Migrating FastCGI configuration from IIS 5.1/6.0 to IIS 7.0/7.5

Problem

As you know FastCGI functionality on IIS 5.1 and IIS 6.0 is provided by FastCGI ISAPI extension which is available as an independent download. On IIS 7.0 and beyond, FastCGI functionality is provided by IIS FastCGI module which comes with the operating system. These components use different configuration stores to store the settings that affect their behavior. FastCGI ISAPI uses an INI file named fcgiext.ini as its configuration store whereas FastCGI module keeps configuration in applicationHost.config in xml format with rest of IIS configuration. Before, migrating from IIS6 to IIS7 involved migrating fcgiext.ini configuration to FastCGI module manually as there was no automated way to do that. MSDeploy only had functionality to migrate metabase configuration but because FastCGI ISAPI configuration is kept separately in an INI file, that wasn’t possible.

Solution

MSDeploy v1 RTW which is released today include a new provider named fcgiextConfig to automate task of migrating FastCGI ISAPI INI configuration to FastCGI module section. FcgiextConfig provider accepts a path which can be “APPHOST” or ”INI”. When path “APPHOST” is specified, configuration from system.webServer/fastCgi section in applicationHost.config is read. Path “APPHOST” should only be used on systems running FastCGI module (i.e. IIS7 and beyond). When path “INI” is specified, this provider reads the configuration from file “%windir%\system32\inetsrv\fcgiext.ini” and produce xml which looks like FastCGI module configuration. Once INI settings are mapped to produce the xml, msdeploy engine can compare configuration of FastCGI ISAPI with FastCGI module and make changes to FastCGI module configuration as required. Again, path “INI” can only be used on a machine which is running FastCGI ISAPI.

Examples

Dump command to dump INI settings looks like following.
        msdeploy –verb:dump –source:fcgiExtConfig=ini –xml
        msdeploy –verb:dump –source:fcgiExtConfig=apphost –xml

Sync command to move INI settings to FastCGI module section is following.
        msdeploy –verb:sync –source:fcgiExtConfig=ini –dest:fcgiExtConfig=apphost -whatif

Details

  Here is how INI settings are mapped to system.webServer/fastCgi settings. For each entry   “<extension>:<optionalsiteid>=<sectionname>” under [Types] section of fcgiext.ini, we read the settings under section [<sectionname>]. If optional site id is present, we look for an entry for the same extension but without site id. If an entry is found, we use configuration under this entry as base set of settings for the site specific entry. So if “php=basephp” and “php:1=site1” entries are present in INI, settings under section [basephp] provide base values and then settings under section [site1] override base settings to generate configuration for “php:1” process pool. If a property is not present in the INI file, we assume the default value as assumed by FastCGI ISAPI extension. A FastCGI process pool entry is created for each INI entry with a valid ExePath. Various INI file settings are mapped to a FastCGI process pool as below.
  

fcgiext.ini configuration setting system.webServer/fastCgi/application property
ExePath fullPath
Arguments arguments
QueueLength queueLength
MaxInstances maxInstances
IdleTimeout idleTimeout
ActivityTimeout activityTimeout
RequestTimeout requestTimeout
InstanceMaxRequests instanceMaxRequests
FlushNamedPipe flushNamedPipe
Protocol protocol
RapidFailsPerMinute rapidFailsPerMinute
EnvironmentVars environmentVariables
ResponseBufferLimit Ignored
IgnoreExistingFiles Ignored
IgnoreDirectories Ignored
UnhealthyOnQueueFull Ignored


If the source version is FastCGI ISAPI 1.5, some additional properties get picked and mapped as below.
 

StderrMode stderrMode
MonitorChangesTo MonitorChangesTo
SignalBeforeTerminateSeconds signalBeforeTerminateSeconds


If FastCGI ISAPI version on source and FastCGI module version on destination are not compatible, fcgiextConfig provider will block the migration. Note that fcgiextConfig provider doesn’t take care of migrating the relevant IIS ScriptMaps. You can migrate ScriptMaps using a separate msdeploy migrate operation.

Hope this helps.
Kanwal

One thought on “Migrating FastCGI configuration from IIS 5.1/6.0 to IIS 7.0/7.5

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