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This article introduces the relevant knowledge of "how to use Istio for A/B testing". In the actual case operation process, many people will encounter such difficulties. Next, let Xiaobian lead you to learn how to deal with these situations! I hope you can read carefully and learn something!

Question 1: I don't believe my test.

If the scope of the test doesn't completely cover the application you've changed, you may quickly take action to run a new round of testing, but it's also possible that the application won't work properly.

Ideally, we all want to make sure that every piece of code is thoroughly tested, otherwise we wouldn't be adding functionality to our application. But reality is always skinny, and we are often chased by ddl, which may have to be uploaded to the project before we can write or update the test.

Solution: Slow down

So how do I make sure that most of my users aren't affected by any bugs lurking in my code, and how do I make changes and deploy new features? The answer is to minimize the reach of these minor problems by deploying new versions to the fewest number of users first.

If the changes work as expected, you can slowly increase the percentage of users using the new version. If there are problems with metrics, you can easily roll back your changes and try again.

Can Canary deployment run on Kubernetes without Istio? Sure, but to automate this process, you need to focus entirely on web server code and custom automation scripts. This mode of operation is not cost-effective.

Istio has some very elegant traffic distribution solutions that we can use to provide the right client service for the right version at the right time, and we only need to adjust 1 or 2 parameters.

To do this, you need to set up an Ingress gateway, a virtual service, and a destination rule. This will sit on top of general deployments and services and distribute traffic for you.

apiVersion: networking.istio.io/v1alpha3kind: Gatewaymetadata: name: http-gatewayspec: selector: istio: ingressgateway servers: - port: number: 80 name: http protocol: HTTP hosts: - "*"---apiVersion: networking.istio.io/v1alpha3kind: VirtualServicemetadata: name: my-appspec: hosts: - "*" gateways: - http-gateway http: - match: - uri: prefix: "/my-app" rewrite: uri: "/" route: - destination: host: my-app subset: v1 port: number: 80 weight: 90 - destination: host: my-app subset: v2 port: number: 80 weight: 10---apiVersion: networking.istio.io/v1alpha3kind: DestinationRulemetadata: name: my-appspec: host: my-app subsets: - name: v1 labels: version: v1.0.0 - name: v2 labels: version: v2.0.0

As you can see from the Weight field for Virtual Services, Istio will distribute traffic between the two versions of the application based on the specified value. The sum of these values must be 100%, otherwise the API rejects the definition.

You (or ideally, manually performing one or more steps in the Continuous Integration/Continuous Delivery pipeline) will then adjust the weights to promote the new version to more users until all requests are satisfied by the new version and the previous version can be stopped from maintenance.

You can also integrate Istio into your integration test strategy by using Istio's fault injection capabilities to simulate network outages and actual traffic performance degradation.

If the idea of testing in production has left a psychological shadow on you, there must be something wrong with your approach. For example, try adding the following code snippet to your virtual service specification to add some clutter, and then find an article to see how Istio can solve that clutter.

spec: hosts: - my-app http: - fault: delay: fixedDelay: 7s percent: 100 route: - destination: host: ratings subset: v2 problem 2: marketing strategy unable to determine release

Often, businesses need to test multiple versions of an application against real-world users. But sometimes it's impossible to figure out which marketing strategy leads to the best conversion rate, or which design choice leads to the best customer Retention rate.

With Kubernetes, you can split traffic into two versions, but to get any valuable insights out of the exercise, again you need a whole lot of custom code to get the relevant information and process it in a way that non-technical colleagues can understand.

Solution: A/B testing with Istio

Istio's traffic distribution rules solve this problem again, and its tight integration with Prometheus and Grafana helps you get intuitive A/B test results. In general, depending on some part of the incoming packet content, there are almost infinite ways to decide which users can get the version of your application.

In this example, we will use the User-Agent field to provide different versions for different browsers.

apiVersion: networking.istio.io/v1alpha3kind: VirtualServicemetadata: name: my-appspec: hosts: - "*" gateways: - http-gateway http: - match: - headers: user-agent: regex: ".* Chrome.* " uri: prefix: "/my-app" rewrite: uri: "/" route: - destination: host: my-app subset: v1 port: number: 80 - match: - headers: user-agent: regex: ".* Mozilla.* " uri: prefix: "/my-app" rewrite: uri: "/" route: - destination: host: my-app subset: v2 port: number: 80

As you can see from the code above, Firefox users will get version 1 of the app, while Chrome users will get version 2. If the browser's User-Agent field doesn't contain either mozilla or chrome, neither will get either version.

To serve other customers, you need to add a default route, which I'll leave for you as an exercise. (hehe)

If you don't want to install another browser, but just want to try it out, you can use curl with a header logo to disguise yourself as any browser you want, for example:

curl /my-app -H "User-Agent: Chrome"

By changing the user-agent value, you can test all the different routes from the command line.

"How to use Istio for A/B testing" is introduced here, thank you for reading. If you want to know more about industry-related knowledge, you can pay attention to the website. Xiaobian will output more high-quality practical articles for everyone!

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