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<div>Just a update; since I'm the one who recently did a lot of the openstack adjustments in cloud-init.</div>
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<div>So this one line is part of the ipv4 requirement:</div>
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<div><a href="http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceOpenStack.py#L30">http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceOpenStack.py#L30</a></div>
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<div>It though can be overriden either by user-data or by static-configuration data that resides inside the image.</div>
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<div>This is the line of code that does this:</div>
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<div><a href="http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceOpenStack.py#L77">http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceOpenStack.py#L77</a></div>
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<div>This means that the image builder can set cloud-init config list 'metadata_urls' to be a ipv6 format (if they want).</div>
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<div>The underlying requests library (as long as it supports ipv6) should be happy using this (hopefully there aren't any other bugs that hinder its usage).</div>
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<div>Btw, for the curios, that datasource inherits from the same base class as <a href="http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceConfigDrive.py">
http://bazaar.launchpad.net/~cloud-init-dev/cloud-init/trunk/view/head:/cloudinit/sources/DataSourceConfigDrive.py</a> (a mixin is used) so the config drive code and the openstack metadata reading code actually use the same base code (which was a change that
I did that I thought was neat) and only change how they read the data (either from urls or from a filesystem). </div>
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<span style="font-weight:bold">From: </span><CARVER>, PAUL <<a href="mailto:pc2929@att.com">pc2929@att.com</a>><br>
<span style="font-weight:bold">Reply-To: </span>"OpenStack Development Mailing List (not for usage questions)" <<a href="mailto:openstack-dev@lists.openstack.org">openstack-dev@lists.openstack.org</a>><br>
<span style="font-weight:bold">Date: </span>Monday, July 7, 2014 at 11:26 AM<br>
<span style="font-weight:bold">To: </span>"OpenStack Development Mailing List (not for usage questions)" <<a href="mailto:openstack-dev@lists.openstack.org">openstack-dev@lists.openstack.org</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [openstack-dev] [Neutron] cloud-init IPv6 support<br>
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<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 10pt; font-family: Tahoma, sans-serif;">Andrew Mann wrote:</span></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>What's the use case for an IPv6 endpoint? This service is just for instance metadata,<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">></span>so as long as a requirement to support IPv4 is in place, using solely an IPv4 endpoint<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">></span>avoids a number of complexities:<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">The obvious use case would be deprecation of IPv4, but the question is when. Should I<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">expect to be able to run a VM without IPv4 in 2014 or is IPv4 mandatory for all VMs?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">What about the year 2020 or 2050 or 2100? Do we ever reach a point where we can turn<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">off IPv4 or will we need IPv4 for eternity?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">Right now it seems that we need IPv4 because cloud-init itself doesn’t appear to support<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">IPv6 as a datasource. I’m going by this documentation<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><a href="http://cloudinit.readthedocs.org/en/latest/topics/datasources.html#what-is-a-datasource">http://cloudinit.readthedocs.org/en/latest/topics/datasources.html#what-is-a-datasource</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">where the “magic ip” of 169.254.169.254 is referenced as well as some non-IP mechanisms.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">It wouldn’t be sufficient for OpenStack to support an IPv6 metadata address as long as<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">most tenants are likely to be using a version of cloud-init that doesn’t know about IPv6<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">so step one would be to find out whether the maintainer of cloud-init is open to the<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">idea of IPv4-less clouds.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">If so, then picking a link local IPv6 address seems like the obvious thing to do and the<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">update to Neutron should be pretty trivial. There are a few references to that<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">“magic ip”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><a href="https://github.com/openstack/neutron/search?p=2&q=169.254.169.254&ref=cmdform">https://github.com/openstack/neutron/search?p=2&q=169.254.169.254&ref=cmdform</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);">but the main one is the iptables redirect rule in the L3 agent:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><a href="https://github.com/openstack/neutron/blob/master/neutron/agent/l3_agent.py#L684">https://github.com/openstack/neutron/blob/master/neutron/agent/l3_agent.py#L684</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
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