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[Linux-cluster] help wanted configuring services

Is it possible to set up a hierarchy of services, in the same way that a 
service is made up of individual resources?

I'm trying to set up a clustered web server using RHCS 5 on CentOS 5.2, with 
the latest versions from the "upstream provider's" production release.

The cluster provides several web applications, each of which has it's own
resources that Apache doesn't need to know about directly. Each application
relies on Apache as a presentation layer. I don't want to make the individual
applications' dependencies separate resources within a single "Apache" service,
because that makes management difficult.

For example, is it possible to create a structure like:

	Service:	Apache
		Private Resource:	IP address
		Private Resource:	GFS Vol1

		Shared Service:	Wiki
		Shared Service:	SVN
		Shared Service:	Calendar

	Service:	Wiki
		Private Resource:	GFS Vol2
		Private Resource:	MySQL "wiki" instance
	Service:	SVN
		Private Resource:	MySQL "svn" instance
		Private Resource:	GFS Vol3
	Service:	Calendar
			(no resources beyond apache)

Note that resources like "GFS Vol2" and "MySQL wiki instance" are assigned
to the "Wiki" service, not directly to the "Apache" service. The Apache
service sees "Wiki" as a resource.

With this kind of structure, I could administratively disable the "Wiki" service
without causing the other web applications to restart or relocate. However, if a
resource that the Wiki requires fails on the active web server (for example, GFS
Vol 2), the the standard failover policy would apply...the Wiki service would
restart and if that is unsuccessful, then the Apache service (and it's
dependencies--Wiki, SVN, Calendar, IP address, GFS Vol1) would relocate.

Is there any way to set up this kind of structure with RHCS?



Mark Bergman    


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