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From Kanak Biscuitwala <kbiscuitw...@linkedin.com>
Subject Re: Recommended approach to redefining state model
Date Mon, 04 Nov 2013 21:29:11 GMT
Hi Santiago,

You're correct in your assumption that only controllers directly read your state model, but
I think you also need to be aware of your participants. I think in your case, the states in
your new state model comprise a superset of the old one, so your approach should be fine (as
long as there's a way for your current states to reach your new ones).

Ordinarily it's safer to first disable your instances (so that they go into the initial state)
and then enable once the state model is updated (or even drop your instances and re-add them).

Kanak

From: Santiago Perez <santip@santip.com.ar<mailto:santip@santip.com.ar>>
Reply-To: "user@helix.incubator.apache.org<mailto:user@helix.incubator.apache.org>"
<user@helix.incubator.apache.org<mailto:user@helix.incubator.apache.org>>
Date: Monday, November 4, 2013 2:14 PM
To: "dev@helix.incubator.apache.org<mailto:dev@helix.incubator.apache.org>" <dev@helix.incubator.apache.org<mailto:dev@helix.incubator.apache.org>>,
"user@helix.incubator.apache.org<mailto:user@helix.incubator.apache.org>" <user@helix.incubator.apache.org<mailto:user@helix.incubator.apache.org>>
Subject: Recommended approach to redefining state model

Hi,

I need to redefine a state model on a live cluster and would like to know the recommended
(safe) way to do so.

My current plan was to do the fololwing:

1) Stop all controllers
2) Remove the node from STATEMODELDEFS
3) Run code that will rewrite the state model
4) Start controllers again

I'm assuming that only controllers load the state models, but I may be mistaken.

Please advice.

Thanks,
Santiago

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