7. Upgrading From ERS 3.1 to ERS 4.0

This section describes how to upgrade an existing ERS installation from version 3.1 to version 4.0. The procedure first describes how to upgrade the 3.1 installation itself with the new 4.0 binaries, new versions of the Perl scripts, and so on. The procedure then describes how to migrate a 3.1 ERS server instance to one that uses the versions of Apache HTTP and Tomcat in ERS 4.0 (namely, Apache 2.2 and Tomcat 6.0).

7.1 Overview of Upgrade

As noted in earlier sections of this guide, ERS 4.0 is now distributed as a collection of separate packages that correspond to the main components of ERS (such as ERS httpd and ERS Tomcat.) This differs from how ERS 3.1 was packaged, in which all components were distributed together. For this reason, it is assumed in this procedure that you will continue to have a single directory for the entire ERS installation; this single directory will hold both the ERS httpd and ERS Tomcat components. If you want to "split up" your existing 3.1 ERS installation, then adjust the procedure in this section accordingly.

The procedure will use the default20 sample server instance (included in the 3.1 ERS installation) as an example of migrating an existing server so it uses the latest versions of Apache HTTP and Tomcat. Use this example as a guide when you migrate your own server instances.

Important: Before starting the upgrade, make a backup of your existing 3.1 ERS installation so that you can roll back if needed. VMware also recommends that you first upgrade your non-production ERS installations and servers as a practice before upgrading your production installations and servers.

The procedure below describes how to do an in-place upgrade. This means you simply install ERS 4.0 on top of your existing ERS 3.1 installation. ERS 4.0 is designed to support this type of upgrade, with a few caveats that are explicitly called out in the procedure.

Unpacking ERS 4.0 on top of your ERS 3.1 installation overwrites the perl5.8 directory, the two Perl scripts (fixrootpath.pl and ers-server.pl) and the licenses. Everything else in 4.0 is new, such as the new version of Apache HTTP (apache2.2), Tomcat (tomcat6.0), and so on.

ERS 4.0 includes two sample servers in the ERS-HOME/servers directory, but their names have changed since 3.1; the new names are test_apache2.2 and test-apache2.2-64. This means that when you perform an in-place upgrade, the old default13 and default20 sample servers are not overwritten. Nor, of course, are any server instances that you created in 3.1.

The other main caveat with the in-place upgrade is that the PHPINI directory changes from ERS 3.1 to ERS 4.0. You will have to replace all pointers to php4.4/ with php5.2. This is made easier because the fixrootpath.pl script can do it for you, as described in a step in the following procedure.