hayderimran7 / gitlab-auto-deploy-canary-chart

AutoDeploy Canary deployment chart

This chart is the modified form of official auto-deploy-app that is intended to achieve traffic routing in canary deployment using nginx-ingress.

Traffic Routing in Auto Deploy canary deployments using Nginx-ingress

The traffic routing in canary deployment is done based on header value while using nginx-ingress and AutoDevOps.

How it works

We used canary by header value feature of nginx-ingress annotations https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/#canary.
For that we had to modify official chart https://gitlab.com/gitlab-org/charts/auto-deploy-app to add two additional resources that are created during canary stage:

• canary-ingress : ingress-canary.yaml
• canary-service : service-canary.yaml

graph TD;
Z[Service URL ] --> A(Nginx Ingress);
A[Nginx Ingress ] --> B(Ingress);
A[Nginx Ingress ] -->|Header = canary:always| C(Canary Ingress);
B --> D[Service];
C --> E[Ingress Service];
D --> F[Production Deployment];
E --> G[Canary Deployment];

The canary-ingress checks for header canary, if set, routes to canary service backend that then forwards to canary-deployment.

NOTE : There was a bug in auto-deploy-app where the production service was pointing to both production deployment and production-canary deployment based on its selectors. This chart also takes care of it here

Testing in AutoDevops

Simply set CANARY_ENABLED in your .gitlab-ci.yml when using AutoDevops.
Deploy the app using this chart in production and then to canary. (this order is important because autodevops does not create any service/ingress in canary stage)

Now make a request to service URL as:

curl -H "canary: always" http://<service-url> 

This will hit the canary-ingress that will route to canary-deployment that you can verfiy in pod logs.