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 related statistics are rooted at server. with following statistics:

Name Type Description
uptime Gauge Current server uptime in seconds
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

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