Does Heat allow for in place upgrades of instances

asked 2014-02-11 19:06:52 -0500

grahamhayes gravatar image

Does heat allow you to upgrade instances to newer versions, without destroying the instance?

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answered 2014-03-04 22:03:46 -0500

Steve Baker gravatar image

You'll need to be more specific about what properties of the server you want to change during update. The template guide will tell you which properties will support updating without replacement:

Also OS::Nova::Server has a property image_update_policy which lets you choose what happens when the image is updated (replace or rebuild)

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Hello Steve,

Could you please explain what is the difference between "replace" and "rebuild" for OS::Nova:Server resource when executing "heat stack-update..."?

Highly appreciated your reply!

Regards, Casper

casperl gravatar imagecasperl ( 2014-05-11 04:26:56 -0500 )edit

answered 2014-02-18 10:11:57 -0500

zaneb gravatar image

updated 2014-02-18 10:14:07 -0500

Whether a stack update causes a resource to be replaced depends on which resource type it is, what you change, and to some extent what version of Heat you are running.

For a Nova server, and most other resources, you can always update the metadata without replacing the server.

The os_collect_config tool can be used in-instance to poll for metadata changes, and the new software deployment features being introduced for Icehouse will hopefully provide an even simpler way to do exactly what you want - push info to a config management tool.

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answered 2014-02-12 03:04:35 -0500

vladber gravatar image

Per AWS implementation of CloudFormations. there are 3 ways to implement an update. - Update with no interruption - Update with some interruption - Update requires replacement

However when using heat, the only stack-update method requires replacement. "UpdateStack Status

Initial support for UpdateStack has been added for heat v5. Currently only implementation of the "Update requires replacement" strategy, as the default strategy for all resources/properties."

In other words , when you run heat-update an old instance will be rebuilt .


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Thats what I thought. I was looking at using the Heat Metadata service to provide info to a config management tool (salt, puppet etc) that could update boxes, without having to replace the image (and avoiding the issue above)

grahamhayes gravatar imagegrahamhayes ( 2014-02-12 09:15:08 -0500 )edit

Heat v5 was released 18 months ago; this information is thoroughly out of date.

zaneb gravatar imagezaneb ( 2014-02-18 10:12:34 -0500 )edit

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Asked: 2014-02-11 19:06:52 -0500

Seen: 1,968 times

Last updated: Mar 04 '14