https://github.com/puneethkumarck/canary-microservice-deployment
https://github.com/puneethkumarck/canary-microservice-deployment
Last synced: 11 months ago
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- Host: GitHub
- URL: https://github.com/puneethkumarck/canary-microservice-deployment
- Owner: Puneethkumarck
- Created: 2022-02-19T23:34:25.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2022-02-20T13:43:04.000Z (over 4 years ago)
- Last Synced: 2025-06-17T22:41:46.755Z (12 months ago)
- Language: Java
- Size: 540 KB
- Stars: 0
- Watchers: 1
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Canary Deployments
Canary deployments are a pattern for rolling out releases to a subset of users or servers. The idea is to first deploy the change to a small subset of servers, test it, and then roll the change out to the rest of the servers.
In our below example you will learn following
* using the kubernetes labels to define the canary deployments
* Running multiple version of the application parrallel ,leave it to kubernetes service to load balance between new and old deployments
* test functionality of the new deployment
* Gracefully bring-down the old version
Initial Status of the application
Intermediate Status of the application
Final status of the application
Below is an small spring boot application which respond with greeting message
with initial deployment -> Hello from web2.0
with Final deployment -> Hello from web3.0
### Pre requisite installation
* Java 11
* maven
* kubernetes docker for desktop/minikube
### Tech
* Java 11
* Springboot
* Lombok
* Maven
* kubernetes
* Docker
### Clone
### generate spring boot project command-line
```
curl https://start.spring.io/starter.tgz -d dependencies=web,lombok -d baseDir=canary-microservice-deployment -d bootVersion=2.6.3 -d javaVersion=11 | tar -xzvf -
```
### Copy docker file to root directory with name Dockerfile
```
FROM openjdk:11.0-jdk-slim
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]
```
### Build
```
mvn clean install
```
```
Build docker image
docker build -t greeting .
```
```
docker image ls // list docker images
```
### Deploy
Kubernetes initial Deployment object with 3 replicas , notice labels with app: greeting and type:canary.
create kubernetes deployment and service file under k8s directory
```
apiVersion: apps/v1
kind: Deployment
metadata:
name: web2.0
labels:
app: greeting
type: canary
spec:
replicas: 3
selector:
matchLabels:
app: greeting
template:
metadata:
labels:
app: greeting
type: canary
spec:
containers:
- name: greeting
image: greeting:latest
ports:
- containerPort: 8080
imagePullPolicy: IfNotPresent
```
Kubernetes service
```
apiVersion: v1
kind: Service
metadata:
name: greetingservice
spec:
selector:
app: greeting
ports:
- port: 8080
targetPort: 8080
type: LoadBalancer
```
```
kubectl create -f k8s/deployment.yaml
```
```
kubectl get deployment,svc,po
```
### Run
```
while true; do curl http://localhost:8080/; sleep 2; done
You will see the always spring-boot service will respond with Hello from web2.0
```
## Canary deployment
update kubernetes deployment which uses configmap and diff replicas with new deployment name
```
apiVersion: apps/v1
kind: Deployment
metadata:
name: web3.0
labels:
app: greeting
type: canary
spec:
replicas: 1
selector:
matchLabels:
app: greeting
template:
metadata:
labels:
app: greeting
type: canary
spec:
containers:
- name: greeting
image: greeting:latest
imagePullPolicy: IfNotPresent
env:
- name: greeting.message
valueFrom:
configMapKeyRef:
name: canary-config
key: greeting.message
ports:
- containerPort: 8080
```
Create the configmap required for the new deployment
```
kubectl create configmap canary-config --from-literal=greeting.message="Hello from web3.0"
```
check the deployment objects to verify config map deployment
```
kubectl get deployment,svc,po,cm
```
deploy updated kubernetes deployment with latest changes as mentioned above
```
kubectl create -f k8s/deployment-new.yaml
```
observe new deployment appeared with name web3.0 in the above image
Now 25% of the traffic will route to new service deployment, now verify the service response , which will have mixed response from old and new deployment
```
while true; do curl http://localhost:8080/; sleep 2; done
```
once you test and make sure the new changes in the deployment , now scale down the old deployment and make the new deployment 100%.
currently we have an 3 replicas of old deployment and 1 replicas of new deployment
```
kubectl get deploy --show-labels
```
scale down the old deployment to zero instance and scale up the new deployment to 3 with below command
```
scale deploy web2.0 --replicas=0
kubectl scale deploy web3.0 --replicas=3
```
now test the application , which will respond always with new updated code.
```
while true; do curl http://localhost:8080/; sleep 2; done
```
