Web App on Linux is currently in Public Preview and enables customers to run their web apps natively on a Linux platform. This allows for better application compatibility for certain kinds of applications and makes it easier to migrate existing web apps hosted on a Linux platform elsewhere onto Azure App Services.
Customers can create web apps on Linux only within a Linux enabled App Service Plan and this App Service Plan can only host Linux-based web apps.
Public Preview pricing for Web App on Linux is 50% of the regular price, and the price is calculated by halving the number of compute-hours consumed by your App Service Plan.
No SLA is offered during the public preview period.