Now it’s time for the really good stuff!
In this post, you will see how Zero Downtime (ZDT) Patching can be used to rollout a
patched WebLogic OracleHome directory to all your managed servers (and optionally to your AdminServer) without incurring any downtime or loss of session data for your
This rollout, like the others, is based on the controlled rolling shutdown
of nodes, and using Oracle Traffic Director (OTD) load balancer to route user
requests around the offline node. The
difference with this rollout is what happens when the managed servers are shut
down. In this case, when the managed
servers are shutdown, the rollout will actually move the current OracleHome
directory to a backup location, and replace it with a patched OracleHome
directory that the administrator has prepared, verified, and distributed in
advance. (More on the preparation in a
When everything has been prepared, starting the rollout is simply a matter
of issuing a WLST command like this one:
The AdminServer will then check that the PatchedOracleHome.jar file exists
everywhere that it should, and it will begin the rollout. Note that the “FALSE” flag simply indicates
that this is not a domain level rollback operation where we would be required to update the
AdminServer last instead of first.
In order to prepare the patched OracleHome directory, as mentioned above,
the user can start with a copy of a production OracleHome, usually in a test
(non-production) environment, and apply the desired patches in whatever way is
already familiar to them. Once this is
done, the administrator uses the included CIE tool copyBinary to create a
distributable jar archive of the OracleHome. Once the jar archive of the patched OracleHome directory has been
created, it can be distributed to all of the nodes that will be updated. Note that it needs to reside on the same path
for all nodes. With that, the
preparation is complete and the rollout can begin!
Be sure to check back soon to read about how the preparation phase has been
automated as well by integrating ZDT Patching with another new tool called
For more information about updating OracleHome with Zero Downtime Patching,
view the documentation.