<div dir="ltr">Hi Noel,<div><div class="gmail_extra"><br><div class="gmail_quote">On 22 October 2014 01:57, Noel Burton-Krahn <span dir="ltr"><<a href="mailto:noel@pistoncloud.com" target="_blank">noel@pistoncloud.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Hi Armando,<div><br></div><div>Sort of... but what happens when the second one dies? </div></div></blockquote><div><br></div><div>You mean, you lost both (all) agents? In this case, yes you'd need to resurrect the agents or move the networks to another available agent.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div>If one DHCP agent dies, I need to be able to start a new DHCP agent on another host and take over from it. As far as I can tell right now, when one DHCP agent dies, another doesn't take up the slack.</div></div></blockquote><div><br></div><div>I am not sure I fully understand the failure mode you are trying to address. The DHCP agents can work in an active-active configuration, so if you have N agents assigned per network, all of them should be able to address DHCP traffic. If this is not your experience, ie. one agent dies and DHCP is no longer served on the network by any other agent, then there might be some other problem going on.</div><div> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div> </div><div><br></div><div>I have the same problem wit L3 agents by the way, that's next on my list</div><div><br></div><div>--</div><div>Noel</div><div><br></div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 21, 2014 at 12:52 PM, Armando M. <span dir="ltr"><<a href="mailto:armamig@gmail.com" target="_blank">armamig@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">As far as I can tell when you specify:<div><br></div><div><span style="font-family:arial,sans-serif;font-size:13px">dhcp_agents_per_network = X > 1</span></div><div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">The server binds the network to all the agents (up to X), which means that you have multiple instances of dnsmasq serving dhcp requests at the same time. If one agent dies, there is no fail-over needed per se, as the other agent will continue to server dhcp requests unaffected.</span></div><div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><font face="arial, sans-serif">For instance, in my env I have </font><span style="font-family:arial,sans-serif;font-size:13px">dhcp_agents_per_network=2, so If I create a network, and list the agents serving the network I will see the following:</span></div><div>
<p><font face="courier new, monospace">neutron dhcp-agent-list-hosting-net test</font></p><p><span style="font-family:'courier new',monospace;font-size:x-small">+--------------------------------------+--------+----------------+-------+</span><br></p><p><font face="courier new, monospace" size="1">| id | host | admin_state_up | alive |</font></p><p><font face="courier new, monospace" size="1">+--------------------------------------+--------+----------------+-------+</font></p><p><font face="courier new, monospace" size="1">| 6dd09649-5e24-403b-9654-7aa0f69f04fb | host1 | True | :-) |</font></p><p><font face="courier new, monospace" size="1">| 7d47721a-2725-45f8-b7c4-2731cfabdb48 | host2 | True | :-) |</font></p><p>
</p><p><font face="courier new, monospace" size="1">+--------------------------------------+--------+----------------+-------+</font></p></div><div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">Isn't that what you're after?</span></div><div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">Cheers,</span></div><div><span style="font-family:arial,sans-serif;font-size:13px">Armando</span><br></div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On 21 October 2014 22:26, Noel Burton-Krahn <span dir="ltr"><<a href="mailto:noel@pistoncloud.com" target="_blank">noel@pistoncloud.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">We currently have a mechanism for restarting the DHCP agent on another node, but we'd like the new agent to take over all the old networks of the failed dhcp instance. Right now, since dhcp agents are distinguished by host, and the host has to match the host of the ovs agent, and the ovs agent's host has to be unique per node, the new dhcp agent is registered as a completely new agent and doesn't take over the failed agent's networks. I'm looking for a way to give the new agent the same roles as the previous one.<div><br></div><div>--</div><div>Noel</div><div><br></div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 21, 2014 at 12:12 AM, Kevin Benton <span dir="ltr"><<a href="mailto:blak111@gmail.com" target="_blank">blak111@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">No, unfortunately when the DHCP agent dies there isn't automatic rescheduling at the moment.</div><div class="gmail_extra"><div><div><br><div class="gmail_quote">On Mon, Oct 20, 2014 at 11:56 PM, Noel Burton-Krahn <span dir="ltr"><<a href="mailto:noel@pistoncloud.com" target="_blank">noel@pistoncloud.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div>Thanks for the pointer! </div><div><br></div><div>I like how the first google hit for this is:</div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px">Add details on dhcp_agents_per_network option for DHCP agent HA<br><div><a href="https://bugs.launchpad.net/openstack-manuals/+bug/1370934" target="_blank">https://bugs.launchpad.net/openstack-manuals/+bug/1370934</a></div><div><br></div></blockquote><div>:) Seems reasonable to set dhcp_agents_per_network > 1. What happens when a DHCP agent dies? Does the scheduler automatically bind another agent to that network?</div><div><br></div><div>Cheers,</div><div>--<br></div><div>Noel</div><div><br></div><div><br></div></div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 20, 2014 at 9:03 PM, Jian Wen <span dir="ltr"><<a href="mailto:wenjianhn@gmail.com" target="_blank">wenjianhn@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div>See dhcp_agents_per_network in neutron.conf.</div><div><br></div><a href="https://bugs.launchpad.net/neutron/+bug/1174132" target="_blank">https://bugs.launchpad.net/neutron/+bug/1174132</a><br><div class="gmail_extra"><br><div class="gmail_quote"><span>2014-10-21 6:47 GMT+08:00 Noel Burton-Krahn <span dir="ltr"><<a href="mailto:noel@pistoncloud.com" target="_blank">noel@pistoncloud.com</a>></span>:<br></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><div dir="ltr">I've been working on failover for dhcp and L3 agents. I see that in [1], multiple dhcp agents can host the same network. However, it looks like I have to manually assign networks to multiple dhcp agents, which won't work. Shouldn't multiple dhcp agents automatically fail over?<div><br></div><div>[1] <a href="http://docs.openstack.org/trunk/config-reference/content/multi_agent_demo_configuration.html" target="_blank">http://docs.openstack.org/trunk/config-reference/content/multi_agent_demo_configuration.html</a></div><div><br></div><div><br></div></div>
<br></span>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><span><font color="#888888"><br><br clear="all"><div><br></div>-- <br>Best,<br><br>Jian<br>
</font></span></div></div>
<br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br></div>
</div></div><br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br><br clear="all"><div><br></div>-- <br></div></div><span><font color="#888888"><div>Kevin Benton</div>
</font></span></div>
<br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br></div>
</div></div><br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br></div>
</div></div><br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br></div>
</div></div><br>_______________________________________________<br>
OpenStack-dev mailing list<br>
<a href="mailto:OpenStack-dev@lists.openstack.org" target="_blank">OpenStack-dev@lists.openstack.org</a><br>
<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
<br></blockquote></div><br></div></div></div>