蓝绿色转换策略

Question

我正在测试在AWS上运行的k8s（1.7.4）上的蓝绿色更新，其中可以从k8s外部访问蓝绿色服务。当前的设置是蓝色的吊舱，绿色的吊舱和服务路由器。路由器设置是AWS ELB。该服务可通过指向ELB的CNAME访问。

问题在切换过程中。更新服务会产生新的ELB，从而为CNAME创建新的目标。等待DNS传播的时间是宕机时间。什么是避免停机的另一种方法？服务yml如下：

########## 
# ROUTER # 
########## 

# This blue green approach does not work because the AWS ELB must be created 
# new on each changeoever. This results in a new DNS record and clients are 
# lost while the new record propagates. 

# Expose the container as a service to the outside via DNS record and port. 
apiVersion: v1 
kind: Service 
metadata: 
    name: helloworld 
    annotations: 
    # URL for the service 
    external-dns.alpha.kubernetes.io/hostname: helloworld.k8s.example.net 
spec: 
    type: LoadBalancer 
    ports: 
    # Outside port mapped to deployed container port 
    - port: 80 
    targetPort: helloworldport 
    selector: 
    # HOWTO change app name to point to blue or green then 
    # ubectl replace -f bluegreenrouter.yml --force 
    app: helloworld-blue 

Answer 1

在更新K8S LoadBalancer类型服务期间，底层的ELB不应该改变。您确定您确实更新了服务（kubectl apply）而不是重新创建（kubectl delete/kubectl create）？