Re: Fwd: [Smartfrog-support] sfStart() timeout

Olivier Pernet wrote:

> 
> While I was at CERN this summer, we ran into the same problem when
> deploying Xen virtual machines.
> What I did was a bit different : I started a thread pinging the new
> virtual machine every N seconds, reporting to a set of Observers when
> the VM was brought up, or died.
> http://smartdomains.svn.sourceforge.net/viewvc/smartdomains/trunk/src/ch/cern/openlab/smartdomains/DomainMonitoringThread.java?revision=71&view=markup
> 
> Then, in the XenDomainManager component (the SmartFrog component), the
> sfStart() method waits to be notified of the VM creation :
> http://smartdomains.svn.sourceforge.net/viewvc/smartdomains/trunk/src/ch/cern/openlab/smartdomains/XenDomainManager.java?revision=84&view=markup
> 
> All in all it's pretty simple.
> 
> Cheers
> 

ok, so if we were to have a Condition interface, you'd have a new 
XenNodeUp condition that could be tested and integrated with workflow?

I like the idea of having a component that could observe one or more 
conditions and get notified when any of them changed state. It would be 
a workflow component that would use the condition as a trigger


something extends Trigger {
    condition extends XenNodeUp { hosts [ .. ]; }

    action extends Sequence { ... }


}

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