Provide Bidirectional Forwarding and Detection (BFD) protocol based health check for BGP as a Service (BGPaaS) sessions
BFD based health check([6]) feature addresses providing BFD based health check mechanism for any tenant addresses over a particular Virtual Machine Interface (VMI). However, this cannot be directly used for BGPaaS session, as BGPaaS session shares same tenant destination address over a set of VMIs with only one being active at any given time.
In this feature, [6] is complemented with support to run BFD based health checks for BGPaaS sessions as well.
BGPaaS configuration can be enabled on a set of virtual-machine-interfaces, although at any given time, only one of the VMIs will carry the active BGPaaS session packets. As part of configuration of BGPasS object, one can also configure ServiceHealthCheckType property for bgp-as-a-service configuration object.
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diff --git a/src/schema/vnc_cfg.xsd b/src/schema/vnc_cfg.xsd
index 8ea168f..1722673 100644
--- a/src/schema/vnc_cfg.xsd
+++ b/src/schema/vnc_cfg.xsd
@@ -2200,6 +2200,17 @@ targetNamespace="http://www.contrailsystems.com/2012/VNC-CONFIG/0">
Property('bgpaas-suppress-route-advertisement', 'bgp-as-a-service', 'optional', 'CRUD',
'True when server should not advertise any routes to the client i.e. the client has static routes (typically a default) configured.') -->
+<xsd:element name="bgpaas-health-check" type='ServiceHealthCheckType'/>
+ <xsd:annotation>
+ <xsd:documentation>
+ This is used to enable periodic health-check operation over the
+ active BGPaaS vmi.
+ </xsd:documentation>
+ </xsd:annotation>
+<!--#IFMAP-SEMANTICS-IDL
+ Property('bgpaas-health-check', 'bgp-as-a-service', 'optional', 'CRUD',
+ 'Health-Check attributes') -->
+
<xsd:element name="virtual-router" type="ifmap:IdentityType"/>
<xsd:element name="global-system-config-virtual-router"/>
<!--#IFMAP-SEMANTICS-IDL
Users would first configure a service-health-check type object and then associate this object with BGPaaS object as desired.
UI shall provide a way to configure health-check for BGPaaS sessions. Similar to how health checks can be enabled for service interfaces, user should be able to configure BFD based health-check service for BGPaaS sessions. More details on this shall be provided once schema changes are reviewed and approved.
When ever BFD-for-BGP session is marked down by health-checker, appropriate logs and alarms shall be generated. More details on the exact format of this is still TBD.
When ever agent marks BGPaaS as active over a VMI (by enabling the NAT-ed flows towards control-node), if health-check is configured, it shall enable health check as well, over that interface for the BGPaaS session destination address. This includes ping, http or BFD based health checks, as configured. However for BGPaaS, only BFD based health-check is supported.
If health check is enabled for BGPaaS, agent shall configure a new BFD session over the active VMI to the BGPasS destination address. Local address used shall correspond to the local address of the NAT-ed BGP flow (e.g. 192.168.0.1 or 192.168.0.2 as applicable). During switch-over from one interface to another, agent shall also delete the previously configured BFD session.
For BFD based health checks, agent shall use <local-ip, remote-ip, VMI-index> as the BFD session key during configuration. In this case, VMI index is the interface index of the VMI over which BGPaaS is currently active. If BFD packets are received over any other interface, BFD server is expected to drop those packets.
The impact is considered analogous to general health check based services.
Forwarding performance can get affected as CPUs are shared for both ends of the BFD session as well as for all other data traffic forwarding.
HealthCheck infrastructure (including BFD) is treated as integral part of the agent. Hence all aspects of agent upgrade are equally applicable to health check for BGPaaS sessions
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BFD based health check mechanism has goals to add sufficient unit tests. Specific unit tests to cover BGPaaS must also be covered as applicable.