24.1 Floating License Architecture

ClearCase implements an active-user floating license scheme. To use ClearCase, a user must obtain a license, which grants the privilege to use ClearCase commands and data on any number of hosts in the local area network. When a user runs a ClearCase client utility, such as cleartool or a GUI program, that utility attempts to obtain a license. If it gets one, the user can keep it for an extended period. Entering any ClearCase command renews the license. If the user doesn't enter a ClearCase command for a substantial period-by default, 60 minutes-another user can take the license.

One or more hosts in the local area network are designated as ClearCase license server hosts. Each license server host maintains a list of license keys. UNIX hosts maintain this list in a file named /var/adm/atria/license.db. Windows hosts store keys in the LicenseKeys value in the Windows Registry. Each license entry defines a specified number of licenses, allowing that number of ClearCase users to be active at the same time. See License Database Format for a description of the license database format.

When a user first attempts to use ClearCase software on any host in the network, a license-verification check is made:

• ClearCase client software looks for the name of the license server host. On UNIX, this name is stored in the file /var/adm/atria/config/license_host. On Windows, it is stored as the LicenseHost value in the Windows Registry key HKEY_LOCAL_MACHINE\SOFTWARE\Atria\ClearCase\CurrentVersion.

• ClearCase communicates with the license server process on the license server host, to verify the user's right to use ClearCase. (The license server process is actually albd_server, performing these duties in addition to its other tasks.)

• The license server process determines the user's rights and returns an appropriate message.

• Depending on the message the license server sends, the command either proceeds or is aborted.

Subsequently, similar license-verification checks are performed periodically.

License Priorities

Each user can (but need not) be assigned a license priority in the license database file. Each user specified in a -user line gets a priority number: the first user gets priority 1 (highest priority), the second user gets priority 2, and so on. All users who are not specified in any -user line share the lowest priority.

License Expiration

Each license entry can have an expiration date. (The expiration time is at 00:00 hours on that date.) During the 72-hour period before the expiration date, attempts to use a license from that license entry succeed, but a warning message appears. After the expiration time, attempts to use those licenses fail.

License Report Utility

The clearlicense utility produces a report on the licenses defined in the license database file and on current user activity. You can also use this utility to force a user to release a license, freeing it for use by another user.