Introduction

This is a sample to show how to deploy with the canary strategy by ingress in kubernetes. Ingress support two strategies, canary by weight and canary by header.

Feature List

• test for canary by weight
• test for canary by header

How to test

Here will use env to flag the different app version. As the definition in app-1.0.0.yaml:

          env:
            - name: app.version
              value: 1.0.0

Please execute mvn clean install to build the image at first.

canary by weight

The yaml files are in the canary-weight directory. First write a script as follow for test:

#! /bin/bash
v1=0;
v2=0;
count=100;
while [ $count -gt 0 ];
do
  result=$(curl -s "http://shf.boot.com/app-service/get/app/version")
  flag=$(echo $result | grep "1.0.0")
  if [ "$flag" != "" ]
  then 
	  v1=$(expr $v1 + 1)
  else 
	  v2=$(expr $v2 + 1)
  fi	  
  count=$(expr $count - 1)
done;
echo $v1;
echo $v2;

• Deploy the app-1.0.0, now 100% traffic to version 1.0.0:

$ kubectl apply -f ./kubernetes/0namespace.yaml -f ./kubernetes/app-1.0.0.yaml -f ./kubernetes/ingress-1.0.0.yaml

• Execute the script, the result as follow：

100
0

We will always get 1.0.0.

• Deploy the version 2.0.0 by app-2.0.0

$ kubectl apply -f ./kubernetes/app-2.0.0.yaml 

• Next deploy the ingress-canary-2.0.0 to proxy the app-2.0.0, set 20% traffic to version 2.0.0:

$ kubectl apply -f ./kubernetes/canary-weight/ingress-canary-2.0.0.yaml

• Execute the script, the result as follow：

81
19

The output results are basically consistent with the expected preset ratio(20%).

• Until everything goes well, delete ingress-canary and deploy ingress-2.0.0 to set 100% traffic to version 2.0.0

$ kubectl delete -f ./kubernetes/canary-weight/ingress-canary-2.0.0.yaml
$ kubectl apply -f ./kubernetes/canary-weight/ingress-2.0.0.yaml

• Execute the script, the result as follow：

0
100

We will always get 2.0.0.

• Cleanup

$ kubectl delete ns canary-deploy

canary by header

The yaml files are in the canary-header directory. Write the test script as follow:

#! /bin/bash
echo $(curl -s -H "TAG: a" "http://shf.boot.com/app-service/get/app/version")
echo $(curl -s -H "TAG: b" "http://shf.boot.com/app-service/get/app/version")
echo $(curl -s -H "TAG: c" "http://shf.boot.com/app-service/get/app/version")
echo $(curl -s "http://shf.boot.com/app-service/get/app/version")
echo $(curl -s -H "TAG: d" "http://shf.boot.com/app-service/get/app/version")
echo $(curl -s -H "TAG: b" "http://shf.boot.com/app-service/get/app/version")

• Deploy the app-1.0.0, now 100% traffic to version 1.0.0:

$ kubectl apply -f ./kubernetes/0namespace.yaml -f ./kubernetes/app-1.0.0.yaml -f ./kubernetes/ingress-1.0.0.yaml

• Execute the script, the result as follow：

Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 1.0.0

We will always get 1.0.0.

• Deploy the version 2.0.0 by app-2.0.0

$ kubectl apply -f ./kubernetes/app-2.0.0.yaml 

• Next deploy the ingress-header-b to proxy the app-2.0.0. Then when the request include a header which is [TAG: b] will be oriented to version 2.0.0:

$ kubectl apply -f ./kubernetes/canary-header/ingress-header-b.yaml

• Re-run the script, the result as follow：

Current version is : 1.0.0
Current version is : 2.0.0
Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 1.0.0
Current version is : 2.0.0

As expected, the output of the second and sixth contain 2.0.0. Others contain 1.0.0.

• Until everything goes well, delete ingress-header-b and deploy ingress-2.0.0 to set 100% traffic to version 2.0.0

$ kubectl apply -f ./kubernetes/canary-header/ingress-2.0.0.yaml
$ kubectl delete -f ./kubernetes/canary-header/ingress-header-b.yaml

• Re-run the script, the result as follow：

Current version is : 2.0.0
Current version is : 2.0.0
Current version is : 2.0.0
Current version is : 2.0.0
Current version is : 2.0.0
Current version is : 2.0.0

We will always get 2.0.0.

• Cleanup

$ kubectl delete ns canary-deploy

Reference

• https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/annotations.md#canary