[Openstack] Open vSwitch not working as expected...?

Aaron Knister aaron.knister at gmail.com
Fri Apr 25 19:15:28 UTC 2014


Can you send the output of ovs-vsctl show from both compute and network nodes?

Sent from my iPhone

> On Apr 25, 2014, at 2:23 PM, Erich Weiler <weiler at soe.ucsc.edu> wrote:
> 
> Hi Y'all,
> 
> I recently began rebuilding my OpenStack installation under the latest icehouse release, and everything is almost working, but I'm having issues with Open vSwitch, at least on the compute nodes.
> 
> I'm use the ML2 plugin and VLAN tenant isolation.  I have this in my /etc/neutron/plugin.ini file
> 
> ----------
> [ovs]
> bridge_mappings = physnet1:br-eth1
> 
> [ml2]
> type_drivers = vlan
> tenant_network_types = vlan
> mechanism_drivers  = openvswitch
> 
> # Example: mechanism_drivers = linuxbridge,brocade
> 
> [ml2_type_flat]
> 
> [ml2_type_vlan]
> network_vlan_ranges = physnet1:200:209
> ----------
> 
> My switchports that the nodes connect to are configured as trunks, allowing VLANs 200-209 to flow over them.
> 
> My network that the VMs should be connecting to is:
> 
> # neutron net-show cbse-net
> +---------------------------+--------------------------------------+
> | Field                     | Value                                |
> +---------------------------+--------------------------------------+
> | admin_state_up            | True                                 |
> | id                        | 23028b15-fb12-4a9f-9fba-02f165a52d44 |
> | name                      | cbse-net                             |
> | provider:network_type     | vlan                                 |
> | provider:physical_network | physnet1                             |
> | provider:segmentation_id  | 200                                  |
> | router:external           | False                                |
> | shared                    | False                                |
> | status                    | ACTIVE                               |
> | subnets                   | dd25433a-b21d-475d-91e4-156b00f25047 |
> | tenant_id                 | 7c1980078e044cb08250f628cbe73d29     |
> +---------------------------+--------------------------------------+
> 
> # neutron subnet-show dd25433a-b21d-475d-91e4-156b00f25047
> +------------------+--------------------------------------------------+
> | Field            | Value                                            |
> +------------------+--------------------------------------------------+
> | allocation_pools | {"start": "10.200.0.2", "end": "10.200.255.254"} |
> | cidr             | 10.200.0.0/16                                    |
> | dns_nameservers  | 128.114.48.44                                    |
> | enable_dhcp      | True                                             |
> | gateway_ip       | 10.200.0.1                                       |
> | host_routes      |                                                  |
> | id               | dd25433a-b21d-475d-91e4-156b00f25047             |
> | ip_version       | 4                                                |
> | name             |                                                  |
> | network_id       | 23028b15-fb12-4a9f-9fba-02f165a52d44             |
> | tenant_id        | 7c1980078e044cb08250f628cbe73d29                 |
> +------------------+--------------------------------------------------+
> 
> So those VMs on that network should send packets that would be tagged with VLAN 200.
> 
> I launch an instance, then look at the compute node with the instance on it.  It doesn't get a DHCP address, so it can't talk to the neutron node with the dnsmasq server running on it.  I configure the VM's interface to be a static IP on VLAN200, 10.200.0.30, and netmask 255.255.0.0.  I have another node set up on VLAN 200 on my switch to test with (10.200.0.50) that is a real bare-metal server.
> 
> I can't ping my bare-metal server.  I see the packets getting to eth1 on my compute node, but stopping there.  Then I figure out that the packets are *not being tagged* for VLAN 200 as they leave the compute node!!  So the switch is dropping them.    As a test I configure the switchport with "native vlan 200", and voila, the ping works.
> 
> So, Open vSwitch is not getting that it needs to tag the packets for VLAN 200.  A little diagnostics on the compute node:
> 
> ovs-ofctl dump-flows br-int
> NXST_FLOW reply (xid=0x4):
> cookie=0x0, duration=966.803s, table=0, n_packets=0, n_bytes=0, idle_age=966, priority=0 actions=NORMAL
> 
> Shouldn't that show some VLAN tagging?
> 
> and a tcpdump on eth1 on the compute node:
> 
> # tcpdump -e -n -vv -i eth1 | grep -i arp
> tcpdump: WARNING: eth1: no IPv4 address assigned
> tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
> 11:21:50.462447 fa:16:3e:94:b3:63 > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 10.200.0.50 tell 10.200.0.30, length 28
> 11:21:51.462968 fa:16:3e:94:b3:63 > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 10.200.0.50 tell 10.200.0.30, length 28
> 11:21:52.462330 fa:16:3e:94:b3:63 > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 10.200.0.50 tell 10.200.0.30, length 28
> 11:21:53.462311 fa:16:3e:94:b3:63 > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 10.200.0.50 tell 10.200.0.30, length 28
> 11:21:54.463169 fa:16:3e:94:b3:63 > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 10.200.0.50 tell 10.200.0.30, length 28
> 
> That tcpdump also confirms the ARP packets are not being tagged 200 as they leave the physical interface.
> 
> This worked before when I was testing icehouse RC1, I don't know what changed with Open vSwitch...  Anyone have any ideas?
> 
> Thanks as always for the help!!  This list has been very helpful.
> 
> cheers,
> erich
> 
> 
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