Cheatsheet for observability (Metrics, Tracing and Logging) in Istio.




The following figure shows the architecture of Prometheus.

Prometheus architecture

Data model

<metric name>{<label name>=<label value>, ...} value


api_http_requests_total{method="POST", handler="/messages"} 300

Metric types

Types Description Example
Counters A counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase or be reset to zero on restart. Total requests
Gauges A gauge is a metric that represents a single numerical value that can arbitrarily go up and down. Current active requests
Histograms A histogram samples observations (usually things like request durations or response sizes) and counts them in configurable buckets. It also provides a sum of all observed values. Upstream request time


Istio Standard Metrics

Protocol Name Type
HTTP/HTTP2/gRPC istio_requests_total counter
HTTP/HTTP2/gRPC istio_request_duration_milliseconds histogram
HTTP/HTTP2/gRPC istio_request_bytes histogram
HTTP/HTTP2/gRPC istio_response_bytes histogram
HTTP/HTTP2/gRPC istio_request_messages_total counter
HTTP/HTTP2/gRPC istio_response_messages_total counter
TCP istio_tcp_sent_bytes_total counter
TCP istio_tcp_received_bytes_total counter
TCP istio_tcp_connections_opened_total counter
TCP istio_tcp_connections_closed_total counter

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