APS: Application requirements

Refers to:

  • Plesk 11.5 for Linux


2016-11-16 13:14:53 UTC


2016-12-21 20:16:52 UTC


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APS: Application requirements

APS Application Requirements

Every single APS application may have its own requirements defined as aspects in the APP-META.xml file in APS package.

There may be two kinds of requirements:

  • Installation requirements - an application may be installed only ifprovisioning server has required components/modules (such as PHP, ASP.NET) orcustomer subscription has required resources (e.g. database).

  • Provisioning requirement - requirement to provision sub-service of anapplication.

Installation requirements usually apply to applications of the Shared Web Server and Dedicated VPS provisioning types, provisioning requirements may apply to applications of External System provisioning type as well.

The example of installation requirement is the following one - an applicationcan only be installed on shared hosting server that has particular version ofPHP (for example, PHP 5 in CGI mode) and can require specific version of MySQLdatabase.

An example of provisioning requirement (see the table below):

  • Mail requirement:

    • To provision Open-Xchange webmail access a mailbox is required

    • To archive mailbox via Liveoffice a mailbox is required as well

  • DNS Zone requirement

    • SPAM protection solutions like SpamExperts or McAfee require to changeMX records for a domain they are being installed to to check incoming mail

    • Microsoft Office 365 uses DNS requirement to create a record needed fordomain verification by Microsoft

Common aspects are as follows:

Aspect Example of requirement type
PHP Minimal and maximal version, extenstions, limits
ASP.NET Version
Database Database type, version, privileges
Apache Modules, .htaccess
IIS Version, application pool type
CGI Extensions (e.g. Perl, PHP, Python)
Hardware CPU, RAM (minimal and recommended)
Operating Environment OS type, architecture
Mail Mailbox access types (POP, IMAP)
Perl Version, modules
DNS Zone DNS records types

POA does check the requirements before it provisions application.

How POA checks requirements when provision application in 'Site Application' model.

In this provisioning scenario application is being installed on existingdomain to existing customer's webspace:

  1. POA checks application requirements defined in the APP-META.xml file
  2. PHP, database, web server (Apache/IIS) and so on.

  3. POA already knows what webspace application will be provisioned to so itchecks whether target server (where webspace is located) supports necessaryversion of scripting language (PHP in most cases) and required extensions.

  4. If application requires database of certain type (MySQL 4, MySQL 5,PostgreSQL, MsSQL) POA checks resources of customer's subscription to see ifthere are available resources to create particular database type.

If all checks are passed successfully, POA allows customer to installapplication.

How POA checks requirements when provision application in 'SaaS Application' model.

In this scenario customer's subscription includes only APS applicationresource so POA does the following:

  1. Checks provisioning attribute(s) assigned to APS application resourceincluded into a customer's subscription, e.g. WordPress.

  2. Looks for a resource based on ' Physical Hosting (Apache) ' resourceclass (or 'Physical Hosting (IIS) ' if application is provisioned onWindows) with the same attribute(s) as application resource. In thisprovisioning scenarion the resource does not have to be included in customer'ssubscription, it just must exist in system.

  3. If application requires database, POA also looks for database resourcewith the same attribute(s) as application resource. Again, this resource doesnot have to be included in customer's subscription, it just must exist insystem.

  4. After POA found necessary web hosting and database resources, it startslooking for shared hosting servers that have:

    1. necessary services (Apache/IIS and database server)

    2. the same attribute(s) as application resource has

    3. required version of PHP (or another scripting language required byapplication)

  5. If all required components are found, POA provisions application:

    1. creates webspace based on activation parameters of resource type foundon step 2

    2. creates database based on parameters of resource found on step 3

    3. installs application into the webspace using created database (if it isrequired)

See the main KB article #115664 APS: General information, Best Practices and Troubleshooting for more information.

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