基本術語
- Downstream（下游）：下游主機連接到 Envoy，發送請求並接收響應，即發送請求的主機。
- Upstream（上游）：上游主機接收來自 Envoy 的連接和請求，並返回響應，即接受請求的主機。
- Listener（監聽器）：監聽器是命名網地址（例如，端口、unix domain socket 等)，下游客戶端可以連接這些監聽器。Envoy 暴露一個或者多個監聽器給下游主機連接。
- Cluster（集群）：集群是指 Envoy 連接的一組邏輯相同的上游主機。Envoy 通過服務發現來發現集群的成員。可以選擇通過主動健康檢查來確定集群成員的健康狀態。Envoy 通過負載均衡策略決定將請求路由到集群的哪個成員。
client ---> nginx(upstream)--->后端服務
對應envoy:
downstream(下游) ---> envoy ----->upstream(上游)
istio訪問日志常見標識碼
HTTP and TCP
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UH: No healthy upstream hosts in upstream cluster in addition to 503 response code.
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UF: Upstream connection failure in addition to 503 response code.
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UO: Upstream overflow (circuit breaking) in addition to 503 response code.
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NR: No route configured for a given request in addition to 404 response code.
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URX: The request was rejected because the upstream retry limit (HTTP) or maximum connect attempts (TCP) was reached.
HTTP only
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DC: Downstream connection termination.
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LH: Local service failed health check request in addition to 503 response code.
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UT: Upstream request timeout in addition to 504 response code.
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LR: Connection local reset in addition to 503 response code.
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UR: Upstream remote reset in addition to 503 response code.
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UC: Upstream connection termination in addition to 503 response code.
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DI: The request processing was delayed for a period specified via fault injection.
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FI: The request was aborted with a response code specified via fault injection.
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RL: The request was ratelimited locally by the HTTP rate limit filter in addition to 429 response code.
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UAEX: The request was denied by the external authorization service.
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RLSE: The request was rejected because there was an error in rate limit service.
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IH: The request was rejected because it set an invalid value for a strictly-checked header in addition to 400 response code.
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SI: Stream idle timeout in addition to 408 response code.
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DPE: The downstream request had an HTTP protocol error.