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What are the golden signals Istio exposes (latency, traffic, errors, saturation)?
Istio & Service Mesh · Intermediate level
Answer
Istio exposes the golden signals as traffic, errors, latency, and saturation-related proxy metrics. For SRE work, I alert on error-rate burn, p95/p99 latency, request volume changes, and gateway or proxy saturation rather than just pod health.
Technical explanation
Traffic is represented by request rate and byte counters.
Errors are response codes, gRPC status, reset reasons, and policy denials.
Latency is captured in histograms; saturation is inferred from proxy CPU/memory, connection counts, pending requests, and gateway load.
Hands-on example
Dashboard panels:
1. RPS by source and destination.
2. 5xx percentage by destination workload.
3. p95 and p99 latency by route.
4. Envoy CPU/memory for gateways and high-volume sidecars.
5. mTLS or authorization denials after policy changes.
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