1.istio-pilot日誌級別
編輯istio-system.deployment.istio-pilot，修改args中--log_output_level=default:指定日誌級別
2.istio-policy日誌級別設置同istio-pilot
3.istio-proxy（envoy）日誌級別設置
進入istio-proxy容器中，通過如下命令進行設置：
curl -X POST localhost:15000/logging?level=trace
4.istio-proxy access日誌設置
官方參考：https://istio.io/docs/tasks/telemetry/logs/access-log/
修改istio-system.configMap.istio中的accessLogFile: "/dev/stdout"
修改後即可在istio-proxy看到如下accessLog（業務app pod容器無需重啓）：
默認accessLogFormat：
通過如下命令查看accessLogFormat配置：
istioctl proxy-config listeners <your pod> -n <your namespace> -o json
[%START_TIME%] \"%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%\" %RESPONSE_CODE% %RESPONSE_FLAGS% \"%DYNAMIC_METADATA(istio.mixer:status)%\" %BYTES_RECEIVED% %BYTES_SENT% %DURATION% %RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)% \"%REQ(X-FORWARDED-FOR)%\" \"%REQ(USER-AGENT)%\" \"%REQ(X-REQUEST-ID)%\" \"%REQ(:AUTHORITY)%\" \"%UPSTREAM_HOST%\" %UPSTREAM_CLUSTER% %UPSTREAM_LOCAL_ADDRESS% %DOWNSTREAM_LOCAL_ADDRESS% %DOWNSTREAM_REMOTE_ADDRESS% %REQUESTED_SERVER_NAME%\n
實際日誌與默認格式對比：
[2019-09-24T05:57:56.836Z]
"POST /256/vendorRetire/list HTTP/1.1"
200 - "-"
113 6029 110 110
"-" "Apache-HttpClient/4.5.7 (Java/1.8.0_192)" "d17359bf-7b4c-4c44-8dab-003c59fa810b" "s267.tsp"
"127.0.0.1:8080" inbound|80|http|s267.tsp.svc.cluster.local -
172.25.193.104:8080 172.25.123.74:33340 -====================================================================================
[%START_TIME%]
\"%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%\"
%RESPONSE_CODE% %RESPONSE_FLAGS% \"%DYNAMIC_METADATA(istio.mixer:status)%\"
%BYTES_RECEIVED% %BYTES_SENT% %DURATION% %RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%
\"%REQ(X-FORWARDED-FOR)%\" \"%REQ(USER-AGENT)%\" \"%REQ(X-REQUEST-ID)%\" \"%REQ(:AUTHORITY)%\"
\"%UPSTREAM_HOST%\" %UPSTREAM_CLUSTER% %UPSTREAM_LOCAL_ADDRESS%
%DOWNSTREAM_LOCAL_ADDRESS% %DOWNSTREAM_REMOTE_ADDRESS% %REQUESTED_SERVER_NAME%\n
其中RESPONSE_FLAGS定義如下：
envoy log參考：
Envoy官方參考 - access_log#config-access-log-default-format
stackoverflow - what-is-istio-proxy-access-log-mean
5.Springboot Tomcat訪問日誌
開啓如下配置：
server.tomcat.accesslog.enabled = true
server.tomcat.accesslog.directory = /data/logs/tomcat
即可在應用容器中/data/logs/tomcat看到如下訪問日誌：
查看最近的access_log即可看到tomcat的訪問日誌：
