Statistics

A few statistics are emitted to report statistics system behavior:

Name	Type	Description
stats.overflow	Counter	Total number of times Envoy cannot allocate a statistic due to a shortage of shared memory

Server

Server related statistics are rooted at server. with following statistics:

Name	Type	Description
uptime	Gauge	Current server uptime in seconds
concurrency	Gauge	Number of worker threads
memory_allocated	Gauge	Current amount of allocated memory in bytes. Total of both new and old Envoy processes on hot restart.
memory_heap_size	Gauge	Current reserved heap size in bytes. New Envoy process heap size on hot restart.
live	Gauge	1 if the server is not currently draining, 0 otherwise
parent_connections	Gauge	Total connections of the old Envoy process on hot restart
total_connections	Gauge	Total connections of both new and old Envoy processes
version	Gauge	Integer represented version number based on SCM revision
days_until_first_cert_expiring	Gauge	Number of days until the next certificate being managed will expire
hot_restart_epoch	Gauge	Current hot restart epoch
debug_assertion_failures	Counter	Number of debug assertion failures detected in a release build if compiled with –define log_debug_assert_in_release=enabled or zero otherwise

File system

Statistics related to file system are emitted in the filesystem. namespace.

Name	Type	Description
write_buffered	Counter	Total number of times file data is moved to Envoy’s internal flush buffer
write_completed	Counter	Total number of times a file was written
flushed_by_timer	Counter	Total number of times internal flush buffers are written to a file due to flush timeout
reopen_failed	Counter	Total number of times a file was failed to be opened
write_total_buffered	Gauge	Current total size of internal flush buffer in bytes