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<p>Hi Praveen,<br>
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<p>The docs you referred to in the plugin guide is for the resource property attributes - they have nothing to do with parameters. This is an important distinction because there is also an "immutable" parameter attribute.<br>
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<p>The "immutable" property attribute was added because an equivalent to AWS' "Updates are not supported" functionality was needed:<br>
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<p><a href="https://specs.openstack.org/openstack/heat-specs/specs/juno/implement-aws-updates-not-supported.html#aws-cloudformation">https://specs.openstack.org/openstack/heat-specs/specs/juno/implement-aws-updates-not-supported.html#aws-cloudformation</a><br>
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<p>Jason<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Praveen Yalagandula <ypraveen@avinetworks.com><br>
<b>Sent:</b> Monday, May 2, 2016 11:55 AM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> [openstack-dev] [heat] update_allowed vs. immutable</font>
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<div dir="ltr">What is the difference between "update_allowed" and "immutable" parameters for a property? According to the plugin guide at
<div><a href="http://docs.openstack.org/developer/heat/developing_guides/pluginguide.html">http://docs.openstack.org/developer/heat/developing_guides/pluginguide.html</a>:</div>
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<div>update_allowed:</div>
<div>True if an existing resource can be updated, False means update is accomplished by delete and re-create. Default is False.</div>
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<div>immutable:</div>
<div>True means updates are not supported, resource update will fail on every change of this property. False otherwise. Default is False.</div>
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<div>Since any resource can be deleted and then re-created, it seems "update_allowed" is the right parameter to define. Why do we need "immutable"?</div>
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<div>Thanks,<br>
Praveen Yalagandula</div>
<div>Avi Networks</div>
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