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2013-06-14 20:15:55 -0500 answered a question VMs / stacks described in a template created and deployed in parallel or serially?

Thanks Zane Bitter, that solved my question.

2013-06-14 20:15:31 -0500 answered a question VMs / stacks described in a template created and deployed in parallel or serially?

Hi Zane,

Thank you very much for the clarification and pointers to the code!

Thanks, LN

2013-06-14 14:41:08 -0500 answered a question VMs / stacks described in a template created and deployed in parallel or serially?

Hi Zane,

Thanks very much for the detailed reply.

I have a follow up question regarding when and how Heat determines a dependence is satisfied and hence starts the creation of the dependent resource.

Consider a template that creates two VMs, say vmA and vmB, with the following properties:

-- vmA needs the IP address of vmB and uses a Ref to get that

-- vmB has UserData that installs a lot of applications, after the VM is created.

Now, I assume that Heat will first create vmB and then create vmA. When does the creation of vmA start? After vmB (the base vm) is created, i.e, Nova has started vmB? or After Nova has started vmB AND all its UserData scripts are executed?

I am also interested in looking at the

  1. code that analyzes the template for Ref, Fn::GetAtt and builds the dependence graph (I am assuming an explicit dependence graph is built)

  2. code that uses the dependence graph to enforce the order of VM creation.

Can you please point me to these parts of the code?

Once again, thanks very much for your time and I greatly appreciate the help.

LN

2013-06-14 14:10:58 -0500 answered a question VMs / stacks described in a template created and deployed in parallel or serially?

Thanks Zane Bitter, that solved my question.

2013-06-13 21:16:15 -0500 asked a question VMs / stacks described in a template created and deployed in parallel or serially?

Hi,

I am interested in understanding how Heat deploys a template that specifies multiple VMs. For example, consider a template that creates 1 apache vm, 1 tomcat vm, and 1 mysql vm. Will Heat start creating and deploying these three VMs in parallel (i.e., concurrently) or will do it serially (in some order)?

I am also interested in Heat's VM creation scheme, when the template has multiple VMs and there are dependencies between them. For example, consider a dependency between the tomcat vm and the mysql vm, in the above scenario. With such dependencies, will Heat create the VMs in parallel or serially?

I would greatly appreciate any info / pointers (even to the right section of Heat code :-) )

Thanks for your time, LN