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Mesh Week: Traffic Management (# 3)

Istio
meshweek
takashi.kanazawatakashi.kanazawa

I tried the mock exam provided by Mesh Week at the following link:

https://docs.google.com/forms/d/e/1FAIpQLSfD4BLLQfdUwnIyiTBSGC_OzmSbiyrIlNp5Am61fTOhRbfiLw/viewform

Question: Traffic Management

Create a VirtualService that injects delays and faults for the “backend” for these cases:

A 5-second delay whenever a request is made to backend.default.svc.cluster.local/delay
An HTTP 403 response whenever a request is made to backend.default.svc.cluster.local/fault

takashi.kanazawatakashi.kanazawa

Answer

Step 1: Install Istio

First, install Istio using the demo profile.

$ istioctl install --set profile=demo
$ kubectl label ns default istio-injection=enabled

Step 2: Create the backend Deployment

Create a deployment named backend using the kennethreitz/httpbin image.

$ kubectl create deployment backend --image=kennethreitz/httpbin

Step 3: Create a Service

Expose the backend deployment using a ClusterIP service.

$ kubectl expose deployment backend --port=80 --type=ClusterIP

Step 4: Create the tester Pod

Create a tester pod using the nginx:alpine image to send requests.

$ kubectl run tester --image=nginx:alpine

Step 5: Verify Resources

Check the status of the created pods and services.

$ kubectl get po,svc -L app

Step 6: Create the VirtualService

Now, create a VirtualService with the following fault injection configurations:

  • Add a 5-second delay for requests to the /delay path.
  • Return a 403 error for requests to the /fault path.
  • Redirect all other requests to /get.

Create a file named backend-vs.yaml with the following content:

apiVersion: networking.istio.io/v1
kind: VirtualService
metadata:
  name: backend
spec:
  hosts:
  - backend
  http:
  - match:
    - uri:
        prefix: "/delay"
    rewrite:
      uri: "/get"
    fault:
      delay:
        percentage:
          value: 100
        fixedDelay: 5s
    route:
    - destination:
        host: backend
  - match:
    - uri:
        prefix: "/fault"
    rewrite:
      uri: "/get"
    fault:
      abort:
        percentage:
          value: 100
        httpStatus: 403
    route:
    - destination:
        host: backend
  - rewrite:
      uri: "/get"
    route:
    - destination:
        host: backend

Apply the VirtualService configuration:

$ kubectl apply -f backend-vs.yaml

Step 7: Test the VirtualService

Send requests from the tester pod to the backend service to verify if the fault injection works as expected.

Normal Request

Run the following command to send a normal request to the backend service.

$ kubectl exec tester -- curl -s -w "time_total:%{time_total}" -o /dev/null -D - http://backend

Response:

HTTP/1.1 200 OK
server: envoy
date: Fri, 06 Sep 2024 05:21:30 GMT
content-type: application/json
content-length: 458
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 1

time_total:0.002987%

Request with Delay

Send a request to the /delay path, which should induce a 5-second delay.

$ kubectl exec tester -- curl -s -w "time_total:%{time_total}" -o /dev/null -D - http://backend/delay

Response:

HTTP/1.1 200 OK
server: envoy
date: Fri, 06 Sep 2024 05:21:40 GMT
content-type: application/json
content-length: 463
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 3

time_total:5.009150%

Request with 403 Error

Send a request to the /fault path, which should return a 403 error.

$ kubectl exec tester -- curl -s -w "time_total:%{time_total}" -o /dev/null -D - http://backend/fault

Response:

HTTP/1.1 403 Forbidden
content-length: 18
content-type: text/plain
date: Fri, 06 Sep 2024 05:21:43 GMT
server: envoy

time_total:0.003623%

Conclusion

I configured a VirtualService in Istio to handle fault injection, including delay and HTTP 403 errors. The test results show that Istio is correctly processing the requests according to the rules defined in the VirtualService.