Installing TREX with Virtual Host Names

To make it possible to access your TREX using a virtual host name, you have to rename the host name of the host on which you intend to install TREX. To do so, proceed as follows:

• Change the host name to the virtual host name

  Before you install TREX you change the name of the installation host to a virtual host name on operating system level.

• Install TREX and change the host name back

  After you have installed TREX on the installation host you change the host name back to the original host name.

• Change the TREX Settings

  To make the virtual host name work for your TREX installation you need to change some TREX settings.

Prerequisites

The virtual host name must be valid at the operating system level, and the host must be part of the network. It can be a new primary host name, an additional alias name, or its IP address. The host must be accessible with this name using the ping command. Only then TREX can monitor itself and can be used by other applications.

Change the Host Name to the Virtual Host Name

Before you install TREX you change the host name of the host on which you intend to install TREX to a virtual host name on operating system level.

UNIX

1. Log on to the installation host as user root.
2. Change the host name of your installation host by the command hostname <virtual_hostname>.
   Note

   The host name is usually set once at system startup by reading the contents of a file which contains the host name, for example /etc/hostname.

Windows

1. Log on to the installation host as user with administrator rights.
2. Choose Start → Control Panel → System.
3. On the Computer Name tab, choose Change.
4. In the field Computer name, enter your new virtual host name <virtual_hostname>.
   Note

   The name must be unique. You cannot use a name already in use on the network.

5. You need to restart your host for the new settings to take effect.

Install TREX and Change the Host Name Back

After you have installed TREX on the installation host you change the host name back to the original host name.

1. Install TREX as described in the TREX installation guide.
   Note

   You can find the TREX Installation Guide on SAP Service Marketplace at service.sap.com/instguides.

2. Stop TREX if necessary (including sapstartsrv).
   • On Windows, you use the SAP Management console, a snap-in in the Microsoft Management Console Windows (MMC), to start and stop SAP systems and TREX instances.
   • On UNIX, you use the shell scripts startsap and stopsap to start and stop SAP systems and TREX instances.
     Note

     As long as the host name is changed to the virtual host name, do not start or stop any TREX instances. Otherwise, those TREX instances would change the TREX configuration file toplogy.ini so that the instances will be registered with the virtual host name there.

3. Change the virtual host name <virtual_hostname> of your installation host back to the original host name as described in the step Change Host Name to Virtual Host Name.

Change the TREX Settings

To make the virtual host name work for your TREX installation you have to specify the following TREX settings.

Only on UNIX:

1. Create a file with the name hostname in the home directory of the <sapsid>adm user with the following content:

   #!/bin/sh

   echo <virtual_hostname>

2. Make the file hostname executable by the command chmod+x hostname.

Windows and UNIX

Change the TREX profile files START_TRX<instance_number>_<virtual_hostname> and sapprofile.ini:

1. Change the TREX start profile START_TRX<instance_number>_<virtual_hostname> in the global file system for your TREX installation <TREX_GLOBAL> (/usr/sap/<SAPSID>/SYS/profile).

   Change the line SAPLOCALHOST=<virtual_hostname>. If there is a line SAPGLOBALHOST=<old_hostname> then also change it.

2. Change the configuration file <TREX_DIR>/<virtual_hostname>/sapprofile.ini.

   Change the line SAPLOCALHOST=<virtual_hostname>. If there is a line SAPGLOBALHOST=<old_hostname> then also change it.

3. Start TREX.
   • On Windows, you use the SAP Management console, a snap-in in the Microsoft Management Console Windows (MMC), to start and stop SAP systems and TREX instances.
   • On UNIX, you use the shell scripts startsap and stopsap to start and stop SAP systems and TREX instances.