On 03/16/2015 01:13 PM, Georgios Dimitrakakis wrote:
Hi again! I 've used tcpdump to capture the ARP requests.
This is what I get for ARP requests coming from "send_arp_for_ha" by
OpenStack:
04:56:25.995860 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 tell 15.12.11.226, length 46
04:56:25.995894 ARP, Ethernet (len 6), IPv4 (len 4), Reply 15.12.11.34
is-at 70:e2:84:0b:59:a0 (oui Unknown), length 28
04:56:31.889363 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.228 tell 15.12.11.227, length 46
04:56:32.581746 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.228 tell 15.12.11.227, length 46
04:56:33.482519 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.228 tell 15.12.11.227, length 46
04:56:34.382775 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.228 tell 15.12.11.227, length 46
04:56:35.082594 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.228 tell 15.12.11.227, length 46
04:56:47.121268 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.240 tell 15.12.11.226, length 46
04:56:47.699135 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 tell 15.12.11.227, length 46
04:56:47.699162 ARP, Ethernet (len 6), IPv4 (len 4), Reply 15.12.11.34
is-at 70:e2:84:0b:59:a0 (oui Unknown), length 28
I'm guessing none of that was broadcast. Which could be a large
difference between that and what you did manually.
You didn't by any chance happen to capture the packets to a binary file
so you can re-read the .pcap with the -e option (show ethernet info) and
perhaps -v ?
rick jones
If I manually try with the
"arping -c 10 -U -I eth0 15.12.11.34" command, tcpdump logs the following:
04:57:15.907743 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:16.907843 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:17.907943 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:18.908068 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:19.908165 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:20.908288 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:21.908375 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:22.908551 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:23.908652 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
04:57:24.908846 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has
15.12.11.34 (Broadcast) tell 15.12.11.34, length 28
The IP addresses ending at *.226 and *.227 are according to the
datacenter spare gateway addresses.
Is it possible that OpenStack ARP requests is just to verify if the IP
address is known and by which machine
rather than sending update requests???
Kind regards,
George
I will try to see if I can get anything from the logs.
If someone else can come to a better suggestion I am all ears.
Not having full access to the DataCenter and the underlying equipment
has caused me enough headaches so far :-(
Best,
George
On 03/14/2015 03:32 PM, Georgios Dimitrakakis wrote:
Hello again Rick!
On 03/13/2015 06:25 PM, Georgios Dimitrakakis wrote:
If I do an :
arping -U -I etho x.x.x.x
where x.x.x.x is the IP address.
I can almost immediately access them outside of the subnet!
I had forgotten that, Still is that the very same set of options the
OpenStack code uses?
I am not aware about that and I would like to know!
What does Openstack does and how ofted does it send the gratuitous ARP
request?
I don't recall off the top of my head (perhaps someone else does) -
and my corner of the world is Neutron rather than Nova networking. If
there is much logging enabled I suspect you could see the commands in
the logs. Certainly Neutron is very "chatty" when it comes to logging
things.
Do you mean that OpenStack is sending a gratuitous ARP for all
and the router is ignoring them unless it is for a specific IP
address?
If this is the case is there anything I can do?
I will second the suggestion of getting a packet trace to see just
what sort of ARP traffic the compute node(s) send and then compare
that with the documentation for your router.
rick
I will try to see if I can get anything but the problem is that the
datacenter hosting the facility is in Japan and there is a huge gap
communicating with them (actually there is no communication).
If I could only find out what does the router accept would be very
nice :-)
Nothing beats being able to see the blinking lights :)
rick
_______________________________________________
Mailing list:
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
Post to : openstack@lists.openstack.org
Unsubscribe :
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
_______________________________________________
Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
Post to : openstack@lists.openstack.org
Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
_______________________________________________
Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
Post to : openstack@lists.openstack.org
Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
