Avoiding an ISSUe on the Nexus 5000
The idea for this post came from someone I was working with recently. Thanks Fan (and Carson, and Shree) :-)
In Service Software Upgrade (ISSU) is a method of upgrading software on a switch without interrupting the flow of traffic through the switch. The conditions for successfully completing an ISSU are usually pretty strict and if you don't comply, the hitless upgrade can all of a sudden become impacting.
The conditions for ISSU on the Nexus 5000 are pretty well documented (cisco.com link) however, there are a couple bits of knowledge that are not. This post is a reminder of the ISSU conditions you need to comply with and a call out to the bits of information that aren't so well documented.