Best Practices |
Typically you can apply hot fixes directly on your staging environment and QA the applied hot fix. Once every one has signed off on the fix, it can be deployed on to your production environments.
Applying upgrade patches is a little more tedious then upgrading because the rollback option is not applicable. You can apply an upgrade patch first either in QA or a development environment depending on whether you are working on a major or minor version upgrade.
We suggest you can apply minor versions in a QA environment and go through the QA process then propagate those changes to staging and production.
In case of major version upgrade you need to apply it on a development environment first. Typically we strive for 100% backward compatibility but in certain scenarios you may have to deal with minor configuration issues and also develop existing processes with enhanced features then propagate those changes to the QA, Staging, and Production environments.
Also when applying upgrades it is good practice to pull out the single staging or production box from the cluster or load balancer environment, that way you can minimize your risks.