Cadence FlexNet licensing is the mechanism by which Cadence products obtain and release their licences. Cadence states that its products “require a license server for license authorization” and that “the licenses of all the Cadence products are managed by FlexLM license management solution.”[2] The product acquires a licence from the server when it starts and gives it back when it closes.[2] For a software asset manager the practical consequences are that entitlement is expressed in a licence file, that the file is bound to a host, and that the licence server and its logs are the primary evidence of use. This article describes the pieces Cadence documents publicly.
The licence file
Cadence delivers licences as a file named license.dat. At first setup the Windows installer for OrCAD and Allegro products can install a licence manager with the Cadence-provided file: the administrator browses to the local directory where the file was saved.[2] The installer alternatively connects the products to an existing licence server by host name and port number.[2]
The file contains a SERVER line and FEATURE lines. The SERVER line has four items separated by spaces: the line type SERVER, a host name, a host ID and a port, in the form SERVER hostname hostid port.[1] The host name should match the name of the system hosting the server, and “the host ID in the license file must match the host ID of the system you are running the license server.” Host IDs are not case-sensitive but “cannot be edited in the license file.”[1] Cadence adds a prohibition on editing the licensed content: “Do not edit the FEATURE lines or the HOSTID in the SERVER line.”[1] A software asset manager should treat a hand-edited FEATURE line as a compliance finding in its own right.
Host IDs and dongles
The host ID is either an Ethernet address or a FLEXID dongle address.[1] The example SERVER lines in the guide show both forms, a 12-character Ethernet address and a FLEXID value. For dongle-based licences the guide says the dongle must be plugged in, and “the Flex ID of the dongle should match the FLEXID value in the SERVER line of the license file.” It shows the lmutil lmhostid -FLEXID command and the lmtools System Settings tab for reading the FlexID.[1] The Cadence blog adds that when a dongle is the locking method the installer’s silent mode should be used, with the dongle attached before installation so that the drivers are installed automatically.[2] The Cadence guide also points to the Software Manufacturing Completion Report shipped with the software as a record to compare against the host ID.[1]
Re-hosting is therefore a question for Cadence. The guide states that host IDs cannot be edited in the file, which implies that a different host needs a different file; it does not describe a re-host procedure, and it refers problems it cannot resolve to Cadence or the channel partner.[1]
When a FEATURE line is valid
The license server accepts only valid FEATURE lines. A line is valid when its start date is before the current system date at server start, the current date is before the expiration date on the line, and the 20-character encryption code is valid.[1] Two practical points follow. A term licence therefore stops working at its expiration date, with no grace behaviour documented in the guide. A server clock that has been moved outside the dated window will also cause licences to be rejected, so clock changes on licence servers are worth logging. The guide lists the products’ licence needs in a Product to Feature Map shipped with the Software Manufacturing Completion Report, which is the document that ties a feature name to a product.[1]
Daemons, versions and logs
The licence manager consists of the lmgrd server process and the Cadence vendor daemon, cdslmd. The guide’s server-status check enters cdslmd as the individual daemon and performs a status enquiry.[1] A Cadence support engineer states the version rule plainly: “you must ensure that the license daemon (cdslmd) and the license server (lmgrd) have the same version”, and both must match the version required by the product release.[4] A mismatch is described as the usual cause of unexpected check-in and check-out behaviour. On a 64-bit licence host the 64-bit daemons should be used, and the latest cdslmd and lmgrd come from the Cadence downloads site.[4]
The same rule drives upgrade planning. Cadence states for OrCAD X that “all major releases include new technology and package changes that require the license server to be upgraded”, while hot fixes and service packs do not unless the release notes say so.[5] An inventory of licence servers should therefore record the lmgrd and cdslmd versions beside the product releases they serve.
For evidence of use, Cadence documents an environment variable that writes licence activity to a file: setting CDS_LIC_QA_TesT makes the tool create a file recording licences that are checked out and checked in.[4] On Windows, the licence manager writes a debug.log, by default under C:\Cadence\LicenseManager, and Cadence asks customers who cannot resolve a licensing problem to send license.dat and the debug file with a screen shot of the error.[1]
How clients find the server
Clients locate licences through environment variables or a utility. On Linux examples, the Liberate documentation sets LM_LICENSE_FILE to a port@server value and sets CDS_LIC_FILE equal to it.[4] The earlier post shows the port@licsrvr form and tells the reader to check the value with the IT or CAD team.[3] On Windows, the License Client Configuration Utility points an installation at another server, and “you can specify multiple license servers separated by a semi-colon.”[2] The License Server Configuration Utility updates the licence file by pointing the server at a new license.dat.[2]
Search order and waiting behaviour matter for counting. The Liberate documentation describes licence queuing set by the ALTOS_QUEUE variable, a default wait of 86,400 seconds, and a —lorder option or LIBERATE_LORDER variable that sets the order in which licence types are tried and reduces queries to the server.[4] These are product-specific, but they show that the same entitlement can be consumed differently depending on client settings.
Counting on the server
Because the server distributes licences “until all the licenses for a given application are consumed”, peak concurrent use is visible from the server.[2] A Cadence engineer shows the check as lmstat -S filtered for the product name.[4] For tools that take several licences per run, the product rule decides what the log means. A Liberate run holds one server licence until the characterization ends and then takes client licences equal to its thread count, with a stated minimum of one server and ten client licences.[3] A la carte and token licences cannot be mixed within one run.[4]
Out of scope
This article does not cover redundant servers, licence option files, borrowing or the macOS CDS_LIC_PROXY_SERVER setting, none of which was retrievable as a Cadence-hosted document for this edition. It also does not cover contract remedies if a licence file is altered. Those follow the customer’s agreement.