[ovs-discuss] BFD failover not working when gateways are scheduled to compute node chassis

Numan Siddique numans at ovn.org
Wed Apr 22 12:05:54 UTC 2020


On Wed, Apr 22, 2020 at 4:11 PM Brendan Doyle <brendan.doyle at oracle.com> wrote:
>
>
>
> On 22/04/2020 11:15, Numan Siddique wrote:
> > On Wed, Apr 22, 2020 at 3:37 PM Brendan Doyle <brendan.doyle at oracle.com> wrote:
> >> Hi,
> >>
> >> So I have two hypervisors HV1 and HV2
> >>
> >> I have two VMs in the same subnet one on each hypervisor HV1-VM1 and HV2-VM1
> >>
> >> I have a distributed gateway router configured and scheduled to both
> >> hypervisors
> >> Initially scheduled on HV2.
> >>
> >> When I set the network interface on HV2 to down, I expected the gateway
> >> to move
> >> to HV1, but it does not.
> >>
> >> I'm suspecting that it is because HA not supported if the gateway is
> >> scheduled on
> >> compute node hypervisors, as opposed to "controller" hypervisors, is
> >> this true?
> > ovn-controller is not aware if the chassis is a compute or controller
> > hypervisor.
> >
> > The behaviour you're seeing is expected. There is a split brain here since both
> > the hypervisors will think they are masters.
>
> But one has a priority of 20 , the other 15?

In case if you had another chassis HV3 and you boot a VM on this and
the VM's logical switch is connected to the
logical router, then HV1 will become active in your case.

Please see the comment here -
https://github.com/ovn-org/ovn/blob/master/controller/ha-chassis.c#L98.
It has
more details.

Thanks
Numan

>
>
> > You need to have at least 3 gateway
> > chassis configured to the distributed gateway router port.
> >
> > I think we are missing a FAQ document for OVN.
> >
> > Thanks
> > Numan
> >
> >
> >
> >>
> >> details of my config:
> >> ---------------------------
> >> [ca-rain17 ]# ovn-sbctl show
> >> Chassis ca-rain17
> >>       hostname: ca-rain17.us.oracle.com      <--------- OVN "central"
> >>       Encap geneve
> >>           ip: "172.20.1.17"
> >>           options: {csum="true"}
> >> Chassis ca-rain06
> >>       hostname: ca-rain06.us.oracle.com    <---- HV1
> >>       Encap geneve
> >>           ip: "172.20.1.6"
> >>           options: {csum="true"}
> >>       Port_Binding "47433b54-ac10-42f1-ae84-cc6fbb580297"
> >>       Port_Binding "06e85cca-867a-44fc-b2c1-be62f2fb06c0"
> >>       Port_Binding cr-lr_vcn2_igw-ls_external_vcn2
> >> <-- Non HA gateway
> >>       Port_Binding "284195d2-9280-4334-900e-571ecd00327a"
> >> Chassis ca-rain05
> >>       hostname: ca-rain05.us.oracle.com <-- HV2
> >>       Encap geneve
> >>           ip: "172.20.1.5"
> >>           options: {csum="true"}
> >>       Port_Binding cr-lr_vcn1_nat1-ls_external_vcn1 <--- HA gateway
> >>       Port_Binding "ce78fd2b-4c68-428c-baf1-71718e7f3871"
> >>       Port_Binding "269089c4-9464-41ec-9f63-6b3804b34b07"
> >>       Port_Binding "00bff7c0-2e2d-41ba-9485-3b5fa9801365"
> >>       Port_Binding "1cb7d760-90b0-4201-9517-88cb2de31c79"
> >>
> >> [ca-rain17 ]# ovn-nbctl list gateway_chassis
> >> _uuid               : 1b3d74b0-64c1-4715-85fe-e4ec4dfed369
> >> chassis_name        : ca-rain05
> >> external_ids        : {}
> >> name                : lr_vcn1_nat1-ls_external_vcn1-ca-rain05 <-- HA gateway
> >> options             : {}
> >> priority            : 20
> >>
> >> _uuid               : 3ff13911-0010-4afb-b505-653c192da8dc
> >> chassis_name        : ca-rain06
> >> external_ids        : {}
> >> name                : lr_vcn1_nat1-ls_external_vcn1-ca-rain06 <-- HA gateway
> >> options             : {}
> >> priority            : 15
> >>
> >> _uuid               : cb734345-c4b1-4dc9-9cce-3a9ffbab11f7
> >> chassis_name        : ca-rain06
> >> external_ids        : {}
> >> name                : lr_vcn2_igw-ls_external_vcn2-ca-rain06
> >> options             : {}
> >> priority            : 30
> >>
> >> [rca-rain05 ]# ip link set down bond0      <-- set network down on
> >> active gateway hypervisor
> >>
> >>
> >>
> >> [ca-rain17 ]# ovn-sbctl show
> >> Chassis ca-rain17
> >>       hostname: ca-rain17.us.oracle.com
> >>       Encap geneve
> >>           ip: "172.20.1.17"
> >>           options: {csum="true"}
> >> Chassis ca-rain06
> >>       hostname: ca-rain06.us.oracle.com
> >>       Encap geneve
> >>           ip: "172.20.1.6"
> >>           options: {csum="true"}
> >>       Port_Binding "47433b54-ac10-42f1-ae84-cc6fbb580297"
> >>       Port_Binding "06e85cca-867a-44fc-b2c1-be62f2fb06c0"
> >>       Port_Binding cr-lr_vcn2_igw-ls_external_vcn2
> >>       Port_Binding "284195d2-9280-4334-900e-571ecd00327a"
> >> Chassis ca-rain05
> >>       hostname: ca-rain05.us.oracle.com
> >>       Encap geneve
> >>           ip: "172.20.1.5"
> >>           options: {csum="true"}
> >>       Port_Binding cr-lr_vcn1_nat1-ls_external_vcn1 <-- HA gateway did
> >> not move!
> >>       Port_Binding "ce78fd2b-4c68-428c-baf1-71718e7f3871"
> >>       Port_Binding "269089c4-9464-41ec-9f63-6b3804b34b07"
> >>       Port_Binding "00bff7c0-2e2d-41ba-9485-3b5fa9801365"
> >>       Port_Binding "1cb7d760-90b0-4201-9517-88cb2de31c79"
> >>
> >>
> >> Brendan
> >> _______________________________________________
> >> discuss mailing list
> >> discuss at openvswitch.org
> >> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
>
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