Test in production

Test your microservice, in production!

Testing individual microservices

1. Issue an HTTP request from the testing pod to one of your services:

   $ kubectl exec $(kubectl get pod -l app=sleep -o jsonpath='{.items[0].metadata.name}') -- curl -sS http://ratings:9080/ratings/7
   

Chaos testing

Perform some chaos testing⁶ in production and see how your application reacts. After each chaos operation, access the application’s webpage and see if anything changed. Check the pods’ status with kubectl get pods.

1. Terminate the details service in one pod.

   $ kubectl exec $(kubectl get pods -l app=details -o jsonpath='{.items[0].metadata.name}') -- pkill ruby
   

2. Check the pods status:

   $ kubectl get pods
   NAME                            READY   STATUS    RESTARTS   AGE
   details-v1-6d86fd9949-fr59p     1/1     Running   1          47m
   details-v1-6d86fd9949-mksv7     1/1     Running   0          47m
   details-v1-6d86fd9949-q8rrf     1/1     Running   0          48m
   productpage-v1-c9965499-hwhcn   1/1     Running   0          47m
   productpage-v1-c9965499-nccwq   1/1     Running   0          47m
   productpage-v1-c9965499-tjdjx   1/1     Running   0          48m
   ratings-v1-7bf577cb77-cbdsg     1/1     Running   0          47m
   ratings-v1-7bf577cb77-cz6jm     1/1     Running   0          47m
   ratings-v1-7bf577cb77-pq9kg     1/1     Running   0          48m
   reviews-v1-77c65dc5c6-5wt8g     1/1     Running   0          47m
   reviews-v1-77c65dc5c6-kjvxs     1/1     Running   0          48m
   reviews-v1-77c65dc5c6-r55tl     1/1     Running   0          47m
   sleep-88ddbcfdd-l9zq4           1/1     Running   0          47m
   

   Note that the first pod was restarted once.

3. Terminate the details service in all its pods:

   $ for pod in $(kubectl get pods -l app=details -o jsonpath='{.items[*].metadata.name}'); do echo terminating "$pod"; kubectl exec "$pod" -- pkill ruby; done
   

4. Check the webpage of the application:

   

   Note that the details section contains error messages instead of book details.

5. Check the pods status:

   $ kubectl get pods
   NAME                            READY   STATUS    RESTARTS   AGE
   details-v1-6d86fd9949-fr59p     1/1     Running   2          48m
   details-v1-6d86fd9949-mksv7     1/1     Running   1          48m
   details-v1-6d86fd9949-q8rrf     1/1     Running   1          49m
   productpage-v1-c9965499-hwhcn   1/1     Running   0          48m
   productpage-v1-c9965499-nccwq   1/1     Running   0          48m
   productpage-v1-c9965499-tjdjx   1/1     Running   0          48m
   ratings-v1-7bf577cb77-cbdsg     1/1     Running   0          48m
   ratings-v1-7bf577cb77-cz6jm     1/1     Running   0          48m
   ratings-v1-7bf577cb77-pq9kg     1/1     Running   0          49m
   reviews-v1-77c65dc5c6-5wt8g     1/1     Running   0          48m
   reviews-v1-77c65dc5c6-kjvxs     1/1     Running   0          49m
   reviews-v1-77c65dc5c6-r55tl     1/1     Running   0          48m
   sleep-88ddbcfdd-l9zq4           1/1     Running   0          48m
   

   The first pod restarted twice and two other details pods restarted once. You may experience the Error and the CrashLoopBackOff statuses until the pods reach Running status.

6. Use Ctrl-C in the terminal to stop the infinite loop that is running to simulate traffic.

In both cases, the application did not crash. The crash in the details microservice did not cause other microservices to fail. This behavior means you did not have a cascading failure in this situation. Instead, you had gradual service degradation: despite one microservice crashing, the application could still provide useful functionality. It displayed the reviews and the basic information about the book.

You are ready to add a new version of the reviews application⁷.