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KB0058

How to Use Primary and Backup License Servers in a Caché Network

Applies to: Caché 4.0 and 4.1

Certain types of Caché license are capable of distributing License Units around a network of Caché servers. Distribution is performed by a License Server, which is a Caché system on which the license key has been installed. Other Caché systems do not require their own local license key. Instead, they contact the License Server using IP networking when they need to obtain or release a license for a process.

The License Server is critical to the operation of all Caché systems that use it. To provide resilience, it is advisable to operate two: a Primary License Server and a Backup License Server. Unfortunately, current InterSystems documentation on how to set this up is inadequate. This article aims to help.

Set-up is most easily performed using Caché Configuration Manager, as follows:

On the Primary License Server

Use Configuration Manager's Wizard button to Create a License. Leave the "Use a License Server" checkbox clear. Proceed through the wizard, entering the details you received from InterSystems.

On Configuration Manager's Advanced tab, expand the License subtree. Set "Start License Server" to "Yes". Expand the License Server subtree. Set the six entries as follows:

Primary Server Name /IPAddresshostname or IP address of this server
Primary Server PortLeave empty to take the default (4001) or enter a port
Backup Server Name /IPAddresshostname or IP address of the Backup License Server
Backup Server PortLeave empty to take the default (4002) or enter a port
Listener Name /IPAddresslocalhost or 127.0.0.1
Listener PortLeave empty to take the default (4003) or enter a port

When you OK the changes in Configuration Manager, you will be advised to restart Caché. Do this, and check that you can log in to this Caché system after the restart.

On the Backup License Server

Use Configuration Manager's Wizard button to Create a License. Leave the "Use a License Server" checkbox clear. Proceed through the wizard, entering the details you received from InterSystems. By doing this the same license is placed on both Primary and Backup License Servers. An alternative way of doing this is to copy the text file cache.key from the mgr directory of the Caché installation on the Primary License Server so that it also resides in the mgr directory of this server's Caché installation.

On Configuration Manager's Advanced tab, expand the License subtree. Set "Start License Server" to "Yes". Expand the License Server subtree. Set the six entries as follows:

Primary Server Name /IPAddresshostname or IP address of the Primary License Server
Primary Server PortLeave empty to take the default (4001) or enter a port
Backup Server Name /IPAddresshostname or IP address of this server
Backup Server PortLeave empty to take the default (4002) or enter a port
Listener Name /IPAddresslocalhost or 127.0.0.1

When you OK the changes in Configuration Manager, you will be advised to restart Caché. Do this, and check that you can log in to this Caché system after the restart.

On the Other Caché Servers

On Configuration Manager's Advanced tab, expand the License subtree. Set "Start License Server" to "No". Expand the License Server subtree. Set the six entries as follows:

Primary Server Name /IPAddresshostname or IP address of Primary License Server
Primary Server PortLeave empty to take the default (4001) or enter a port
Backup Server Name /IPAddresshostname or IP address of the Backup License Server
Backup Server PortLeave empty to take the default (4002) or enter a port
Listener Name /IPAddresslocalhost or 127.0.0.1
Listener PortLeave empty to take the default (4003) or enter a port

When you OK the changes in Configuration Manager, you will be advised to restart Caché. Do this, and check that you can log in to this Caché system after the restart.

Notes

  1. You don't have to use 4001, 4002 and 4003, but all the servers must be configured to use the same three ports.
  2. Configuration Manager's field help incorrectly states that the default for the Backup License Server is 4001. It is in fact 4002.
  3. If you opt to enter hostnames rather than IP addresses, beware of a Configuration Manager bug that rejects names matching names you have already given to UDP network connections. Work around this by using FQDNs (fully qualified domain names) or IP addresses, or by renaming your UDP network connections.

Last reviewed: Oct 25, 2001

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