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_http3_total	Counter	Total HTTP/3 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_http1_soft_drain	Gauge	Total active HTTP/1.x connections waiting for another downstream request to safely close the connection.
downstream_cx_http2_active	Gauge	Total active HTTP/2 connections
downstream_cx_http3_active	Gauge	Total active HTTP/3 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_max_duration_reached	Counter	Total connections closed due to max connection duration
downstream_cx_max_requests_reached	Counter	Total connections closed due to max requests per connection
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_http3_total	Counter	Total HTTP/3 requests
downstream_rq_active	Gauge	Total active requests
downstream_rq_rejected_via_ip_detection	Counter	Total requests rejected because the original IP detection failed
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_failed_path_normalization	Counter	Total requests redirected due to different original and normalized URL paths or when path normalization failed. This action is configured by setting the path_with_escaped_slashes_action config option.
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 upgrade requests rejected by non upgrade routes. This now applies both to WebSocket and non-WebSocket upgrades
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_max_duration_reached	Counter	Total requests closed due to max duration reached
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
downstream_rq_redirected_with_normalized_path	Counter	Total requests redirected due to different original and normalized URL paths. This action is configured by setting the path_with_escaped_slashes_action config option.
downstream_rq_too_many_premature_resets	Counter	Total number of connections closed due to too many premature request resets on the connection.
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

Per listener statistics are rooted at listener.<address>..

HTTP per listener statistics

Additional HTTP statistics are of the form 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

HTTP/3 per listener statistics

HTTP/3 statistics with the form of http3.downstream.<stat_prefix>.:

Name	Type	Description
<tx/rx>.quic_connection_close_error_code_<error_code>	Counter	A collection of counters that are lazily initialized to record each quic connection close error code that’s present.
<tx/rx>.quic_reset_stream_error_code_<error_code>	Counter	A collection of counters that that lazily initialized to record quic stream reset error codes.

Per codec statistics

Each codec has the option of adding per-codec statistics. http1, http2, and http3 all have codec stats.

HTTP/1 codec statistics

On the downstream side all http1 statistics are rooted at http1.

On the upstream side all http1 statistics are rooted at cluster.<name>.http1.

Name	Type	Description
dropped_headers_with_underscores	Counter	Total number of dropped headers with names containing underscores. This action is configured by setting the headers_with_underscores_action config setting.
metadata_not_supported_error	Counter	Total number of metadata dropped during HTTP/1 encoding
response_flood	Counter	Total number of connections closed due to response flooding
requests_rejected_with_underscores_in_headers	Counter	Total numbers of rejected requests due to header names containing underscores. This action is configured by setting the headers_with_underscores_action config setting.

HTTP/2 codec statistics

On the downstream side all http2 statistics are rooted at http2.

On the upstream side all http2 statistics are rooted at cluster.<name>.http2.

Name	Type	Description
dropped_headers_with_underscores	Counter	Total number of dropped headers with names containing underscores. This action is configured by setting the headers_with_underscores_action config setting.
goaway_sent	Counter	Total number GOAWAY frames that have been submitted to the codec to send.
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.
keepalive_timeout	Counter	Total number of connections closed due to keepalive timeout
metadata_empty_frames	Counter	Total number of metadata frames that were received and contained empty maps.
outbound_control_frames_active	Gauge	Total outbound control frames that are active.
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.
outbound_frames_active	Gauge	Total outbound frames that are active.
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.
requests_rejected_with_underscores_in_headers	Counter	Total numbers of rejected requests due to header names containing underscores. This action is configured by setting the headers_with_underscores_action 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
stream_refused_errors	Counter	Total number of invalid frames received by Envoy with a REFUSED_STREAM error code
trailers	Counter	Total number of trailers seen on requests coming from downstream
tx_flush_timeout	Counter	Total number of stream idle timeouts waiting for open stream window to flush the remainder of a stream
tx_reset	Counter	Total number of reset stream frames transmitted by Envoy
streams_active	Gauge	Active streams as observed by the codec
pending_send_bytes	Gauge	Currently buffered body data in bytes waiting to be written when stream/connection window is opened.
deferred_stream_close	Gauge	Number of HTTP/2 streams where the stream has been closed but processing of the stream close has been deferred due to network backup. This is expected to be incremented when a downstream stream is backed up and the corresponding upstream stream has received end stream but we defer processing of the upstream stream close due to downstream backup. This is decremented as we finally delete the stream when either the deferred close stream has its buffered data drained or receives a reset.

Attention

The HTTP/2 streams_active gauge may be greater than the HTTP connection manager downstream_rq_active gauge due to differences in stream accounting between the codec and the HTTP connection manager.

HTTP/3 codec statistics

On the downstream side all http3 statistics are rooted at http3.

On the upstream side all http3 statistics are rooted at cluster.<name>.http3.

Name	Type	Description
dropped_headers_with_underscores	Counter	Total number of dropped headers with names containing underscores. This action is configured by setting the headers_with_underscores_action config setting.
requests_rejected_with_underscores_in_headers	Counter	Total numbers of rejected requests due to header names containing underscores. This action is configured by setting the headers_with_underscores_action config setting.
rx_reset	Counter	Total number of reset stream frames received by Envoy
tx_reset	Counter	Total number of reset stream frames transmitted by Envoy
metadata_not_supported_error	Counter	Total number of metadata dropped during HTTP/3 encoding
quic_version_h3_29	Counter	Total number of quic connections that use transport version h3-29. QUIC h3-29 is unsupported by default and this counter will be removed when h3-29 support is completely removed.
quic_version_rfc_v1	Counter	Total number of quic connections that use transport version rfc-v1.

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