This task shows you how to setup request timeouts in Envoy using Istio.
Setup Istio by following the instructions in the Installation guide.
Deploy the BookInfo sample application.
Initialize the application version routing by running the following command:
istioctl create -f samples/bookinfo/kube/route-rule-all-v1.yaml
Note: This task assumes you are deploying the application on Kubernetes. All of the example commands are using the Kubernetes version of the rule yaml files (e.g.,
samples/bookinfo/kube/route-rule-all-v1.yaml
). If you are running this task in a different environment, changekube
to the directory that corresponds to your runtime (e.g.,samples/bookinfo/consul/route-rule-all-v1.yaml
for the Consul-based runtime).
A timeout for http requests can be specified using the httpReqTimeout field of a routing rule. By default, the timeout is 15 seconds, but in this task we’ll override the reviews
service timeout to 1 second. To see its effect, however, we’ll also introduce an artificial 2 second delay in calls to the ratings
service.
Route requests to v2 of the reviews
service, i.e., a version that calls the ratings
service
cat <<EOF | istioctl replace -f -
apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
name: reviews-default
spec:
destination:
name: reviews
route:
- labels:
version: v2
EOF
Add a 2 second delay to calls to the ratings
service:
cat <<EOF | istioctl replace -f -
apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
name: ratings-default
spec:
destination:
name: ratings
route:
- labels:
version: v1
httpFault:
delay:
percent: 100
fixedDelay: 2s
EOF
Open the BookInfo URL (http://$GATEWAY_URL/productpage) in your browser
You should see the BookInfo application working normally (with ratings stars displayed), but there is a 2 second delay whenever you refresh the page.
Now add a 1 second request timeout for calls to the reviews
service
cat <<EOF | istioctl replace -f -
apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
name: reviews-default
spec:
destination:
name: reviews
route:
- labels:
version: v2
httpReqTimeout:
simpleTimeout:
timeout: 1s
EOF
Refresh the BookInfo web page
You should now see that it returns in 1 second (instead of 2), but the reviews are unavailable.
In this task, you used Istio to set the request timeout for calls to the reviews
microservice to 1 second (instead of the default 15 seconds). Since the reviews
service subsequently calls the ratings
service when handling requests, you used Istio to inject a 2 second delay in calls to ratings
, so that you would cause the reviews
service to take longer than 1 second to complete and consequently you could see the timeout in action.
You observed that the BookInfo productpage (which calls the reviews
service to populate the page), instead of displaying reviews, displayed the message: Sorry, product reviews are currently unavailable for this book. This was the result of it receiving the timeout error from the reviews
service.
If you check out the fault injection task, you’ll find out that the productpage
microservice also has its own application-level timeout (3 seconds) for calls to the reviews
microservice. Notice that in this task we used an Istio route rule to set the timeout to 1 second. Had you instead set the timeout to something greater than 3 seconds (e.g., 4 seconds) the timeout would have had no effect since the more restrictive of the two will take precedence. More details can be found here.
One more thing to note about timeouts in Istio is that in addition to overriding them in route rules, as you did in this task, they can also be overridden on a per-request basis if the application adds an “x-envoy-upstream-rq-timeout-ms” header on outbound requests. In the header the timeout is specified in millisecond (instead of second) units.
Remove the application routing rules.
istioctl delete -f samples/bookinfo/kube/route-rule-all-v1.yaml
If you are not planning to explore any follow-on tasks, refer to the BookInfo cleanup instructions to shutdown the application.
Learn more about failure handling.
Learn more about routing rules.