Kanary : Canary Release Operator for Kubernetes

This Kubernetes operator aims to manage canary release deployment using HAProxy container as L4 (TCP) loadbalancer

Operator installation

kubectl apply -f https://raw.githubusercontent.com/etiennecoutaud/kanary/master/manifests/kanary.yml

CustomRessourceDefinitions

Kanary Operator manipulate kanary custom ressource, short name is ky

kubectl get kanary
NAME                 AGE
simple-kanary-rule   9s

apiVersion: kanary.pyxida.io/v1alpha1
kind: Kanary
metadata:
  name: simple-kanary-rule
spec:
  destination: myapp
  routes:
  - backend:
     serviceName: "myapp-v1"
     servicePort: "http"
    weight: 80
  - backend:
      serviceName: "myapp-v2"
      servicePort: 9090
    weight: 20

In this example:

• HAProxy will be exposed by myapp service, indicated in destination field
• Canary release is loadbalancing to myapp-v1 and myapp-v2 services previously created by the user
• HAProxy referenced to service backend port with servicePort fiels, it can be port name or port value
• Loadbalancing is performed based on weight field
• Multiple backends can be set, sum of weight must be equal to 100

How it works

Kanary Operator will act on kanary CRD and will perform:

• HAProxy loabalancer generation
• Manage configuration and update based on weight loadbalancing
• Reference pod endpoint directly for more efficiency
• Trigger automatic HAProxy rolling update when configuration changed for no service outage
• Manage route as Kubernetes service to access to HAProxy

Kanary Operator is manipulating Kubernetes ressources:

• Deployment
• Endpoint
• ConfigMap
• Service

A RBAC dedicated role is needed to provide the ability to perform all operation on theses ressources

Architecture and example

Diagrams done with Kubernetes icons

Initial state: 2 version of the same application are running, each pods is exposed with a service

Kanary ressource is apply to the namespace to loadbalance pods depend on weight

This stack can be deployed in your cluster:

kubectl apply -f https://raw.githubusercontent.com/etiennecoutaud/kanary/master/examples/simple-stack.yml

License

The work done has been licensed under Apache License 2.0. The license file can be found here. You can find out more about the license at www.apache.org/licenses/LICENSE-2.0.