Before adding a new Compute Server, one must know:

1. How will the EASA Server and Compute Server communicate?
   • (rsh, ssh, WSCS or Excel Server?)
2. What software application(s) will run on the new Compute Server?

The first answer determines which object is set in the Server Processing: parameter of a COMPUTE SERVER object.

The second answer will define additions to SOFTWARE LIST, ENVIRONMENT LIST and LICENSING branches of the Tree. These objects will then be referred to in the Software: and Environment: parameters of a COMPUTE SERVER object.

A Windows Compute Server may communicate via:

• Web Service Server Processing
  • EASA Remote Server software with Compute Server service must be installed and running.
    • To install an EASA Remote Server, see Remote Compute Server Software.

• ssh server processing
  • Requires ssh server to be installed and running on compute server.
    • To install ssh see Remote Compute Server Software.

An Excel Server machine must:

• Run Windows.
• Have Microsoft Excel installed.
• Have the EASA Remote Server software with Excel Server service installed and running.
  • To install the EASA Remote Server, see Remote Compute Server Software.

The EXCEL SERVER PROCESSING object, which is specifically designed for configuring Excel Servers, is the only approach available for establishing the communication between the EASA Server and Excel Server. For an example of configuring an Excel Server, please see Configuring Compute Servers.

Tip: When configuring an Excel Server, you can usually use the existing default EXCEL SERVER PROCESSING object under DEFAULT SERVER PROCESSING. Exceptions include use of a 'Port Number' within the Remote Server software other than 80 or a change in the 'Username' and 'Password' for authenticating communications with Remote Servers.

Excel Add-ins are disabled by default in for EASA Excel processes for performance reasons, in most cases, full functionality is available without Add-ins.

If Excel Add-ins need to be enabled, add the line below, to the file:

• <SERVERDATA>\excel\admin\config\context.properties
  • easa.excel.server.use.pi.addins.reregister=true

Upon its first, initial invocation, Excel 2016 launches an interactive popup window, yet by default EASA Tomcat including the Excel Server runs as the non-interactive user, SYSTEM.

Unless this popup is manually closed by a user other than SYSTEM, the Excel Server cannot conduct any Excel-derived processing.

Excel 2016 users must therefore complete two essential tasks:

1. Create a new Windows user EASA-user → before installing EASA
   • Run Excel 2016 as EASA-user
   • Close the initial popup window
2. Configure the EASA Tomcat service to run as EASA-user → after EASA is installed

1. Create new Windows user, called EASA-user (for this example)
2. Log in in as EASA-user
3. Find and open Excel manually
4. Close the pop up which appears when EASA-user opens Excel 2016 for first, initial time.
5. Log out of Windows
6. Log in with the first user that was created when Windows was installed

Following EASA installation of the EASA Tomcat service, configure this service to run as EASA-user.

1. Go to services:
2. Right-click on the EASA Tomcat service
3. Click Stop
4. Right-click on the EASA Tomcat service
5. Click properties
6. Go to Log On Tab:
7. Select Log on as:→'This account:'
8. Enter EASA-user's credentials
9. Start the EASA Tomcat service

When configuring a UNIX or a Linux Compute Server, there are three communication approaches to choose from:

• Web Service Server Processing (Linux Only)
  • EASA Remote Server software with Compute Server service must be installed and running.
    • To install EASA Remote Server, see Remote Compute Server Software.
• SSH Server Processing
  • ssh server must be installed and running on Compute Server.
    • To install an ssh service, see Remote Compute Server Software.
• Standard Server Processing
  • Uses Remote Shell or rsh by default, so rsh needs to be installed and running.

If the third choice is selected, you can select from existing SERVER PROCESSING objects under DEFAULT SERVER PROCESSING. The table below provides guidance on the selection of the existing SERVER PROCESSING objects.

Also, with the third choice above and the use of rsh, there are a few important issues to be aware of:

• An .rhosts file containing the hostname or IP address of the EASA Server and the Username used to run it must be present on the Compute Server in the home directory of the User ID on the UNIX computer (See # 2 below).

Note: The settings for the owner, group and file permissions on the .rhosts file are also important. Set the owner to the User ID being used and the group to same group that the User ID belongs to. Finally, use file permissions of 600 or rw- --- ---.

1. A valid User ID on the Compute Server must be specified in the COMPUTE SERVER object for the server processing to function properly.
2. Using a directory on a mounted network hard drive for the Working Directory Path: parameter for multiple UNIX or Linux Compute Servers will reduce the number of SERVER PROCESSING objects required in the Compute Server configuration.

With Linux computers, one issue for concern is that rsh may not be activated and available for use by default in Linux. You can check whether rsh has been turned on by typing the following command in a shell window:

 chkconfig --list

You should then see a list of available services and their status. Look for the line corresponding to rsh. You will need to turn rsh on if you see the following in a shell window:

 rsh: off

You can turn rsh on by logging on the Linux computer as root and then typing the following command:

 chkconfig rsh on

To help configure Compute Servers, a flow diagram of the configuration process is provided: