What is your user-agent?

https://www.whoishostingthis.com/tools/user-agent/

Note: the "user-agent" header is added to OpenTracing baggage in the Customer service. From there it is automatically propagated to all downstream services. To enable automatic baggage propagation all intermediate services have to be instrumented with OpenTracing. The baggage header for user-agent has the following form baggage-user-agent: <value>.

Let's create a rule that points all request to v1 using the files /istiofiles/destination-rule-recommendation-v1-v2.yml and /istiofiles/virtual-service-recommendation-v1.yml.

istioctl create -f ~/projects/istio-tutorial/istiofiles/destination-rule-recommendation-v1-v2.yml -n tutorial; \ istioctl create -f ~/projects/istio-tutorial/istiofiles/virtual-service-recommendation-v1.yml -n tutorial

Check this behavior trying the microservice several times by typing while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .1; done

Hit CTRL+C when you are satisfied.

Now check the file /istiofiles/virtual-service-safari-recommendation-v2.yml.

Note that this VirtualService will only route request to recommendations, subset: version-v2 that contains the label version=v2 http contains a baggage header baggage-user-agent where the value matches the regex expression to ".*Safari.*".

Let's replace the virtualservice: istioctl replace -f ~/projects/istio-tutorial/istiofiles/virtual-service-safari-recommendation-v2.yml -n tutorial

Now test the URL http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com with a Safari (or even Chrome on Mac since it includes Safari in the string). Safari only sees v2 responses from recommendations

and test with a Firefox browser, it should only see v1 responses from recommendations.

Try this rule using curl

If you don't have these browsers you can customiza the curl command user-agent using -A.

For example. Try curl -A Safari http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com

Alternatively you can try a Firefox user-agent with curl -A Firefox http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com

You can describe the routerule to see its configuration: istioctl get virtualservice recommendation -o yaml -n tutorial

Remove 'Safari' rule.

To remove the User-Agent behavior, simply delete this virtualservice by executing istioctl delete virtualservice recommendation -n tutorial

To check if you have all requests using v1, try the microservice several times by typing curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com

You still have the requests going to v1 because you didn't remove the RouteRule recommendation-default.

Clean up

Don't forget to remove the virtualservice and destinationrule executing ~/projects/istio-tutorial/scripts/clean.sh

You should have 2 pods for recommendation based on the command bellow:

oc get pods -l app=recommendation -n tutorial

Check the files istiofiles/destination-rule-recommendation-v1-v2.yml and istiofiles/virtual-service-recommendation-v1-mirror-v2.yml.

Note that the virtualservice routes the requests to recommendation, subset: version-v1. However, it also mirror these requests to recommendation, subset: version-v2.

Let's apply these files: istioctl create -f ~/projects/istio-tutorial/istiofiles/destination-rule-recommendation-v1-v2.yml -n tutorial; \ istioctl create -f ~/projects/istio-tutorial/istiofiles/virtual-service-recommendation-v1-mirror-v2.yml -n tutorial

Now, send several requests to the microservices on Terminal 2 to see their responses while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .5; done

Note that it only replies from v1.

Check the logs of recommendation:v2 to make sure that it received the request although we saw only v1 response.

oc logs -f $(oc get pods|grep recommendation-v2|awk '{ print $1 }') -c recommendation

Hit CTRL+C when you are satisfied.

Clean up

Don't forget to remove the virtualservice and destinationrule executing ~/projects/istio-tutorial/scripts/clean.sh

By default, you will see "round-robin" style load-balancing, but you can change it up, with the RANDOM option being fairly visible to the naked eye.

Add another v2 pod to the mix oc scale deployment recommendation-v2 --replicas=2 -n tutorial

Watch the creation of the pods executing oc get pods -w

Once that the recommendation pods READY column are 2/2, you can hit CTRL+C.

Now, send several requests to the microservices on Terminal 2 to see their responses while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .5; done

Add a 3rd v2 pod to the mix oc scale deployment recommendation-v2 --replicas=3 -n tutorial

Watch the creation of the pods executing oc get pods -w

Once that the recommendation pods READY column are 2/2, you can hit CTRL+C.

Make sure that the following command is running on Terminal 2 while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .2; done

The results should follow a fairly normal round-robin distribution pattern where v2 receives the request 3 times more than v1

customer => preference => recommendation v1 from '99634814-d2z2t': 1145
customer => preference => recommendation v2 from '2819441432-525lh': 1
customer => preference => recommendation v2 from '2819441432-rg45q': 2
customer => preference => recommendation v2 from '2819441432-bs5ck': 181
customer => preference => recommendation v1 from '99634814-d2z2t': 1146
customer => preference => recommendation v2 from '2819441432-rg45q': 3
customer => preference => recommendation v2 from '2819441432-rg45q': 4
customer => preference => recommendation v2 from '2819441432-bs5ck': 182

Now, explore the file istiofiles/destination-rule-recommendation_lb_policy_app.yml, and add the Random LB trafficPolicy defined in this DestinationRule:

istioctl create -f ~/projects/istio-tutorial/istiofiles/destination-rule-recommendation_lb_policy_app.yml -n tutorial

Make sure that the following command is running on Terminal 2 while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .2; done

After a while you should see a different pattern.

Clean up

Don't forget to remove the virtualservice and destinationrule executing ~/projects/istio-tutorial/scripts/clean.sh

and

oc scale deployment recommendation-v2 --replicas=1 -n tutorial

Important: The Rate Limiting rules take some time to be applied and reflected. Be patient here!

We can limit the request count rate in a specific microservice.

Examine the file that contains the rate limit handler istiofiles/recommendation_rate_limit_handler.yml and apply it

istioctl create -f ~/projects/istio-tutorial/istiofiles/recommendation_rate_limit_handler.yml

Now examine the file that contains the requestcount quota istiofiles/rate_limit_rule.yml and apply it

istioctl create -f ~/projects/istio-tutorial/istiofiles/rate_limit_rule.yml

To check the new behavior, try the microservice several times by typing while true; do curl http://customer-tutorial.[[HOST_SUBDOMAIN]]-80-[[KATACODA_HOST]].environments.katacoda.com; sleep .1; done

After some seconds, you should see some 429 errors:

customer => preference => recommendation v2 from '2819441432-f4ls5': 108
customer => preference => recommendation v1 from '99634814-d2z2t': 1932
customer => preference => recommendation v2 from '2819441432-f4ls5': 109
customer => preference => recommendation v1 from '99634814-d2z2t': 1933
customer => 503 preference => 429 Too Many Requests
customer => preference => recommendation v1 from '99634814-d2z2t': 1934
customer => preference => recommendation v2 from '2819441432-f4ls5': 110
customer => preference => recommendation v1 from '99634814-d2z2t': 1935
customer => 503 preference => 429 Too Many Requests
customer => preference => recommendation v1 from '99634814-d2z2t': 1936
customer => preference => recommendation v2 from '2819441432-f4ls5': 111
customer => preference => recommendation v1 from '99634814-d2z2t': 1937
customer => 503 preference => 429 Too Many Requests
customer => preference => recommendation v1 from '99634814-d2z2t': 1938
customer => preference => recommendation v2 from '2819441432-f4ls5': 112

Hit CTRL+C when you are satisfied.

Clean up

Don't forget to remove the rate limiting by executing oc delete -f projects/istio-tutorial/istiofiles/rate_limit_rule.yml