Statistics

Every connection manager has a statistics tree rooted at http.<stat_prefix>. with the following statistics:

Name Type Description
downstream_cx_total Counter Total connections
downstream_cx_ssl_total Counter Total TLS connections
downstream_cx_http1_total Counter Total HTTP/1.1 connections
downstream_cx_upgrades_total Counter Total successfully upgraded connections. These are also counted as total http1/http2 connections.
downstream_cx_http2_total Counter Total HTTP/2 connections
downstream_cx_destroy Counter Total connections destroyed
downstream_cx_destroy_remote Counter Total connections destroyed due to remote close
downstream_cx_destroy_local Counter Total connections destroyed due to local close
downstream_cx_destroy_active_rq Counter Total connections destroyed with 1+ active request
downstream_cx_destroy_local_active_rq Counter Total connections destroyed locally with 1+ active request
downstream_cx_destroy_remote_active_rq Counter Total connections destroyed remotely with 1+ active request
downstream_cx_active Gauge Total active connections
downstream_cx_ssl_active Gauge Total active TLS connections
downstream_cx_http1_active Gauge Total active HTTP/1.1 connections
downstream_cx_upgrades_active Gauge Total active upgraded connections. These are also counted as active http1/http2 connections.
downstream_cx_http2_active Gauge Total active HTTP/2 connections
downstream_cx_protocol_error Counter Total protocol errors
downstream_cx_length_ms Histogram Connection length milliseconds
downstream_cx_rx_bytes_total Counter Total bytes received
downstream_cx_rx_bytes_buffered Gauge Total received bytes currently buffered
downstream_cx_tx_bytes_total Counter Total bytes sent
downstream_cx_tx_bytes_buffered Gauge Total sent bytes currently buffered
downstream_cx_drain_close Counter Total connections closed due to draining
downstream_cx_idle_timeout Counter Total connections closed due to idle timeout
downstream_cx_overload_disable_keepalive Counter Total connections for which HTTP 1.x keepalive has been disabled due to Envoy overload
downstream_flow_control_paused_reading_total Counter Total number of times reads were disabled due to flow control
downstream_flow_control_resumed_reading_total Counter Total number of times reads were enabled on the connection due to flow control
downstream_rq_total Counter Total requests
downstream_rq_http1_total Counter Total HTTP/1.1 requests
downstream_rq_http2_total Counter Total HTTP/2 requests
downstream_rq_active Gauge Total active requests
downstream_rq_response_before_rq_complete Counter Total responses sent before the request was complete
downstream_rq_rx_reset Counter Total request resets received
downstream_rq_tx_reset Counter Total request resets sent
downstream_rq_non_relative_path Counter Total requests with a non-relative HTTP path
downstream_rq_too_large Counter Total requests resulting in a 413 due to buffering an overly large body
downstream_rq_completed Counter Total requests that resulted in a response (e.g. does not include aborted requests)
downstream_rq_1xx Counter Total 1xx responses
downstream_rq_2xx Counter Total 2xx responses
downstream_rq_3xx Counter Total 3xx responses
downstream_rq_4xx Counter Total 4xx responses
downstream_rq_5xx Counter Total 5xx responses
downstream_rq_ws_on_non_ws_route Counter Total WebSocket upgrade requests rejected by non WebSocket routes
downstream_rq_time Histogram Total time for request and response (milliseconds)
downstream_rq_idle_timeout Counter Total requests closed due to idle timeout
downstream_rq_timeout Counter Total requests closed due to a timeout on the request path
downstream_rq_overload_close Counter Total requests closed due to Envoy overload
rs_too_large Counter Total response errors due to buffering an overly large body

Per user agent statistics

Additional per user agent statistics are rooted at http.<stat_prefix>.user_agent.<user_agent>. Currently Envoy matches user agent for both iOS (ios) and Android (android) and produces the following statistics:

Name Type Description
downstream_cx_total Counter Total connections
downstream_cx_destroy_remote_active_rq Counter Total connections destroyed remotely with 1+ active requests
downstream_rq_total Counter Total requests

Per listener statistics

Additional per listener statistics are rooted at listener.<address>.http.<stat_prefix>. with the following statistics:

Name Type Description
downstream_rq_completed Counter Total responses
downstream_rq_1xx Counter Total 1xx responses
downstream_rq_2xx Counter Total 2xx responses
downstream_rq_3xx Counter Total 3xx responses
downstream_rq_4xx Counter Total 4xx responses
downstream_rq_5xx Counter Total 5xx responses

Per codec statistics

Each codec has the option of adding per-codec statistics. Currently only http2 has codec stats.

Http2 codec statistics

All http2 statistics are rooted at http2.

Name Type Description
header_overflow Counter Total number of connections reset due to the headers being larger than the configured value.
headers_cb_no_stream Counter Total number of errors where a header callback is called without an associated stream. This tracks an unexpected occurrence due to an as yet undiagnosed bug
inbound_empty_frames_flood Counter Total number of connections terminated for exceeding the limit on consecutive inbound frames with an empty payload and no end stream flag. The limit is configured by setting the max_consecutive_inbound_frames_with_empty_payload config setting.
inbound_priority_frames_flood Counter Total number of connections terminated for exceeding the limit on inbound frames of type PRIORITY. The limit is configured by setting the max_inbound_priority_frames_per_stream config setting.
inbound_window_update_frames_flood Counter Total number of connections terminated for exceeding the limit on inbound frames of type WINDOW_UPDATE. The limit is configured by setting the max_inbound_window_updateframes_per_data_frame_sent config setting.
outbound_flood Counter Total number of connections terminated for exceeding the limit on outbound frames of all types. The limit is configured by setting the max_outbound_frames config setting.
outbound_control_flood Counter Total number of connections terminated for exceeding the limit on outbound frames of types PING, SETTINGS and RST_STREAM. The limit is configured by setting the max_outbound_control_frames config setting.
rx_messaging_error Counter Total number of invalid received frames that violated section 8 of the HTTP/2 spec. This will result in a tx_reset
rx_reset Counter Total number of reset stream frames received by Envoy
too_many_header_frames Counter Total number of times an HTTP2 connection is reset due to receiving too many headers frames. Envoy currently supports proxying at most one header frame for 100-Continue one non-100 response code header frame and one frame with trailers
trailers Counter Total number of trailers seen on requests coming from downstream
tx_reset Counter Total number of reset stream frames transmitted by Envoy

Tracing statistics

Tracing statistics are emitted when tracing decisions are made. All tracing statistics are rooted at http.<stat_prefix>.tracing. with the following statistics:

Name Type Description
random_sampling Counter Total number of traceable decisions by random sampling
service_forced Counter Total number of traceable decisions by server runtime flag tracing.global_enabled
client_enabled Counter Total number of traceable decisions by request header x-envoy-force-trace
not_traceable Counter Total number of non-traceable decisions by request id
health_check Counter Total number of non-traceable decisions by health check