3.12. Software Collection Lock File Support

By default, programs packaged into a Software Collection create lock files in the /opt/provider/%{scl}/root/var/lock/ directory.

To make lock files more accessible and easier to manage, you are advised to use the nfsmountable macro that redefines the _localstatedir macro. This results in lock files being created underneath the /var/opt/provider/%{scl}/lock/ directory, outside of the /opt/provider/%{scl} file system hierarchy.

If applications or services packaged into your Software Collection write the lock underneath the /var/opt/provider/%{scl}/lock/ directory, then those applications and services can run concurrently with the system versions (when the resources of your Software Collection's applications and services will not conflict with the system versions' resources).

For example, a lock file mylockfile.lock is normally created in the /var/lock/ directory in the base system installation. If the lock file is a part of a software_collection Software Collection and the nfsmountable macro is defined, the path to the lock file in software_collection is as follows:

/var/opt/provider/software_collection/lock/mylockfile.lock

/var/opt/provider/software_collection/lock/mylockfile.lock/var/opt/provider/software_collection/lock/mylockfile.lock/var/opt/provider/software_collection/lock/mylockfile.lock/var/opt/provider/software_collection/lock/mylockfile.lock/var/opt/provider/software_collection/lock/mylockfile.lock/var/opt/provider/software_collection/lock/mylockfile.lock

For more information on using the nfsmountable macro, see Section 3.1, “Using Software Collections over NFS”.

If you want to prevent your Software Collection's applications or services from running while the system version of the respective application or service is running, make sure that your applications or services, which require a lock, write the lock to the system directory /var/lock/. In this way, your applications or services' lock file will not be overwritten. The lock file will not be renamed and the name stays the same as the system version.