We have been working with the Isilon engineering team to document the upgrade process from HDP 2.2. to HDP 2.3 when the underlying storage layer is OneFS instead of HDFS. The instructions in the blog post are to be used in conjunction with Ambari instructions on upgrading HDP.
Important to note that Isilon is working on making enhancements to OneFS to support rolling upgrade. This will be made available in an upcoming release of OneFS.