Yesterday we had an ELB scale to 26 IP addresses, at which time ALL of the
servers in that backend were suddenly marked down, e.g. :

   Server www26 is going DOWN for maintenance (unspecified DNS error)

Ergo, ALL requests to that backend got 503s ==> complete outage

Mayhap src/dns.c::dns_validate_dns_response() bravely running away when
DNS_RESP_TRUNCATED (skipping parsing of the partial list of servers,
abandoning TTL updates to perfectly good endpoints) is not the best course
of action ?

Of course we'll hope (MTUs allowing) that we'll be able to paper this over
for awhile using an accepted_payload_size >default(512).

But as-is, this looks to be an avoidable pathology?


Yours, endlessly impressed with haproxy,

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