We are experiencing periodic service disruptions and we noticed in the logs that in all occasions, there is the following field values’ combination in the envoy logs:
response_code: 0
response_flags: DC
I see there are several cases where the DC flag may be combined with 5XX error codes, but what could the above combination indicate? Any ideas?
We are facing the same issue ? any solution identified
but what could the above combination indicate?
As DC is DOWNSTREAM_CONNECTION_TERMINATION, I guess the connection was closed before receiving the HTTP Status Code.
As info, in case somebody else asks themselves what DC means.
DOWNSTREAM_CONNECTION_TERMINATION = "DC"
FAILED_LOCAL_HEALTH_CHECK = "LH"
NO_HEALTHY_UPSTREAM = "UH"
UPSTREAM_REQUEST_TIMEOUT = "UT"
LOCAL_RESET = "LR"
UPSTREAM_REMOTE_RESET = "UR"
UPSTREAM_CONNECTION_FAILURE = "UF"
UPSTREAM_CONNECTION_TERMINATION = "UC"
UPSTREAM_OVERFLOW = "UO"
UPSTREAM_RETRY_LIMIT_EXCEEDED = "URX"
NO_ROUTE_FOUND = "NR"
DELAY_INJECTED = "DI"
FAULT_INJECTED = "FI"
RATE_LIMITED = "RL"
UNAUTHORIZED_EXTERNAL_SERVICE = "UAEX"
RATELIMIT_SERVICE_ERROR = "RLSE"
STREAM_IDLE_TIMEOUT = "SI"
INVALID_ENVOY_REQUEST_HEADERS = "IH"
DOWNSTREAM_PROTOCOL_ERROR = "DPE"
UPSTREAM_MAX_STREAM_DURATION_REACHED = "UMSDR"
RESPONSE_FROM_CACHE_FILTER = "RFCF"
NO_FILTER_CONFIG_FOUND = "NFCF"
DURATION_TIMEOUT = "DT"
UPSTREAM_PROTOCOL_ERROR = "UPE"
NO_CLUSTER_FOUND = "NC"
OVERLOAD_MANAGER = "OM"
You can check all response flags here
https://www.envoyproxy.io/docs/envoy/latest/configuration/observability/access_log/usage#config-access-log-format-response-flags