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This section covers specific configuration requirements for: Application servers
and their clients Desktop servers that provide special services—database
servers, icon servers, and help servers
It also covers networking requirements for two special configurations
for networked applications: Applications running across file system mounts
Search Path Environment Variables | |
The desktop uses a set of environment variables to specify
the search path used to find application desktop configuration files
such as the actions and data types database, help files, and icon
files. For information on how to use the search path environment
variables, see Chapter 7 “Desktop
Search Paths”''
or the dtenvvar(5) man
page. Configuring an Application
Server and Its Clients | |
In the standard application server configuration, the application
server contains all the binary and configuration files associated
with the application, including: The application
executable(s) Standard application configuration files such as
app-defaults, message catalogs, and shared libraries for that application. Desktop configuration files: Action and data
type definition files
To Configure
an Application ServerTo Configure
the Client of an Application ServerFor example, the following line in /etc/dt/config/Xsession.d/0010.dtpaths
adds a system with hostname SysAAA
and SysBBB to the application
search path: DTSPSYSAPPHOSTS=SysAAA:,SysBBB: |
For more information about setting the application search
path, see: Configuring
Database, Icon, and Help Services | |
Usually, the action and data type definitions, icons, and
help data files associated with an application are installed onto
the same system as the application. For example, consider the typical configuration of help data
files: The help files for
File Manager are usually located on the session server. The desktop
finds them because the help search path automatically searches the
proper locations on the session server. The help files for other applications are usually
located on the same application server as the application. The session
server finds them because modifying the application search path
automatically modifies the help search path.
There may be situations in which you want to place database
(actions and data types), help, or icon data elsewhere on the network.
For example, if your network uses multiple session servers, you
might want to create a help server on which all the help data files
for desktop applications (File Manager, Style Manager, etc.) are
stored. This conserves disk space because the help files do not
need to be duplicated on each session server. To Create a Database, Help, or Icon
ServerProvide the operating system network configurations required
by the desktop. See “Configuring
Base Operating System Networking for the Desktop”. Provide the general desktop configuration required
for clients. See “To Configure Desktop Clients and Servers”. Install the database, help,
or icon files. The files can be located anywhere on the system. However,
it may be easier to use the following locations, since these are
the directories automatically searched when a system has been designated
an application server. Database files:
/etc/dt/appconfig/types/language Help files: /etc/dt/appconfig/help/language Icon files: /etc/dt/appconfig/icons/language
If you are setting up a database server, the actions must
be written to specify where their commands (EXEC_STRINGs)
will run. See “Specifying
a Remote Execution Host”.
To Configure
the Session Server to Find a Database, Icon, or Help ServerProvide the operating system network configurations required
by the desktop. See “Configuring
Base Operating System Networking for the Desktop”. Provide the general desktop configuration required
for clients. See “To Configure Desktop Clients and Servers”. Add the database, icon, or help server to the appropriate
search path. If you placed the
data files in the locations specified in “To Create a Database, Help, or Icon
Server” you can modify the application
search path. If you placed the data files in other locations,
you must modify the specific search path. For example, if you placed the help files in directory /etc/dt/help
on system SysCCC, you would
add the following line to /etc/dt/config/Xsession.d/0010.dtpaths: DTSPSYSHELP=/net/SysCCC/etc/dt/help |
For more information about setting search paths, see:
Special Networked Application
Configurations | |
This section describes how to configure systems to run applications: Elsewhere than on
the system containing the action—on a remote execution
host Locally across file system mounts
Specifying
a Remote Execution HostIn the typical application server configuration, the action
definition is located on the same system as the application executable.
However, actions can be written
to execute commands on other systems. In this configuration, the
system containing the application is called the execution
host.< The action definition may be located on the session server
or on a system that provides action and data type services to the
session server—called a database
server or database host. Action definitions use the EXEC_HOST
field to specify where their commands (EXEC_STRINGs)
should be run. For example, the following action definition specifies
that an xload client be run
on a system with host name SysDDD: ACTION XloadSysDDD
{ TYPE COMMAND
EXEC_HOST SysDDD
EXEC_STRING /usr/bin/X11/xload -label SysDDD
} |
If the EXEC_HOST
field specifies more than one host name, then the desktop tries
to execute the EXEC_STRING
on each host in order until it finds one that can run the action.
For example, the following EXEC_HOST
field specifies that the action should first attempt to run the
EXEC_STRING on SysDDD,
and, failing this, try SysEEE. If the EXEC_HOST
field is not set for an action, it defaults to the value %DatabaseHost%.
The value of %DatabaseHost%
is obtained from the database search path. For example, suppose the database search path has been modified
by adding the following line to /etc/dt/config/Xsession.d/0010.dtpaths: DTSPSYSDATABASEHOSTS=SysAAA:,/net/SysBBB/etc/dt/appconfig/types/C |
SysAAA is specified using
the host-qualified syntax—SysAAA:.
An action definition found using this element of the search path
sets the database host to SysAAA.
However, an action found using the /net/SysBBB...
portion of the search path sets the database host to the local system
because the syntax does not include the host qualifier. To Configure the Remote Execution
HostTo Configure the System Containing
the Action DefinitionTo Configure the Session ServerRunning Applications LocallyThe standard application server configuration runs applications
on the application server. Sometimes it is desirable to have the
application installed on a remote system but executed locally on
the session server. To Configure the Application
ServerNo special configuration is required. To Configure the Session ServerModify the application search path. Use the local absolute
path to the application.
For example, you might use the following variable definition
to find an application registered on sysAAA: DTSPSYSAPPHOSTS=/net/SysAAA/etc/dt/appconfig/appmanager/C |
The session server must be able to access the application's
configuration files, such as app-defaults, message catalogs, and
shared libraries. |
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