Installation process is done with yum:
When completed - run a command to setup mod_lsapi and register LSPHP handlers in Plesk Panel:
The command adds LSPHPXY alt-php PHP handlers to Plesk Panel so they become available for domains.
Managing PHP handlers is fully done with Plesk Admin according to their documentation: http://download1.parallels.com/Plesk/PP12/12.0/Doc/en-US/online/plesk-administrator-guide/70669.htm
Enabling lsapi for single domain is done with Plesk Panel > Subscriptions > [subscription name] > Hosting Settings > PHP Support, select desired LSPHP handler for domain.
Enabling lsapi for multiple domains is done with Plesk Service Plans > [Plan name] > PHP Settings > PHP support, select desired LSPHP handler to be used by all users under a plan. If a subscription is not locked (user changed nothing in it), after clicking ‘Update and sync’ domains will start using lsapi.
There is no way to switch all plans to lsapi - it should be done one-by-one .
How to run LiteSpeed PHP (mod_lsapi) with PHP Selector
1. Chose Plesk PHP Settings
From the dialog box, select LSPHP by Vendor OS PHP version.
Click Apply and OK to confirm.
2. Now you can manage your PHP (versions and modules) from PHP Selector.
Chose PHP Selector.
From the dialog box select proper PHP version and PHP modules (or defaults).
Click Save and Set as current to apply your choice.
From now on, on your domain will be applied PHP with version and modules which are set by PHP Selector handled by mod_lsapi.
1. For correct work of PHP Selector - chose for domain "LSPHP by vendor OS".
2. If any other LSPHP version is chosen in Plesk, then PHP Selector will not be available anymore.
3. For enabling native PHP from the vendor, select "native" on the PHP Selector management page.