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Cannot Ping VMs

asked 2015-10-27 14:24:56 -0500

stindell gravatar image

updated 2015-10-27 14:33:10 -0500

I have 3 physical hosts:




Each has only 1 NIC.

OpenStack Kilo, KVM.

I have setup the keystone, glance, and nova services. I have configured neutron with openvswitch and gre tunnels. Yesterday I setup neutron services, configured my ml2 plugin files, and started up an instance. I was able to create networks/subnets, and a router attached to the appropriate networks. I can ping the router. The router and dhcp server can ping each other. But they cannot ping my VMs. I assume it's a problem with the br-int and br-tun between network <-> compute nodes.

Here are my ml2.ini configs, ovs-vsctl show output, and ovs-ofcs dump-flows output:

Here's my VM: | 2b135380-6218-43da-9fe2-08d8e5ee58c7 | demo-instance1 | ACTIVE | - | Running | demo-net=, |

In the virtual machine console log, it shows that it is not getting a DHCP lease at all. Starting network... udhcpc (v1.20.1) started Sending discover... Sending discover... Sending discover... Usage: /sbin/cirros-dhcpc <up|down> No lease, failing WARN: /etc/rc3.d/S40-network failed

IPTables is disabled on all hosts.

There is no br-tun interface to tcpdump on the compute node. tcpdump on the br-int interface qvo1351e4f4-d2 shows nothing when I try to ping from network host -> VM or from qrouter -> VM.

Any tips? Any idea where my network setup has gone wrong?

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Installation guide clearly tells we need to maintain two interface like eth0 & eth1. eth0 for management network and eth1 for tunnel network. i hope you need to do the same thing.

To debug and understand you can follow - ( gravatar ( 2015-10-27 22:49:55 -0500 )edit

I only have one NIC per host. What do you suggest?

stindell gravatar imagestindell ( 2015-10-28 13:12:24 -0500 )edit

well, that's tricky then , we need a workaround , I have done this for vlan based network where i have created a bridge (eg- br-eth) on the NIC and provided the Management IP to that bridge. So eventually , you will have the bridge to connect to br-int and also an IP for management network. gravatar ( 2015-10-28 23:30:39 -0500 )edit

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answered 2016-12-28 18:22:38 -0500

tze gravatar image

First of all i think Some versions of Cirros Image has a bug with DHCP leases. Check if your Image version hasn't bug on DHCP lease. Secondly i think your gre setup is ok. On your both nodes (Network and compute) you have from one internal port so, you can add a temporarly ip (other subnet of that you already used) on both interfaces (Network node/br-tun, Compute node/br-tun) and check if they can ping each other. If your ping works, your gre tunnel is correct. I need more details to suggest you something else, for example the neutron networks config, and subnet confg. You Dhcp agent works fine(openstack network agent list)? On network node the network namespace created correct?

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Asked: 2015-10-27 14:24:56 -0500

Seen: 548 times

Last updated: Dec 28 '16