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Installing a Zing License

Once you have obtained a Zing license file issued by Azul, copy the license file, license, to one of the following locations on your ZVM host:

  • /etc/zing/license
  • <ZVM-installation>/etc/license
  • <current-directory>/license
  • $HOME/.zing/license
  • <a directory of your choice>/license

If you copy the license file to any other location of your choice, then you must add -XX:ZingLicenseFile=<filename> to your ZVM instance launch command. Optionally, a directory that contains a license file can be specified in the -XX:ZingLicenseFile option. Zing scans the specified directory until it detects and validates a license file.

The following locations are checked for a license which is either a file or a directory in order of priority:

  1. the value of the -XX:ZingLicenseFile command-line option
  2. /etc/zing/license
  3. <ZVM-installation>/etc/license
  4. <current-directory>/license
  5. $HOME/.zing/license
  6. the environment variable ZING_LICENSE (useful when starting a Docker container with an installed Zing ZVM by adding --env ZING_LICENSE="$(cat some_directory/license)" as a command-line parameter)

If the license is a directory, the filename that contains the license does not matter.

Licenses allow ZVM instance launches up to the end of the day they are due to expire within the local timezone specified in the license.


Depending upon your license agreement with Azul, you might see messages showing your license is expired but the ZVM instance has been allowed to launch. If you see these messages, contact your Azul representative to extend your license.

To diagnose an error related to license validation, use -Xlog:license=debug. The diagnostic information helps understand the details of the license checkout failure.

Using Azul OEM Master License Key

The OEM license inspects the checksum of the JAR file for the bound application. Starting with Zing, applications where binding to main class create operation difficulties, can now successfully start with Zing with the-XX:ZingLic=<path to the OrgJarLock file> command-line option.

Contact [email protected] to obtain a signed Zing.OrgJarLock.For.Customer.jar. When the OrgJarLock file is available, use the following command-line options when running OEM applications with Zing:

  • -XX:ZingLic=<path to the OrgJarLock file> – specifies absolute or relative path to the Zing.OrgJarLock.For.Customer.jar.
  • -XX:ZingLicTmpDir=<path to the OrgJarLock temporary files> – specifies an alternative location for the OrgJarLock temporary files. By default, ZVM extracts temporary files from OrgJarLock to /tmp/oemlicdata/<pid>.XXXXX, where pid is a PID of the process, XXXXX is a random temporary filename.

OrgJarLock temporary files are deleted after license verification. To keep them, use the -XX:-CleanZingLicTmpDir command-line option.

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