Oracle WebLogic Server 12cR2 is the world’s first cloud-native, enterprise Java platform that enables you to fully realize the benefits of cloud computing. It is so far one of the biggest WebLogic release from Oracle.
One of the interesting feature of Oracle WLS 12c R2 is Continuous Availability and Zero Downtime Patching helps in achieving the same.
Zero Downtime Patching allows you to rollout distributed patches to multiple clusters or to your entire domain with a single command. All without causing any service outages or loss of session data for the end-user.
Zero Downtime (ZDT) automatically orchestrates rollout of patches and upgrades. You can patch or update any number of nodes in a domain with little or no manual intervention. Changes are rolled out to one node at a time, allowing a load balancer such as Oracle Traffic Director to redirect incoming traffic to the remaining nodes until the node has been updated.
ZDT Patching is also able to revert an update at any point in the process, even after it has completed.
One can rollout/revert Patch and upgrade to the following components through ZDT:
1) Oracle Home
2) Java Home
You can use OPatchAuto, WLST to create and monitor the workflow or you can create and monitor the workflow via the WebLogic Server Administration Console.
The admin console 12c R2 now have a ZDT Control tab in domain which can be used to create and monitor the patching and upgrade. You can also find workflow progress section under the ZDT tab which allows you to monitor the progress of your patching.
ZDT also allows you to do a Dry run any upgrade wherein one can check the upgrade and patching without actually committing it in real sense.
Note : This feature is available with Oracle WebLogic Server 12cR2 as a value-add offering for WebLogic Server Enterprise Edition and WebLogic Suite customers and includes the WebLogic Coherence Grid Edition Option.
For more information, you can refer here.