LB removes invalid Target neighbor entries #549
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Description
LB applies cluster-wide monitoring of NSM connection Delete events between TAPA and Proxy, to remove invalid Target entries from its Linux neighbor cache preventing connection disturbances.
When TAPA experiences a NSM Heal event for example due to an unexpected connection refresh failure, the NSM connection is first closed and the associated interface is removed. Thus, the MAC address associated with the Target IP(s)
is no longer valid. Even if the same Target IP(s) will get re-assigned when the Heal process concludes, it's unlikely that the same MAC address will be assigned to the new NSM interface.
Feature can be disabled via stateless-lb env variable:
TARGET_DISCONNECT_MONITORING
Also, stateless-lb requires the k8s namespace it's running in to figure out the NSM Network Service name the Conduit (proxy) provides for TAPAs to connect.
Note: Because NSM heal by default (i.e. without datapath monitoring) cleans up the old interface, even with the improvements proposed in this PR some disturbance might be expected (depends both on traffic and on how fast NSM heal could recover the connection).
Issue link
#548
Checklist