Statistics

Listener

Every listener has a statistics tree rooted at listener.<address>. (or listener.<stat_prefix>. if stat_prefix is non-empty) with the following statistics:

Name	Type	Description
downstream_cx_total	Counter	Total connections
downstream_cx_destroy	Counter	Total destroyed connections
downstream_cx_active	Gauge	Total active connections
downstream_cx_length_ms	Histogram	Connection length milliseconds
downstream_cx_transport_socket_connect_timeout	Counter	Total connections that timed out during transport socket connection negotiation
downstream_cx_overflow	Counter	Total connections rejected due to enforcement of listener connection limit
downstream_cx_overload_reject	Counter	Total connections rejected due to configured overload actions
downstream_global_cx_overflow	Counter	Total connections rejected due to enforcement of global connection limit
connections_accepted_per_socket_event	Histogram	Number of connections accepted per listener socket event
downstream_pre_cx_timeout	Counter	Sockets that timed out during listener filter processing
downstream_pre_cx_active	Gauge	Sockets currently undergoing listener filter processing
extension_config_missing	Counter	Total connections closed due to missing listener filter extension configuration
global_cx_overflow	Counter	Total connections rejected due to enforcement of the global connection limit
no_filter_chain_match	Counter	Total connections that didn’t match any filter chain
downstream_listener_filter_remote_close	Counter	Total connections closed by remote when peek data for listener filters
downstream_listener_filter_error	Counter	Total numbers of read errors when peeking data for listener filters

TLS statistics

The following TLS statistics are rooted at listener.<address>.ssl.:

Name	Type	Description
connection_error	Counter	Total TLS connection errors not including failed certificate verifications
handshake	Counter	Total successful TLS connection handshakes
session_reused	Counter	Total successful TLS session resumptions
no_certificate	Counter	Total successful TLS connections with no client certificate
fail_verify_no_cert	Counter	Total TLS connections that failed because of missing client certificate
fail_verify_error	Counter	Total TLS connections that failed CA verification
fail_verify_san	Counter	Total TLS connections that failed SAN verification
fail_verify_cert_hash	Counter	Total TLS connections that failed certificate pinning verification
ocsp_staple_failed	Counter	Total TLS connections that failed compliance with the OCSP policy
ocsp_staple_omitted	Counter	Total TLS connections that succeeded without stapling an OCSP response
ocsp_staple_responses	Counter	Total TLS connections where a valid OCSP response was available (irrespective of whether the client requested stapling)
ocsp_staple_requests	Counter	Total TLS connections where the client requested an OCSP staple
ciphers.<cipher>	Counter	Total successful TLS connections that used cipher <cipher>
curves.<curve>	Counter	Total successful TLS connections that used ECDHE curve <curve>
sigalgs.<sigalg>	Counter	Total successful TLS connections that used signature algorithm <sigalg>
versions.<version>	Counter	Total successful TLS connections that used protocol version <version>
was_key_usage_invalid	Counter	Total successful TLS connections that used an invalid keyUsage extension. (This is not avaiable in BoringSSL FIPS yet due to issue #28246)

TCP statistics

The following TCP statistics, which are available when using the TCP stats transport socket, are rooted at listener.<address>.tcp_stats.:

Note

These metrics are provided by the operating system. Due to differences in operating system metrics available and the methodology used to take measurements, the values may not be consistent across different operating systems or versions of the same operating system.

Name	Type	Description
cx_tx_segments	Counter	Total TCP segments transmitted
cx_rx_segments	Counter	Total TCP segments received
cx_tx_data_segments	Counter	Total TCP segments with a non-zero data length transmitted
cx_rx_data_segments	Counter	Total TCP segments with a non-zero data length received
cx_tx_retransmitted_segments	Counter	Total TCP segments retransmitted
cx_rx_bytes_received	Counter	Total payload bytes received for which TCP acknowledgments have been sent.
cx_tx_bytes_sent	Counter	Total payload bytes transmitted (including retransmitted bytes).
cx_tx_unsent_bytes	Gauge	Bytes which Envoy has sent to the operating system which have not yet been sent
cx_tx_unacked_segments	Gauge	Segments which have been transmitted that have not yet been acknowledged
cx_tx_percent_retransmitted_segments	Histogram	Percent of segments on a connection which were retransmistted
cx_rtt_us	Histogram	Smoothed round trip time estimate in microseconds
cx_rtt_variance_us	Histogram	Estimated variance in microseconds of the round trip time. Higher values indicated more variability.

UDP statistics

The following UDP statistics are available for UDP listeners and are rooted at listener.<address>.udp.:

Name	Type	Description
downstream_rx_datagram_dropped	Counter	Number of datagrams dropped due to kernel overflow or truncation

Per-handler Listener Stats

Every listener additionally has a statistics tree rooted at listener.<address>.<handler>. which contains per-handler statistics. As described in the threading model documentation, Envoy has a threading model which includes the main thread as well as a number of worker threads which are controlled by the --concurrency option. Along these lines, <handler> is equal to main_thread, worker_0, worker_1, etc. These statistics can be used to look for per-handler/worker imbalance on either accepted or active connections.

Name	Type	Description
downstream_cx_total	Counter	Total connections on this handler.
downstream_cx_active	Gauge	Total active connections on this handler.

Listener manager

The listener manager has a statistics tree rooted at listener_manager. with the following statistics. Any : character in the stats name is replaced with _.

Name	Type	Description
listener_added	Counter	Total listeners added (either via static config or LDS).
listener_modified	Counter	Total listeners modified (via LDS).
listener_removed	Counter	Total listeners removed (via LDS).
listener_stopped	Counter	Total listeners stopped.
listener_create_success	Counter	Total listener objects successfully added to workers.
listener_create_failure	Counter	Total failed listener object additions to workers.
listener_in_place_updated	Counter	Total listener objects created to execute filter chain update path.
total_filter_chains_draining	Gauge	Number of currently draining filter chains.
total_listeners_warming	Gauge	Number of currently warming listeners.
total_listeners_active	Gauge	Number of currently active listeners.
total_listeners_draining	Gauge	Number of currently draining listeners.
workers_started	Gauge	A boolean (1 if started and 0 otherwise) that indicates whether listeners have been initialized on workers.