This is a...

• Feature Request
• Bug Report

Problem:
In the section Staging an Update the partition value was 3 and web-2 is not modified because:

the ordinal of the Pod is less than the partition specified by the updateStrategy.

I guess the sentence from the Rolling Out a Canary section is somehow wrong:

When you changed the partition, the StatefulSet controller automatically updated the web-2 Pod because the Pod’s ordinal was less than or equal to the partition.

I think it should be "greater than or equal to the partition." because in this case partition value is 2 and web-2 ordinal is 2 (equal) but it doesn't change the other pods (web-0 and web-1).

Proposed Solution:
Change the "less than" by "greater than":

When you changed the partition, the StatefulSet controller automatically updated the web-2 Pod because the Pod’s ordinal was greater than or equal to the partition.

Page to Update:
http://kubernetes.io/docs/tutorials/stateful-application/basic-stateful-set/

Client Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.2", GitCommit:"5fa2db2bd46ac79e5e00a4e6ed24191080aa463b", GitTreeState:"clean", BuildDate:"2018-01-18T21:12:46Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"8", GitVersion:"v1.8.0", GitCommit:"0b9efaeb34a2fc51ff8e4d34ad9bc6375459c4a4", GitTreeState:"clean", BuildDate:"2017-11-29T22:43:34Z", GoVersion:"go1.9.1", Compiler:"gc", Platform:"linux/amd64"}

I can open a PR to fix it if you confirm me that I'm not mistaken.

Regards