group PyBal has this configured:
family inet {
unicast {
prefix-limit {
maximum 50;
teardown;
}
}
}
family inet6 {
unicast {
prefix-limit {
maximum 50;
teardown;
}
}
}Which mean if any of the LVS advertise more than 50 prefixes (VIPs), then the router will shutdown the BGP session.
Probably got setup long ago and forgot about it.
This is usually useful for peers we don't trust, so if they screw up their BGP config they don't send us faulty prefixes.
lvs1016 is now at 48 prefixes, codfw top peer at 42.
I see 3 options:
- The easiest is to keep the status quo but bump it to 100 with and add a warning log at 80%.
set protocols bgp group PyBal family inet unicast prefix-limit maximum 100 teardown 80 set protocols bgp group PyBal family inet6 unicast prefix-limit maximum 100 teardown 80
Not sure we will catch it before we have log alerting but it's better than nothing.
- As LVS are trusted peers, we can also remove the teardown, so we start getting logs if we have more than 100 prefixes, but don't take the session down.
But without log alerting we might never know if there is an issue
- Last option is to bump the current value to something very large like 1000 with a teardown 80, so we don't risk forgetting it and hitting the same problem in the future, but we still have some safeguards if pybal starts miss-behaving.
The 3rd option is my preferred one.