Before you get started with your upgrade, you might want to read the clustering and caching overview topics.
Clustering and caching interoperate closely on a clustered installation.
In addition, be sure to confirm that the plugins you're using are compatible
with the version you're upgrading to. In some cases, you might need to make
changes to plugins to ensure they work on the later version of the
application.
When you're upgrading from a version prior to 4.5.0 (and after 3.0.0), be sure to
follow the steps listed here. Note that you must upgrade from version 4.0.0
or later.
- Remove all plug-ins
from your existing instance. (You'll need to re-install them via the admin console after you've successfully upgraded).
- Stop all application server nodes in the cluster.
- Use the application package (such as the RPM on Linux) to set up a cache server
on a separate machine. See Setting Up a
Cache Server for more information. Note the cache server address for
use later in setting up application servers.
- Before proceeding, make sure the cache server you set up is running. It
must be running while you set up the application server nodes.
- On each node in the cluster, upgrade the application instance using the package
(RPM on Linux), but don't run the setup tool yet.
For
more information on upgrading the package, see Upgrading a Linux
Package.
- Start one web app node (and only one web app node) and navigate to its
instance with a web browser. Work through the upgrade tool, allowing
it to run the upgrade tasks it lists.
- Restart the application server you've upgraded and navigate to it with a
web browser again. In the setup screen provided, enter the address
of the cache server you installed, then complete the setup
tool.
- After you've finished with the setup tool, restart the application server.
- Start the application server on each of the other nodes. Because it's connecting
to the same database used by the server on the node you've already set up, the
server on each subsequent node will detect that clustering is enabled. Each will
also pick up configuration you set on the first node.
- After setting up all of the application server nodes and running them once,
restart all servers in the cluster to ensure that the address of each node in
the cluster is known to all the other nodes. The entire cluster must be bounced
after all the nodes are set up.
- You can now reapply any plugins you installed. See Post-Upgrading Tasks for your next steps.