A git centric approach to A/B testing with Istio traffic shifting, Helm and Weave Flux.

1. A/B Testing with Istio and Helm
The GitOps Way
Stefan Prodan - stefan@weave.works
London August 2018
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2. ● Building cloud-native OSS since 2014
(Weave Net, Moby, Kubernetes, Prometheus)
● Founding member of CNCF
● Alexis Richardson (Weaveworks CEO) is chair of
the CNCF Technical Oversight Committee
● Weave Cloud runs on Kubernetes since 2015
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About Weaveworks

3. Introducing GitOps
GitOps builds on DevOps with Git as a single source of truth for the
desired state of the system
● The entire system state is under version control and described in a single Git
repository
● Operational changes on production clusters are made by pull request
● Rollback and audit logs are provided via Git
● When disaster strikes, the whole infrastructure can be quickly restored from Git

4. CI Image RegistryCode Repo
Typical CICD pipeline
ClusterDev RW
RW RWRW
RO RW RO

5. CICode Repo
Kubernetes API
GitOps CICD pipeline
Dev RO
RO
CD OperatorRO
RW
RW
RW
RW Image
Registry
Config Repo

6. Weave Flux - The GitOps Kubernetes Operator
Weave Flux implements a control loop that continuously applies the
desired state to your cluster, offering protection against harmful
actions like deployments deletion or network policies altering.
Weave Flux Helm Operator provides an extension to Weave Flux
that automates Helm Chart releases for it. A Chart release is
described through a Kubernetes custom resource named
FluxHelmRelease.

7. Weave Flux OSS
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Setup
helm repo add weaveworks https://weaveworks.github.io/flux
helm install --name flux weaveworks/flux
--namespace flux
--set helmOperator.create=true
--set helmOperator.git.chartsPath=charts
--set git.url=ssh://git@github.com/stefanprodan/gitops-istio
--set git.branch=ab-testing

8. GitOps for Helm

9. Flux Helm Release custom resource
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apiVersion: helm.integrations.flux.weave.works/v1alpha2
kind: FluxHelmRelease
metadata:
name: frontend
namespace: demo
annotations:
flux.weave.works/automated: "true"
flux.weave.works/tag.chart-image: semver:~1.0
spec:
chartGitPath: podinfo
releaseName: frontend
values:
image: quay.io/stefanprodan/podinfo:1.0.0

10. Secrets management

11. GitOps Demo
A/B Testing with Istio
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12. A/B Testing Initial State
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13. A/B Testing Desired State
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14. GitOps Examples
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● Helm
○ https://github.com/stefanprodan/gitops-helm
● Istio
○ https://github.com/stefanprodan/gitops-istio