Hi Ammad,


On Tue, Mar 16, 2021 at 9:15 AM Ammad Syed <syedammad83@gmail.com> wrote:
>
> Hi,
>
> I have four compute nodes in my lab setup. Initially all the four compute nodes were acting as gateway chassis with priority 1, 2, 3 and 4.
>
> Then I have specifically marked two node as a gateway chassis with below command on compute nodes.
>
> ovs-vsctl set open . external-ids:ovn-cms-options="enable-chassis-as-gw"
>
> The command ovn-nbctl list gateway_chassis start showing two chassis. I have checked via tcpdump, the public traffic started flowing from both nodes. Look like its doing round robin to send packets.
>
> Then I tried to remove one chassis from gateway and used below command.
>
> ovs-vsctl remove open . external-ids ovn-cms-options=enable-chassis-as-gw
>
> The  ovn-nbctl list gateway_chassis started showing one gateway chassis but I can see from tcpdump that public traffic still flows from both gateway chassis.
>
> Below is the current status of chassis.
>
> root@network:/etc/neutron# ovn-sbctl list chassis
> _uuid               : 532bb9d0-6667-462c-9631-0cb5360bd4dc
> encaps              : [358c4a59-0bca-459c-958c-524eb8c385ce]
> external_ids        : {datapath-type=system, iface-types="erspan,geneve,gre,internal,ip6erspan,ip6gre,lisp,patch,stt,system,tap,vxlan", is-interconn="false", "neutron:liveness_check_at"="2021-03-16T08:52:41.361302+00:00", "neutron:metadata_liveness_check_at"="2021-03-16T08:52:41.364928+00:00", "neutron:ovn-metadata-id"="2ac66785-d0c7-43ee-8c78-5fd6ed6ccc73", "neutron:ovn-metadata-sb-cfg"="6157", ovn-bridge-mappings="ext-net1:br-ext", ovn-chassis-mac-mappings="", ovn-cms-options=""}
> hostname            : virtual-hv2
> name                : "fdfae005-7473-486a-b331-8a54c53c1279"
> nb_cfg              : 6157
> transport_zones     : []
> vtep_logical_switches: []
>
> _uuid               : a99ab389-96a5-4a58-a301-34618868450a
> encaps              : [6e7490ce-3c58-4a1c-999d-ff1638c66feb]
> external_ids        : {datapath-type=system, iface-types="erspan,geneve,gre,internal,ip6erspan,ip6gre,lisp,patch,stt,system,tap,vxlan", is-interconn="false", neutron-metadata-proxy-networks="dc917847-f70f-4de0-9865-3e9594c65ef1", "neutron:liveness_check_at"="2021-03-16T08:52:41.368768+00:00", "neutron:metadata_liveness_check_at"="2021-03-16T08:52:41.372045+00:00", "neutron:ovn-metadata-id"="3441fc3c-ca43-4360-8210-8c9ebe4fc13d", "neutron:ovn-metadata-sb-cfg"="6157", ovn-bridge-mappings="ext-net1:br-ext", ovn-chassis-mac-mappings="", ovn-cms-options=""}
> hostname            : kvm10-a1-khi01
> name                : "87504098-4474-40fc-9576-ac449c1c4448"
> nb_cfg              : 6157
> transport_zones     : []
> vtep_logical_switches: []
>
> _uuid               : b9bdfe12-fe27-4580-baee-159f871c442b
> encaps              : [52a8f523-9740-4333-a4a4-69bf5e27117c]
> external_ids        : {datapath-type=system, iface-types="erspan,geneve,gre,internal,ip6erspan,ip6gre,lisp,patch,stt,system,tap,vxlan", is-interconn="false", neutron-metadata-proxy-networks="dc917847-f70f-4de0-9865-3e9594c65ef1", "neutron:liveness_check_at"="2021-03-16T08:52:41.326719+00:00", "neutron:metadata_liveness_check_at"="2021-03-16T08:52:41.342214+00:00", "neutron:ovn-metadata-id"="2a751610-97a8-4688-a719-df3616f4f770", "neutron:ovn-metadata-sb-cfg"="6157", ovn-bridge-mappings="ext-net1:br-ext", ovn-chassis-mac-mappings="", ovn-cms-options=""}
> hostname            : kvm12-a1-khi01
> name                : "82630e57-668e-4f67-a3fb-a173f4da432a"
> nb_cfg              : 6157
> transport_zones     : []
> vtep_logical_switches: []
>
> _uuid               : 669d1ae3-7a5d-4ec3-869d-ca6240f9ae2c
> encaps              : [ac8022b3-1ea5-45c7-a7e8-74db7b627df4]
> external_ids        : {datapath-type=system, iface-types="erspan,geneve,gre,internal,ip6erspan,ip6gre,lisp,patch,stt,system,tap,vxlan", is-interconn="false", "neutron:liveness_check_at"="2021-03-16T08:52:41.347144+00:00", "neutron:metadata_liveness_check_at"="2021-03-16T08:52:41.352021+00:00", "neutron:ovn-metadata-id"="2d5ce6fd-6a9f-4356-9406-6ca91601af43", "neutron:ovn-metadata-sb-cfg"="6157", ovn-bridge-mappings="ext-net1:br-ext", ovn-chassis-mac-mappings="", ovn-cms-options=enable-chassis-as-gw}
> hostname            : virtual-hv1
> name                : "731e842a-3a69-4044-87e9-32b7517d4f07"
> nb_cfg              : 6157
> transport_zones     : []
> vtep_logical_switches: []
>
> Need help how can I permanently remove a gateway chassis that it should stop serving public traffic ? also is it something to do with priority ?
>

Is it possible that we still have router ports scheduled onto that chassis ?

You list your routers, router_ports and which gateway chassis the port
is scheduled on with the following commands:

# List your routers
$ ovn-nbctl lr-list

# List the router ports in that router
$ ovn-nbctl lrp-list <router id>

# List which gateway chassis (if any) that router port is scheduled
on. Here you will see the priority, the highest is where the port
should be located
$ ovn-nbctl lrp-get-gateway-chassis <router port id>

If that's the case, I think the OVN driver is not automatically
accounting for rescheduling these ports when a gateway chassis is
removed/added. We need to discuss whether this is something we want to
have automatically like this or not because it can cause data
disruption.

Alternatively we could have a "rescheduling" script that could be run
by operators when they want to add/remove a gateway chassis so they
can plan before moving the ports from one chassis to another (again
potentially causing disruptions).

Hope that helps,
Lucas

> - Ammad