[Openstack] [openstack-dev] [qa] How to troubleshoot why a VM at Compute node won't response to ARP request from Neutron router

Shashank Hegde hegde.shashank at gmail.com
Sun Oct 12 17:26:08 UTC 2014


Hi Danny,

You can ssh into your compute node with X forwarding:
ssh -X user at compute

You can then attach to the VM's console using the command:
vncviewer :<display-number>

You can find the display number using the command:
ps aux | grep kvm
Look for vnc there. Its of the form 127.0.0.1:<display-number>

~ Shashank

On Sun, Oct 12, 2014 at 10:17 AM, Danny Choi (dannchoi) <dannchoi at cisco.com>
wrote:

>  I do have security rule configured to allow ICMP.
>
>  localadmin at qa4:~/devstack$ nova secgroup-list-rules default
>
> +-------------+-----------+---------+-----------+--------------+
>
> | IP Protocol | From Port | To Port | IP Range  | Source Group |
>
> +-------------+-----------+---------+-----------+--------------+
>
> | tcp         | 22        | 22      | 0.0.0.0/0 |              |
>
> |             |           |         |           | default      |
>
> |             |           |         |           | default      |
>
> | icmp        | -1        | -1      | 0.0.0.0/0 |              |
>
> +-------------+-----------+---------+-----------+———————+
>
>
>  Danny
>
>   From: Remo Mattei <remo at italy1.com>
> Date: Sunday, October 12, 2014 at 1:00 PM
> To: Danny Choi <dannchoi at cisco.com>
> Cc: "openstack at lists.openstack.org" <openstack at lists.openstack.org>, "
> openstack-dev at lists.openstack.org" <openstack-dev at lists.openstack.org>
> Subject: Re: [Openstack] [qa] How to troubleshoot why a VM at Compute
> node won't response to ARP request from Neutron router
>
>   By default icmp is not allowed
>
> Inviato da iPhone ()
>
> Il giorno 12/ott/2014, alle ore 09:25, Danny Choi (dannchoi) <
> dannchoi at cisco.com> ha scritto:
>
>   Hi,
>
>  Using devstack to deploy OpenStack, I have Controller + Network running
> at one physical node and Compute at a separate node.
>
>  I launched a VM at the Compute node with a private address 10.0.0.2
> (Neutron router interface is 10.0.0.1).
>
>  At the Controller node, in the qrouter namespace, I could not ping the
> VM private address 10.0.0.2.
>
>  At the Compute node, tcpdump of the tap interface indicated ARP requests
> were received.
>
>  However, it did not show any ARP response.
>
>  My understanding is that the VM’s virtual interface is directly
> connected to this tap interface.  Since the VM is unreachable, I cannot
> launch its console to see if the ARP requests are received at the virtual
> interface.
>
>  Any suggestions on how to troubleshoot this?
>
>  localadmin at qa4:~/devstack$ nova show vm1
>
>
> +--------------------------------------+----------------------------------------------------------------+
>
> | Property                             | Value
>                               |
>
>
> +--------------------------------------+----------------------------------------------------------------+
>
> | OS-DCF:diskConfig                    | MANUAL
>                               |
>
> | OS-EXT-AZ:availability_zone          | nova
>                               |
>
> | OS-EXT-STS:power_state               | 1
>                               |
>
> | OS-EXT-STS:task_state                | -
>                               |
>
> | OS-EXT-STS:vm_state                  | active
>                               |
>
> | OS-SRV-USG:launched_at               | 2014-10-12T14:25:15.000000
>                               |
>
> | OS-SRV-USG:terminated_at             | -
>                               |
>
> | accessIPv4                           |
>                               |
>
> | accessIPv6                           |
>                               |
>
> | config_drive                         |
>                               |
>
> | created                              | 2014-10-12T14:23:30Z
>                               |
>
> | flavor                               | m1.tiny (1)
>                               |
>
> | hostId                               |
> 00ac69883737ebd290ad4f38cae979a6e268902333261ba6bfbade44       |
>
> | id                                   |
> 04b5a345-cadf-4dee-9209-5bcf589b6a3c                           |
>
> | image                                | cirros-0.3.2-x86_64-uec
> (14a55982-a093-4850-80c8-7b2ae3a7eaba) |
>
> | key_name                             | -
>                               |
>
> | metadata                             | {}
>                               |
>
> | name                                 | vm1
>                               |
>
> | os-extended-volumes:volumes_attached | []
>                               |
>
> | private network                      | 10.0.0.2, 172.29.173.5
>                               |
>
> | progress                             | 0
>                               |
>
> | security_groups                      | default
>                               |
>
> | status                               | ACTIVE
>                               |
>
> | tenant_id                            | 90058797dddc49efae4d1f45aa5ab982
>                               |
>
> | updated                              | 2014-10-12T14:23:39Z
>                               |
>
> | user_id                              | 5ab6344540974a1fbda5b539778ebe35
>                               |
>
>
> +--------------------------------------+----------------------------------------------------------------+
>
> localadmin at qa4:~/devstack$
>
> localadmin at qa4:~/devstack$ ip netns
>
> qdhcp-f55f0683-830f-4523-82cb-46d638f91d47
>
> qrouter-62aecbdd-d58d-4b33-a743-b16ca38544c5
>
> localadmin at qa4:~/devstack$
>
> localadmin at qa4:~/devstack$
>
> localadmin at qa4:~/devstack$ sudo ip netns exec
> qrouter-62aecbdd-d58d-4b33-a743-b16ca38544c5 ping 10.0.0.2
>
> PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
>
> From 10.0.0.1 icmp_seq=1 Destination Host Unreachable
>
> From 10.0.0.1 icmp_seq=2 Destination Host Unreachable
>
> From 10.0.0.1 icmp_seq=3 Destination Host Unreachable
>
> From 10.0.0.1 icmp_seq=4 Destination Host Unreachable
>
> From 10.0.0.1 icmp_seq=5 Destination Host Unreachable
>
> From 10.0.0.1 icmp_seq=6 Destination Host Unreachable
>
>
>
>  localadmin at qa5:~/devstack$ sudo tcpdump -i tapade47169-57
>
> tcpdump: WARNING: tapade47169-57: no IPv4 address assigned
>
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>
> listening on tapade47169-57, link-type EN10MB (Ethernet), capture size
> 65535 bytes
>
> 11:58:30.042379 ARP, Request who-has 10.0.0.2 tell 10.0.0.1, length 42
>
> 11:58:31.041840 ARP, Request who-has 10.0.0.2 tell 10.0.0.1, length 42
>
> 11:58:32.041848 ARP, Request who-has 10.0.0.2 tell 10.0.0.1, length 42
>
> 11:58:33.044212 ARP, Request who-has 10.0.0.2 tell 10.0.0.1, length 42
>
> 11:58:34.041866 ARP, Request who-has 10.0.0.2 tell 10.0.0.1, length 42
>
>
>  Thanks,
> Danny
> !DSPAM:1,543aaefc201211675819574!
>
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