[Linux-cluster] RedHat Cluster Suite cluster resource management

[linux-cluster at merctech.com]

In the message dated: Fri, 14 Nov 2008 17:02:03 EST,
Lon Hohberger  used the subject line
	<Re: [Linux-cluster] RedHat Cluster Suite cluster resource management>
and wrote:

=> On Thu, 2008-11-13 at 15:14 +0100, Mauro Casiraghi wrote:
=> > I had created this cluster configuration with Redhat Cluster Suite 
=> >  
=> > I Have one Service Group with the follow resources
=> >  
=> > Service Group Name : WEB
=> >  
=> > Resources of the service group:
=> >  
=> > 1) IP_ADRESS
=> > 2) APACHE
=> >  
=> > The resource dependency are:
=> >  
=> > The Apache resource is dependent of ip_adress
=> 
=> Assuming you are running RHEL 5.3 beta or RHEL5.2 (or using stable2
=> branch of linux-cluster):
=> 
=> <rm> 
=>   <service name="apache" depend="service:ip_address">
=>     <script name="my_apache_script" ... />
=>   </service>
=>   <service name="ip_address" >
=>     <ip adress="my_ip_address"/>
=>   </service>
=> </rm>
=> 
=> [NOTE: that because rgmanager is an 'event-action' (not 'dependency
=> modeling') between services, disabling ip_address will cause a
=> successive transition of apache, not a preceding transition.]

Can you please give more information about your "NOTE" or provide some
references? I've worked with other HA clusters (Sun, Veritas, HP), but it's 
still unclear to me how to manage what seem to be basic service hierarchies
in RHCS.

Does the snippet above also mean that the apache service will start only if the 
IP address is available?

I've got a 2-node cluster providing NFS services, using the Managed Virtual IP
model described in the RHCS NFS Cookbook. The basic NFS service works fine.
However, I want to make sure that the NFS service (ie., the VIP) depends on the
presence of the GFS storage resource.

For example:
	the VIP used for NFS export of "/data" depends on
	the GFS directory "/data" that will be exported via NFS...the cluster
	shouldn't activate the VIP on a node that doesn't have "/data" mounted

However, if the VIP transition from one cluster node to the other, that doesn't 
imply that the GFS partition should be unmounted from the node that doesn't 
have the service.

Ideally, I'd like a configuration that specifies that the GFS partition is a
prerequisite for the NFS service, but is not a resource controlled by the NFS 
service. Is this possible with RHCS?

Thanks,

Mark

=> 
=> OR..........
=> 
=> <rm> 
=>   <service name="apache_service">
=>     <script name="my_apache_script" ... />
=>     <ip adress="my_ip_address"/>
=>   </service>
=> </rm>
=> 
=> Start the service, then do:
=> 
=>   'clusvcadm -Z apache_service'
=> 
=> ... then do whatever you want, then ...
=>   
=>   'clusvcadm -U apache_service'
=> 
=> [NOTE: 5.3 beta or STABLE2 branch ONLY!]
=> 
=> -- Lon
=> 
=> 
=> --
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