Environmental preparation

Deploy httpbin service ：

kubectl apply -f samples/httpbin/httpbin.yaml

Deploy sleep service ：

kubectl apply -f samples/sleep/sleep.yaml 

httpbin The service is the server that receives the request , sleep The service is the client that sends the request .

Set timeout

stay sleep Service oriented httpbin Service sending request ：

export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- time curl -o /dev/null -sS -w "%{http_code}\n" http://httpbin.org/delay/5

The results are as follows ：

200
real    0m 5.69s
user    0m 0.00s
sys     0m 0.00s

You can see , The request is about 5 Seconds back 200 （OK）.

Create virtual services , visit httpbin The service , The request timeout is set to 3 second ：

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: httpbin
spec:
  hosts:
  - httpbin
  http:
  - route:
    - destination:
        host: httpbin
    timeout: 3s
EOF

Visit again , The results are as follows ：

504
real    0m 3.01s
user    0m 0.00s
sys     0m 0.00s

You can see , stay 3 Seconds later 504 （Gateway Timeout）. Istio stay 3 Seconds later, the response time is 5 Of a second httpbin Service request . Next , Let's take a closer look ,Istio How to cut off the request ？

see Envoy journal

Execute the order , see sleep Service Envoy journal ：

kubectl logs -l app=sleep -c istio-proxy

You can see sleep The service is right httpbin Log of service invocation ：

{
    
     "authority": "httpbin:8000",
     "bytes_received": 0,
     "bytes_sent": 24,
     "connection_termination_details": null,
     "downstream_local_address": "172.24.146.239:8000",
     "downstream_remote_address": "172.24.158.25:40384",
     "duration": 3001,
     "method": "GET",
     "path": "/delay/5",
     "protocol": "HTTP/1.1",
     "request_id": "5ef38816-7f49-48c8-9627-2416e1716293",
     "requested_server_name": null,
     "response_code": 504,
     "response_code_details": "upstream_response_timeout",
     "response_flags": "UT",
     "route_name": null,
     "start_time": "2022-07-01T09:40:13.882Z",
     "upstream_cluster": "outbound|8000||httpbin.onemore.svc.cluster.local",
     "upstream_host": "172.24.158.96:80",
     "upstream_local_address": "172.24.158.25:32846",
     "upstream_service_time": null,
     "upstream_transport_failure_reason": null,
     "user_agent": "curl/7.81.0-DEV",
     "x_forwarded_for": null
}

among ,response_flags by UT, Upstream （upstream） request timeout , That is to say sleep Service detected httpbin The request for the service timed out .

Execute the order , see httpbin Service Envoy journal ：

kubectl logs -l app=httpbin -c istio-proxy

You can see httpbin Service by sleep Called by the service Envoy journal ：

{
    
     "authority": "httpbin:8000",
     "bytes_received": 0,
     "bytes_sent": 0,
     "connection_termination_details": null,
     "downstream_local_address": "172.24.158.96:80",
     "downstream_remote_address": "172.24.158.25:32846",
     "duration": 2997,
     "method": "GET",
     "path": "/delay/5",
     "protocol": "HTTP/1.1",
     "request_id": "5ef38816-7f49-48c8-9627-2416e1716293",
     "requested_server_name": "outbound_.8000_._.httpbin.onemore.svc.cluster.local",
     "response_code": 0,
     "response_code_details": "downstream_remote_disconnect",
     "response_flags": "DC",
     "route_name": "default",
     "start_time": "2022-07-01T09:40:13.885Z",
     "upstream_cluster": "inbound|80||",
     "upstream_host": "172.24.158.96:80",
     "upstream_local_address": "127.0.0.6:35701",
     "upstream_service_time": null,
     "upstream_transport_failure_reason": null,
     "user_agent": "curl/7.81.0-DEV",
     "x_forwarded_for": null
}

among ,response_flags by DC, Means downstream （downstream） The connection is broken , That is to say sleep The call request of the service was interrupted .

In depth analysis

adopt Envoy journal , We can make some analysis and judgment ：

When httpbin Service Request OK When , The calling process is as follows ：

When httpbin Service request timeout When , The calling process is as follows ：

although , We are httpbin The request timeout set on the service , But in fact, it is sleep Service Envoy.

clear

kubectl delete virtualservice httpbin
kubectl delete -f samples/httpbin/httpbin.yaml
kubectl delete -f samples/sleep/sleep.yaml 

Last , Thank you for being so handsome , Give it back to me. give the thumbs-up .