ND-ISSU. The configuration of the timer 3 120 may lead to traffic loss.
Summary
Upgrading a vPC primary switch requires a coordinated process to update its software while minimizing network disruption, ensuring only the primary switch is upgraded at a time for operational stability. The upgrade involves compatibility checks, configuration locks, and a stateful restart. Thus, it involves coordinating several steps to update its software while minimizing disruption. This process ensures that only the primary switch is upgraded at a time, maintaining operational stability.
Workflow
Perform this upgrade procedure on a switch in a vPC topology that holds either the Primary or Operational Primary vPC roles.
Step 1 and Step 4 differ from a switch upgrade in a non-vPC topology.
- The install all command issued on the vPC primary switch triggers the installation upgrade.
- The compatibility checks display the impact of the upgrade.
- The installation proceeds or not based on the upgrade impact.
- The configuration is locked on both vPC peer switches.
- The current state is saved.
- The system unloads and runs the new image.
- The stateful restart of the system software and application occurs.
- The installer resumes with the new image.
- The installation is complete.
Result
When the installation is complete, the vPC primary switch is upgraded.
The vPC primary switch is running the upgraded version, and the vPC secondary switch is running the original software version.