TCP Traffic Shifting
A common use case is to migrate TCP traffic gradually from one version of a microservice to another. In Istio, you accomplish this goal by configuring a sequence of rules that route a percentage of TCP traffic to one service or another. In this task, you will send 100% of the TCP traffic to . Then, you will route 20% of the TCP traffic to tcp-echo:v2
using Istio’s weighted routing feature.
Setup Istio by following the instructions in the .
Review the Traffic Management concepts doc.
To get started, create a namespace for testing TCP traffic shifting and label it to enable automatic sidecar injection.
Deploy the sample app to use as a test source for sending requests.
$ kubectl apply -f @samples/sleep/sleep.yaml@ -n istio-io-tcp-traffic-shifting
Deploy the
v1
andv2
versions of thetcp-echo
microservice.$ kubectl apply -f @samples/tcp-echo/tcp-echo-services.yaml@ -n istio-io-tcp-traffic-shifting
Follow the instructions in to define the
TCP_INGRESS_PORT
andINGRESS_HOST
environment variables.
Route all TCP traffic to the
v1
version of thetcp-echo
microservice.Confirm that the
tcp-echo
service is up and running by sending some TCP traffic from thesleep
client.$ for i in {1..20}; do \
kubectl exec "$(kubectl get pod -l app=sleep -n istio-io-tcp-traffic-shifting -o jsonpath={.items..metadata.name})" \
done
one Mon Nov 12 23:24:57 UTC 2018
one Mon Nov 12 23:25:00 UTC 2018
one Mon Nov 12 23:25:02 UTC 2018
one Mon Nov 12 23:25:07 UTC 2018
one Mon Nov 12 23:25:10 UTC 2018
one Mon Nov 12 23:25:12 UTC 2018
one Mon Nov 12 23:25:15 UTC 2018
one Mon Nov 12 23:25:17 UTC 2018
one Mon Nov 12 23:25:19 UTC 2018
...
You should notice that all the timestamps have a prefix of one, which means that all traffic was routed to the
v1
version of thetcp-echo
service.Transfer 20% of the traffic from
tcp-echo:v1
totcp-echo:v2
with the following command:$ kubectl apply -f @samples/tcp-echo/tcp-echo-20-v2.yaml@ -n istio-io-tcp-traffic-shifting
Confirm that the rule was replaced:
Send some more TCP traffic to the
tcp-echo
microservice.$ for i in {1..20}; do \
-c sleep -n istio-io-tcp-traffic-shifting -- sh -c "(date; sleep 1) | nc $INGRESS_HOST $TCP_INGRESS_PORT"; \
done
one Mon Nov 12 23:38:45 UTC 2018
two Mon Nov 12 23:38:47 UTC 2018
one Mon Nov 12 23:38:52 UTC 2018
one Mon Nov 12 23:38:55 UTC 2018
two Mon Nov 12 23:38:57 UTC 2018
one Mon Nov 12 23:39:00 UTC 2018
one Mon Nov 12 23:39:02 UTC 2018
one Mon Nov 12 23:39:05 UTC 2018
one Mon Nov 12 23:39:07 UTC 2018
...
You should now notice that about 20% of the timestamps have a prefix of two, which means that 80% of the TCP traffic was routed to the
v1
version of thetcp-echo
service, while 20% was routed tov2
.
In this task you partially migrated TCP traffic from an old to new version of the tcp-echo
service using Istio’s weighted routing feature. Note that this is very different than doing version migration using the deployment features of container orchestration platforms, which use instance scaling to manage the traffic.
With Istio, you can allow the two versions of the tcp-echo
service to scale up and down independently, without affecting the traffic distribution between them.
For more information about version routing with autoscaling, check out the blog article Canary Deployments using Istio.
Remove the
sleep
sample,tcp-echo
application, and routing rules:$ kubectl delete -f @samples/tcp-echo/tcp-echo-all-v1.yaml@ -n istio-io-tcp-traffic-shifting
$ kubectl delete -f @samples/tcp-echo/tcp-echo-services.yaml@ -n istio-io-tcp-traffic-shifting
$ kubectl delete -f @samples/sleep/sleep.yaml@ -n istio-io-tcp-traffic-shifting