Cisco ACI multi-site compatibility

October 3rd 2019

ACI Multi-Site Compatibility changes

We're in the process of upgrading an MSO cluster and wanted to share an important behavioural change that's been implemented in the Multi-Site 2.2 software.

According to the installation and upgrade guide:

"Prior to Release 2.2(1), you were required to run the same APIC versions in all sites and the version of the Orchestrator that corresponded to the APIC release. During fabric upgrade you were also required to upgrade all the APIC sites first before upgrading the Multi-Site Orchestrator. For example, if you were upgrading the fabrics from APIC release 4.0(1) to release 4.1(1), you had to remain on release 2.0(1) of the Orchestrator until all sites were on release 4.1(1).

Starting with Release 2.2(1), Multi-Site Orchestrator releases have been decoupled from the APIC releases. The APIC clusters in each site as well as the Orchestrator itself can now be upgraded independently of each other and run in mixed operation mode".

This may sound an insignificant change but this will make both MSO deployments and upgrades much easier and potentially less impacting.

For example, if you currently run 4.1(1i) on your APICs with 2.1(1i) on your MSO cluster, you may have a use case to upgrade your MSO cluster to a more recent version (2.2(1c)).

Before these recent changes, this would have required an upgrade of the APICs to 4.2(x). However, given that 4.2(x) has only just been released for the APICs, you can now choose to avoid upgrading the APICs immediately and perform the upgrade once the first maintenance release is ready. When taking this approach you should take into consideration that you can only leverage the features available within MSO that are supported within the APIC software release.

This is only a quick snippet but definitely a significant one.