Sunday, February 20, 2011

Upgrading Oracle Glassfish Server to v. 3.0.1

Since version 3, Oracle Glassfish Server, formerly known as Sun Glassfish Enterprise Server, bundles an IPS-based "update tool" that makes life easier to system administrators while upgrading their Glassfish instances.

The update tool, a standalone GUI application, has been integrated into the Glassfish Admin Console since version 3.0.1, and can now be easily used to check installed components or available package updates.

The update tool can be found at $GLASSFISH_ROOT/updatetool/bin/updatetool or, starting with version 3.0.1, at $GLASSFISH_ROOT/glassfishv3/bin/updatetool.

Sometimes, though, administrators prefer using a safer upgrade path than patching a running instance, in case they need to quickly rollback to the previous instance in case something goes wrong.

As described in the official Glassfish documentation, administrators can now use the asupgrade tool to upgrade an existing Glassfish domain to a new installation path so that, if the upgraded instance does not work properly, they can fall-back to the old one.

Upgrading Glassfish using the asupgrade tool is straightforward:

  • Install the Glassfish instance you're going to upgrade to. If you're using the zip distribution, just unzip it.
  • Stop the domain to be upgraded.
  • Launch the asupgrade tool to upgrade a Glassfish domain:
asupgrade [-c] \
  --source /old/domain/path
  --target /new/domain/root/path

The optional -c option instructs asupgrade to use the upgrade command line utility instead of the default GUI upgrade utility. This is handy when you need to upgrade instances on remote machine and you cannot, or wish not, use a GUI interface.

Please note that the --source argument points to a domain while the --target argument points to a domain root. You should, then, use something like this:

asupgrade -c \
  --source /opt/ogs-3/glassfish/domains/domain1
  --target /opt/ogs-3.0.1/glassfish/domains

Depending on your domain name, the tool may ask you whether you wish to rename an existing domain on the new server instance. That's typically the case when you're upgrading a domain called domain1 since the default Glassfish installation bundles a domain with such a name.

The tool will start the upgrade process that will be logged in the upgrade.log file for later inspection. If the upgrade process finishes correctly, you can now start the upgraded instance and check that all of your applications work as expected.

So far, I haven't experienced any major problem with the asupgrade tool and it's a very easy upgrade process that takes care of everything. Resources such as data sources, connection pools, JavaMail sessions, were all replicated correctly on the destination server. The tool even took care of copying the database drivers from one instance to another.

The only glitch I experienced is being unable to start the server without cleaning up the OSGi cache first but that's easily solved.

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